PhD (Wollongong), MSc (Fudan), BE (Shanghai)
Dr Hao Liu joined UTS in 2012. Dr. Liu interests in the research fields of electrochemistry, nanotechnology and energy storage and conversion. He has developed the synthesis and applications for one-dimensional, mesoporous and novel core-shell structure materials. At UTS, he currently works part-time for high energy electrode materials (0.4 FTE, DP). He leads a team working on flexible hybrid devices. His results have been published in peer-reviewed journals, such as Journal of American Chemical Society, Advanced Materials, Angewandte Chemie International Edition, Nature Communications, Progress in Materials Science, Advanced Energy Materials, Advanced Functional Materials, Small, Journal of Chemistry Materials (A) etc. So far, he has published more than 80papers in peer-viewed journals (total IF > 800). His innovative work has been cited more than 9000 times, with an h-index of 40 (ISI Web of Science). Thirteen of his papers have been selected as "ESI Highly Cited papers". He has attracted more than $4.7 million funding as a CI. He is one of "2018 Highly Cited Researchers" selected by Clarivate Analytics.
Referee for peer-reviewed journals, including Adv. Mater., Angew. Chem. Int. Ed., Adv. Energy Mater., Adv. Funct. Mater., ACS Nano, Nano Energy, Small, Chem. Mater., Nanoscale, J. Mater. Chem. (A), Nano Research etc.
Associate Editor: Frontiers in Nanotechnology
Membrship: International Society of Electrochemistry, Chinese Chemical Society
Can supervise: YES
Dr. Hao Liu is an expert in the field of electrochemistry and energy storage. He interests in the synthesis of nanostructured materials and their applications in the fields of rechargeable lithium batteries, supercapacitors, gas sensors and fuel cells.
Inorganic Chemistry II (65509): 2013, 2014
Chemistry I (65111): 2012
2012.02 - 2012.06: Chemistry I; Inorganic Chemistry II.
2012.08 – 2012.11: Inorganic Chemistry I.
2013.03 – 2013.06: Inorganic Chemistry II.
2014.03 – 2014.06: Inorganic Chemistry II.
Gan, B, Tang, K, Chen, Y, Wang, D, Wang, N, Li, W, Wang, Y, Liu, H & Wang, G 2020, 'Concrete-like high sulfur content cathodes with enhanced electrochemical performance for lithium-sulfur batteries', JOURNAL OF ENERGY CHEMISTRY, vol. 42, pp. 174-179.View/Download from: Publisher's site
Guo, X, Zhang, W, Zhang, J, Zhou, D, Tang, X, Xu, X, Li, B, Liu, H & Wang, G 2020, 'Boosting Sodium Storage in Two-Dimensional Phosphorene/Ti3C2Tx MXene Nanoarchitectures with Stable Fluorinated Interphase', ACS NANO, vol. 14, no. 3, pp. 3651-3659.View/Download from: Publisher's site
Huo, J, Lu, L, Shen, Z, Liu, Y, Guo, J, Liu, Q, Wang, Y, Liu, H, Wu, M & Wang, G 2020, 'A rational synthesis of single-atom iron-nitrogen electrocatalysts for highly efficient oxygen reduction reaction', JOURNAL OF MATERIALS CHEMISTRY A, vol. 8, no. 32, pp. 16271-16282.View/Download from: Publisher's site
Nan, J, Guo, X, Xiao, J, Li, X, Chen, W, Wu, W, Liu, H, Wang, Y, Wu, M & Wang, G 2020, 'Nanoengineering of 2D MXene-Based Materials for Energy Storage Applications.', Small (Weinheim an der Bergstrasse, Germany).View/Download from: Publisher's site
2D MXene-based nanomaterials have attracted tremendous attention because of their unique physical/chemical properties and wide range of applications in energy storage, catalysis, electronics, optoelectronics, and photonics. However, MXenes and their derivatives have many inherent limitations in terms of energy storage applications. In order to further improve their performance for practical application, the nanoengineering of these 2D materials is extensively investigated. In this Review, the latest research and progress on 2D MXene-based nanostructures is introduced and discussed, focusing on their preparation methods, properties, and applications for energy storage such as lithium-ion batteries, sodium-ion batteries, lithium-sulfur batteries, and supercapacitors. Finally, the critical challenges and perspectives required to be addressed for the future development of these 2D MXene-based materials for energy storage applications are presented.
Potassium metal batteries are considered as attractive alternatives beyond lithium-ion batteries. However, uncontrollable dendrite growth on the potassium metal anode has restrained their practical applications. A high-performance potassium anode achieved by confining potassium metal into a titanium-deficient nitrogen-containing MXene/carbon nanotube freestanding scaffold is reported. The high electronic transport and fast potassium diffusion in this scaffold enable reduced local current density and homogeneous ionic flux during plating/stripping processes. Furthermore, as verified by theoretical calculations and experimental investigations, such "potassium-philic" MXene sheets can induce the nucleation of potassium, and guide potassium to uniformly distribute in the scaffold upon cycling. Consequently, the as-developed potassium metal anodes exhibit a dendrite-free morphology with high Coulombic efficiency and long cycle life during plating/stripping processes. Such anodes also deliver significantly improved electrochemical performances in potassium-sulfur batteries compared with bare potassium metal anodes. This work can provide a new avenue for developing potassium metal-based batteries.
Tian, H, Zhang, C, Su, P, Shen, Z, Liu, H, Wang, G, Liu, S & Liu, J 2020, 'Metal-organic-framework-derived formation of Co-N-doped carbon materials for efficient oxygen reduction reaction', JOURNAL OF ENERGY CHEMISTRY, vol. 40, pp. 137-143.View/Download from: Publisher's site
Xiong, P, Zhang, F, Zhang, X, Wang, S, Liu, H, Sun, B, Zhang, J, Sun, Y, Ma, R, Bando, Y, Zhou, C, Liu, Z, Sasaki, T & Wang, G 2020, 'Strain engineering of two-dimensional multilayered heterostructures for beyond-lithium-based rechargeable batteries', NATURE COMMUNICATIONS, vol. 11, no. 1.View/Download from: Publisher's site
Yu, X, Yu, Z-Y, Zhang, X-L, Li, P, Sun, B, Gao, X, Yan, K, Liu, H, Duan, Y, Gao, M-R, Wang, G & Yu, S-H 2020, 'Highly disordered cobalt oxide nanostructure induced by sulfur incorporation for efficient overall water splitting', NANO ENERGY, vol. 71.View/Download from: Publisher's site
Zhang, F, Guo, X, Xiong, P, Zhang, J, Song, J, Yan, K, Gao, X, Liu, H & Wang, G 2020, 'Interface Engineering of MXene Composite Separator for High-Performance Li-Se and Na-Se Batteries', ADVANCED ENERGY MATERIALS, vol. 10, no. 20.View/Download from: Publisher's site
Zhou, D, Tang, X, Guo, X, Li, P, Shanmukaraj, D, Liu, H, Gao, X, Wang, Y, Rojo, T, Armand, M & Wang, G 2020, 'Polyolefin-Based Janus Separator for Rechargeable Sodium Batteries', Angewandte Chemie.View/Download from: Publisher's site
© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Rechargeable sodium batteries are a promising technology for low-cost energy storage. However, the undesirable drawbacks originating from the use of glass fiber membrane separators have long been overlooked. A versatile grafting–filtering strategy was developed to controllably tune commercial polyolefin separators for sodium batteries. The as-developed Janus separators contain a single–ion-conducting polymer-grafted side and a functional low-dimensional material coated side. When employed in room-temperature sodium–sulfur batteries, the poly(1-[3-(methacryloyloxy)propylsulfonyl]-1-(trifluoromethanesulfonyl)imide sodium)-grafted side effectively enhances the electrolyte wettability, and inhibits polysulfide diffusion and sodium dendrite growth. Moreover, a titanium-deficient nitrogen-containing MXene-coated side electrocatalytically improved the polysulfide conversion kinetics. The as-developed batteries demonstrate high capacity and extended cycling life with lean electrolyte loading.
Zhou, D, Tang, X, Guo, X, Li, P, Shanmukaraj, D, Liu, H, Gao, X, Wang, Y, Rojo, T, Armand, M & Wang, G 2020, 'Polyolefin-Based Janus Separator for Rechargeable Sodium Batteries', ANGEWANDTE CHEMIE-INTERNATIONAL EDITION.View/Download from: Publisher's site
Huo, J, Ge, R, Liu, Y, Guo, J, Lu, L, Chen, W, Liu, C, Gao, H & Liu, H 2020, 'Recent advances of two-dimensional molybdenum disulfide based materials: Synthesis, modification and applications in energy conversion and storage', SUSTAINABLE MATERIALS AND TECHNOLOGIES, vol. 24.View/Download from: Publisher's site
Liu, Y, Huo, J, Guo, J, Lu, L, Shen, Z, Chen, W, Liu, C & Liu, H 2020, 'Hierarchical Porous Molybdenum Carbide Based Nanomaterials for Electrocatalytic Hydrogen Production', FRONTIERS IN CHEMISTRY, vol. 8.View/Download from: Publisher's site
Yang, X, Zu, H, Luo, L, Zhang, H, Li, J, Yi, X, Liu, H, Wang, F & Song, J 2020, 'Synergistic tungsten oxide/N, S co-doped carbon nanofibers interlayer as anchor of polysulfides for high-performance lithium-sulfur batteries', JOURNAL OF ALLOYS AND COMPOUNDS, vol. 833.View/Download from: Publisher's site
Guo, J, Huo, J, Liu, Y, Wu, W, Wang, Y, Wu, M, Liu, H & Wang, G 2019, 'Nitrogen-Doped Porous Carbon Supported Nonprecious Metal Single-Atom Electrocatalysts: from Synthesis to Application', Small Methods, vol. 3, no. 9.View/Download from: Publisher's site
© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Nonprecious metal single-atom materials have attracted extensive attention in the field of electrocatalysis due to their low cost, high reactivity, high selectivity, and high atomic utilization. However, the high surface energy of a single atom causes agglomeration during preparation and catalytic measurement, resulting in damage to the catalytic sites. The strong interaction between substrate and monoatoms is the key factor to prevent the aggregation of individual metal atoms, and the geometry and electronic structure of the catalysts can be adjusted to optimize the catalytic activity. Due to the hierarchically pores, high specific surface area, and defect effect, nitrogen-doped porous carbon (NPC) has been widely studied as an ideal nonprecious metal single-atom support, which synergistically enhance the electrocatalytic performance toward oxygen reduction reaction, oxygen evolution reaction, hydrogen evolution reaction, carbon dioxide reduction reaction, and nitrogen reduction reaction with non-noble metal single atoms. This review summarizes the controllable synthesis, characterization, theoretical calculation, and application of M (M = Co, Fe, Ni, Cu, Zn, Mo, etc.) single atoms on nitrogen-doped porous carbon. Finally, the future development and challenges of nitrogen-doped porous carbon supported nonprecious metal single-atom electrocatalysts for practical commercialization are concluded.
Guo, X, Zhang, J, Zhao, Y, Sun, B, Liu, H & Wang, G 2019, 'Ultrathin Porous NiCo2O4 Nanosheets for Lithium-Oxygen Batteries: An Excellent Performance Deriving from an Enhanced Solution Mechanism', ACS Applied Energy Materials, vol. 2, no. 6, pp. 4215-4223.View/Download from: Publisher's site
© Copyright 2019 American Chemical Society. Lithium-oxygen batteries are of interest for long-range electric vehicles owing to their high theoretical energy density. However, the poor cycling performance and low round-trip efficiency deriving from the sluggish oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) kinetics severely impede their practical application. Ingenious design of cathode catalysts is imperative to overcome these challenges. Here, we report ultrathin porous NiCo2O4 nanosheets with abundant oxygen vaccines as an efficient cathode catalyst toward both OER and ORR for Li-O2 batteries. From combined theoretical calculation with experimental results, a unique enhanced solution mechanism is proposed in the ether-based electrolyte system. Benefiting from the porous 2D architecture of the cathode and the hierarchical toroidal products, the Li-O2 batteries using NiCo2O4 cathodes deliver a high discharge capacity of 16 400 mAh g-1 at 200 mA g-1 and an excellent cycling performance up to 150 cycles with a restricted capacity of 1000 mAh g-1.
Tian, H, Liu, X, Dong, L, Ren, X, Liu, H, Price, CAH, Li, Y, Wang, G, Yang, Q & Liu, J 2019, 'Enhanced Hydrogenation Performance over Hollow Structured Co-CoOx@N-C Capsules.', Advanced Science, vol. 6, no. 22, pp. 1900807-1900807.View/Download from: Publisher's site
It is desirable to design nonprecious metal nanocatalysts with high stability and catalytic performance for fine chemicals production. Here, a method is reported for the preparation of cobalt metal and cobalt oxide cores confined within nanoporous nitrogen-doped hollow carbon capsules. Core-shell structured Zn/Co-ZIF@polymer materials are fabricated through a facile coating polymer strategy on the surface of zeolitic imidazolate frameworks (ZIF). A series of hollow carbon capsules with cobalt metal and cobalt oxide are derived from a facile confined pyrolysis of Zn/Co-ZIF@polymer. The hollow Co-CoOx@N-C capsules can prevent sintering and agglomeration of the cobalt nanoparticles and the nanoporous shell allows for efficient mass transport. The specific surface area and Co particle size are optimized through finely tuning the original Zn content in ZIF particles, thus enhancing overall catalytic activity. The yolk-shell structured Zn4Co1Ox@carbon hollow capsules are shown to be a highly active and selective catalyst (selectivity >99%) for hydrogenation of nitrobenzene to aniline. Furthermore, Zn4Co1Ox@carbon hollow particles show superior catalytic stability, and no deactivation after 8 cycles of reaction. The hollow Co-CoOx@N-C capsules may shed light on a green and sustainable catalytic process for fine chemicals production.
Wu, W, Zhao, Y, Li, S, He, B, Liu, H, Zeng, X, Zhang, J & Wang, G 2019, 'P doped MoS2 nanoplates embedded in nitrogen doped carbon nanofibers as an efficient catalyst for hydrogen evolution reaction.', Journal of colloid and interface science, vol. 547, pp. 291-298.View/Download from: Publisher's site
Two-dimensional (2D) molybdenum sulfide (MoS2) is considered as a promising catalyst for hydrogen evolution reaction (HER), originated from its abundant hydrogen evolution active sites. However, the HER performance of MoS2 is currently hindered by the limited exposed density of the active sites and low conductivity. Herein, we report a facile and scalable electrospinning technique to fabricate 2D MoS2 nanoplates doped with phosphorus within one-dimensional nitrogen doped-carbon nanofibers (NCNFs-MoS2|P) as a highly efficient HER catalyst. The space-confined growth with the presence of NCNFs avoided the stacking and aggregation of the MoS2 nanoplates, resulting in more exposed edge sites. The introduction of phosphorus atoms further activated the surface of MoS2 and enhanced the electron transfer. The overpotential of NCNFs-MoS2|P reached 98 mV at 10 mA cm-2, exhibiting excellent HER catalytic activity. Besides, almost no decay was observed after the stability test (5000 cycles or 20 h). The density functional calculations (DFT) elucidated that the incorporation of phosphorus atoms significantly improved the electrical conductivity and decreased the H adsorption energy barrier on MoS2, leading to a high catalytic performance of NCNFs-MoS2|P.
Xiao, J, Zhang, F, Tang, K, Li, X, Wang, D, Wang, Y, Liu, H, Wu, M & Wang, G 2019, 'Rational Design of a P2-Type Spherical Layered Oxide Cathode for High-Performance Sodium-Ion Batteries.', ACS Central Science, vol. 5, no. 12, pp. 1937-1945.View/Download from: Publisher's site
Sodium-ion batteries (SIBs) have been regarded as the most promising candidates for the next-generation energy storage devices owing to their low price and high abundance. However, the development of SIBs is mainly hindered by the instability of cathode materials. Here, we report a new P2-type manganese-rich cathode material, Na0.66Li0.18Mn0.71Mg0.21Co0.08O2 (P2-NaLiMMCO) with uniform spherical structure prepared via a simple solvothermal method and subsequent solid-state reaction. This P2-NaLiMMCO cathode material with uniform microsize secondary spheres and nanosize primary crystalline particles delivers a high initial discharge capacity of 166 mA h g-1 and superior capacity retention, which are superior to most previously reported results. The improved stability of the cathode material was further investigated by the in situ X-ray diffraction technique, which suggests an enhanced reversibility of the cathode material during the desodiation/sodiation process. With the superior electrochemical performance and stable structures, this new P2-NaLiMMCO can serve as a practical cathode material for SIBs.
Yang, T, Liu, J, Zhang, M, Yang, D, Zheng, J, Ju, Z, Cheng, J, Zhuang, J, Liu, Y, Zhong, J, Liu, H, Wang, G, Zheng, R & Guo, Z 2019, 'Encapsulating MnSe Nanoparticles Inside 3D Hierarchical Carbon Frameworks with Lithium Storage Boosted by in Situ Electrochemical Phase Transformation.', ACS applied materials & interfaces, vol. 11, pp. 33022-33032.View/Download from: Publisher's site
Electrode materials that act through the electrochemical conversion mechanism, such as metal selenides, have been considered as promising anode candidates for lithium-ion batteries (LIBs), although their fast capacity attenuation and inadequate electrical conductivity are impeding their practical application. In this work, these issues are addressed through the efficient fabrication of MnSe nanoparticles inside porous carbon hierarchical architectures for evaluation as anode materials for LIBs. Density functional theory simulations indicate that there is a completely irreversible phase transformation during the initial cycle, and the high structural reversibility of β-MnSe provides a low energy barrier for the diffusion of lithium ions. Electron localization function calculations demonstrate that the phase transformation leads to high charge transfer kinetics and a favorable lithium ion diffusion coefficient. Benefitting from the phase transformation and unique structural engineering, the MnSe/C chestnut-like structures with boosted conductivity deliver enhanced lithium storage performance (885 mA h g-1 at a current density of 0.2 A g-1 after 200 cycles), superior cycling stability (a capacity of 880 mA h g-1 at 1 A g-1 after 1000 cycles), and outstanding rate performance (416 mA h g-1 at 2 A g-1).
Yang, T, Liu, Y, Yang, D, Deng, B, Ling, CD, Liu, H, Wang, G, Guo, Z & Zheng, R 2019, 'Bimetallic metal-organic frameworks derived Ni-Co-Se@C hierarchical bundle-like nanostructures with high-rate pseudocapacitive lithium ion storage', Energy Storage Materials, vol. 17, pp. 374-384.View/Download from: Publisher's site
© 2018 Metal-organic frameworks and its derivates have attracted much attention for energy storage application. In this work, three-dimensional bimetallic metal-organic frameworks with novel hierarchical bundle-like micro/nanostructure were synthesized at room temperature for the first time. After initial carbonization and subsequent selenization, hierarchical porous Ni-Co-Se nanoparticles embedded in 3D carbon network with a high surface area that obviously inherited the original morphology of the bimetallic metal organic frameworks. The resulting materials demonstrated superior performance as the anode in lithium ion batteries (LIBs): they provide high reversible Li-storage capacity, excellent cyclability (2061 mA h/g after 300 cycles) and high rate performance (493 mA h/g at 8 A/g). The features of Ni-Co-Se@C electrode include the synergistic effect of two metal selenides species for Li-storage, well-designed hierarchical porous bundle-like structure, steady carbon network and as-formed size-reduced particles after initial cycle process. These features not only enhanced the electronic properties and alleviated the volume variation of metal selenides during the repeated cycles, but also produced more active sites for lithium storage and a shorter lithium diffusion pathway to expedite the fast charge transfer and preserve a stable SEI layer, resulting in outstanding lithium storage performance. In addition, the pseudocapacitive behaviour contributes much to the high energy storage of lithium ions. These results uncover a facile methodology for the design of well-organized MOFs and transition metal dichalcogenides with 3D hierarchical structures.
Yang, T, Yang, D, Mao, Q, Liu, Y, Bao, L, Chen, Y, Xiong, Q, Ji, Z, Ling, CD, Liu, H, Wang, G & Zheng, R 2019, 'In-situ synthesis of Ni-Co-S nanoparticles embedded in novel carbon bowknots and flowers with pseudocapacitance-boosted lithium ion storage.', Nanotechnology, vol. 30, no. 15.View/Download from: Publisher's site
We design a facile approach to prepare a bimetallic transition-metal-sulphide-based 3D hierarchically-ordered porous electrode based on bimetallic metal-organic frameworks (Ni-Co-MOFs) by using confinement growth and in-situ sulphurisation techniques. In the novel resulting architectures, Ni-Co-S nanoparticles are confined in bowknot-like and flower-like carbon networks and are mechanically isolated but electronically well-connected, where the carbon networks with a honeycomb-like feature facilitate electron transfer with uninterrupted conductive channels from all sides. Moreover, these hierarchically-ordered porous structures together with internal voids can accommodate the volume expansion of the embedded Ni-Co-S nanoparticles. The pseudocapacitive behaviours displayed in the NCS@CBs and NCS@CFs occupied a significant portion in the redox processes. Because of these merits, both the as-built bowknot and flower networks show excellent electrochemical properties for lithium storage with superior rate capability and robust cycling stability (994 mAh g-1 for NCS@CBs and 888 mAh g-1 for NCS@CFs after 200 cycles). This unique 3D hierarchically-ordered structural design is believed to hold great potential applications in propagable preparation of carbon networks teamed up with sulphide nanocrystals for high energy storage.
Zhang, F, Xiong, P, Guo, X, Zhang, J, Yang, W, Wu, W, Liu, H & Wang, G 2019, 'A nitrogen, sulphur dual-doped hierarchical porous carbon with interconnected conductive polyaniline coating for high-performance sodium-selenium batteries', Energy Storage Materials, vol. 19, pp. 251-260.View/Download from: Publisher's site
© 2019 Elsevier B.V. Sodium-selenium (Na-Se)battery has been emerging as a new rechargeable energy storage system with high capacity, low cost and high rate capability. However, the shuttling of polyselenides from the cathode to the anode causes dramatic capacity decay, severely impeding their practical applications. Herein, we report a combinational strategy of nitrogen and sulphur dual-doped hierarchical porous carbon with interconnected conductive polyaniline (PANI)coating to incorporate Se as stable cathodes (i-PANI@NSHPC/Se)for Na-Se batteries. Ex situ characterizations and density functional theory (DFT)calculations demonstrate that the i-PANI@NSHPC/Se cathode can provide both physical diffusion barrier and strong chemical affinity for polyselenides. In addition, the interconnected conductive polyaniline network enhances the conductivity for electrons and ions. With this strategy, the i-PANI@NSHPC/Se cathode delivered a high reversible capacity of 617 mAh g −1 after 200 cycles at 0.2C with a low capacity decay rate of 0.013% per cycle and an excellent rate capability at 20 C. Importantly, stable cycling performances were achieved with high capacities at different Se areal mass loadings (1.2, 2.3, 3.5 mg cm −2 ). This work could provide an efficient approach for developing Na-Se batteries with high active material mass loading, high rate capacity and long cycle life.
Zhao, Y, Wang, S, Liu, H, Guo, X, Zeng, X, Wu, W, Zhang, J & Wang, G 2019, 'Porous Mo2C nanorods as an efficient catalyst for the hydrogen evolution reaction', Journal of Physics and Chemistry of Solids, vol. 132, pp. 230-235.View/Download from: Publisher's site
© 2019 Elsevier Ltd Generate hydrogen fuel from electrochemical water splitting has been considered as a promising approach. However, to obtain the low-cost and high performance catalysts towards hydrogen evolution reaction (HER)which can be applied in both alkaline and acid solution remains a challenge. Herein, we synthesized an active and stable HER catalyst composed of Mo2C nanocrystals embedded in the nanocarbon layers (Mo2C@C)by using MoO3 nanorods as precursor. Benefiting from the porous one dimensional structure and ultrafine Mo2C nanocrystals, Mo2C@C exhibits high HER catalytic activity for 10 mA cm−2 with the overpotential of 119 mV in 1 M KOH solution and 170 mV in 0.5 M H2SO4 solution, respectively. Moreover, Mo2C@C displays long durability during the HER process with almost no decay and maintains the porous one dimensional architecture after the HER stability test. This study offers the guideline for the further design and fabrication of the nanostructured HER electrocatalysts in wide pH range.
Huo, J, Chen, Y, Liu, Y, Guo, J, Lu, L, Li, W, Wang, Y & Liu, H 2019, 'Bifunctional iron nickel phosphide nanocatalysts supported on porous carbon for highly efficient overall water splitting', Sustainable Materials and Technologies, vol. 22.View/Download from: Publisher's site
© 2019 The development of low-cost and earth-abundant materials for efficient oxygen and hydrogen evolution is critical for water splitting as a feasible energy conversion system. Metallic phosphides as promising bifunctional catalysts for water splitting tend to aggregate during the preparation and application. Thus, constructing metal phosphide-based composites with well-exposed active sites and stable structure is essential. Here, bi-metallic iron nickel phosphide nanoparticles (NPs) loaded on three-dimensional (3D) porous carbon (denoted as FexNi2-xP (0 < x < 2)) is synthesized through a facile co-deposition method followed by in situ phosphidation. The interconnected porous carbon with large specific area, abundant microporous and oxygen-containing functional groups contribute to the generation of ultra-small Fe–Ni–P NPs by confining growth of Fe–Ni layered double hydroxide (Fe–Ni–LDH) precursor. The ultra-small FexNi2-xP NPs loaded on 3D interconnected porous carbon with large active surface area and high conductivity can offer abundant catalytic active sites, facilitate mass transport and optimize electronic configuration, thereby promoting the reaction kinetics and accelerating catalytic performance. By tailoring the Ni/Fe ratios, the optimal bimetallic phosphide exhibits a small overpotential of 210 mV at current density of 10 mA cm−2 for oxygen evolution reaction. When applying for water splitting as cathode and anode materials in an alkaline electrolyzer, the potential of 1.63 V is required to reach 10 mA cm−2. The catalyst obtained from this strategy is a promising bi-functional catalyst for water splitting.
Wang, J, Su, P, Zhang, J, Wang, F, Chen, Y, Liu, H & Liu, J 2019, 'The formation of yolk-shell structured NiO nanospheres with enhanced lithium storage capacity', Materials Chemistry Frontiers, vol. 3, no. 8, pp. 1619-1625.View/Download from: Publisher's site
© 2019 the Partner Organisations. NiO has been widely applied as an anode material for lithium-ion batteries (LIBs), but the weak conductivity of NiO and serious volume expansion usually lead to poor cycling performance. Herein, we report the synthesis of well-crystallized yolk-shell structured NiO nanospheres (NiO-30) through the direct pyrolysis of Ni coordination polymers (Ni-CPs). Compared to commercial NiO used for LIB anode materials with a capacity of 369 mA h g-1, the resultant yolk-shell structured NiO nanospheres (NiO-30) demonstrate twice the capacity of 733 mA h g-1 at the current density of 100 mA g-1. Furthermore, the cycling stability and rate capability of the NiO-30 samples are much better than those of the commercial NiO. The yolk-shell structures can improve the electronic conductivity, benefit the Li+ ion transport path and buffer the volume changes during the lithium-insertion-extraction processes, which results in high discharge capacity, and good cycling performance and rate capability.
Chen, F, Ji, S, Liu, Q, Wang, H, Liu, H, Brett, DJL, Wang, G & Wang, R 2018, 'Rational Design of Hierarchically Core-Shell Structured Ni3 S2 @NiMoO4 Nanowires for Electrochemical Energy Storage.', Small, vol. 14, no. 27, pp. e1800791-e1800791.View/Download from: Publisher's site
Rational design and controllable synthesis of nanostructured materials with unique microstructure and excellent electrochemical performance for energy storage are crucially desired. In this paper, a facile method is reported for general synthesis of hierarchically core-shell structured Ni3 S2 @NiMoO4 nanowires (NWs) as a binder-free electrode for asymmetric supercapacitors. Due to the intimate contact between Ni3 S2 and NiMoO4 , the hierarchical structured electrodes provide a promising unique structure for asymmetric supercapacitors. The as-prepared binder-free Ni3 S2 @NiMoO4 electrode can significantly improve the electrical conductivity between Ni3 S2 and NiMoO4 , and effectively avoid the aggregation of NiMoO4 nanosheets, which provide more active space for storing charge. The Ni3 S2 @NiMoO4 electrode presents a high areal capacity of 1327.3 µAh cm-2 and 67.8% retention of its initial capacity when current density increases from 2 to 40 mA cm-2 . In a two-electrode Ni3 S2 @NiMoO4 //active carbon cell, the active materials deliver a high energy density of 121.5 Wh kg-1 at a power density of 2.285 kW kg-1 with excellent cycling stability.
Guo, X, Li, K, Bao, W, Zhao, Y, Xu, J, Liu, H & Wang, G 2018, 'Highly Reversible Lithium Polysulfide Semiliquid Battery with Nitrogen-Rich Carbon Fiber Electrodes', Energy Technology, vol. 6, no. 2, pp. 251-256.View/Download from: Publisher's site
© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Freestanding nitrogen-doped carbon fiber (NCF) webs saturated with lithium polysulfide solution were prepared as semiliquid cathodes for lithium–sulfur batteries. The NCF webs not only facilitated the transportation of electrons and ions but also immobilized the polysulfide at the cathode side because of strong affinity between the polysulfide and the N-doped carbon. As a result, these semiliquid cells demonstrated superior electrochemical performance at various current loads. A high reversible capacity of 900 mAh g−1was achieved after 200 cycles at a current rate of 1 C.
Guo, X, Zhang, J, Song, J, Wu, W, Liu, H & Wang, G 2018, 'MXene encapsulated titanium oxide nanospheres for ultra-stable and fast sodium storage', Energy Storage Materials, vol. 14, pp. 306-313.View/Download from: Publisher's site
© 2018 Sodium-ion batteries with high power density present tremendous potential for large-scale energy storage applications. However, it remains a big challenge to develop suitable anode materials for ultrafast and highly reversible sodium ion storage. Herein, for the first time, we report a novel strategy to fabricate highly conductive MXene Ti3C2Txencapsulated titanium oxide spheres (TiO2@Ti3C2Tx) as an excellent anode material for sodium-ion batteries. The MXene layers significantly improve the electronic conductivity of the whole electrode and protect the structural integrity of the TiO2spheres from electrochemical pulverization, which hence contributes to the formation of a stable solid-electrolyte interface. Meanwhile, the pseudocapacitance of the as-fabricated TiO2@Ti3C2Txcomposites enables high-rate capability and long cycle life in sodium-ion batteries. As a result, the hybrid electrode delivers a high reversible capacity of 116 mAh g-1at 960 mA g-1up to 5000 cycles. By coupling with a NaCrO2cathode, a prototype Na-ion full cell achieved a capacity of 103.4 mAh g-1at 960 mA g-1and an excellent cycling performance with 73.5% capacity retention after 1000 cycles.
Song, J, Zhang, C, Guo, X, Zhang, J, Luo, L, Liu, H, Wang, F & Wang, G 2018, 'Entrapping polysulfides by using ultrathin hollow carbon sphere-functionalized separators in high-rate lithium-sulfur batteries', Journal of Materials Chemistry A, vol. 6, no. 34, pp. 16610-16616.View/Download from: Publisher's site
© 2018 The Royal Society of Chemistry. Lithium-sulfur batteries (LSBs) have been regarded as the most promising technology for next generation energy storage systems owing to their high energy density and low cost. However, the undesirable shuttle effect and low utilization of sulfur caused by dissolution and migration of polysulfide intermediates greatly restrict their practical application. Herein, we report a functional separator modified with novel ultrathin hollow carbon spheres (UHCSs) to improve the overall performance of LSBs and demonstrate for the first time that nonporous hollow structured carbon materials are ideal candidates for modifying the separator due to their unique properties. The ultrathin and nonporous shell of the coated UHCSs can act as a physical and a chemical barrier to effectively entrap lithium polysulfides owing to fewer diffusion sites. The UHCSs can also enhance the electron transfer for sulfur and accommodate the large volume change of sulfur as upper current collectors. When applying such UHCSs functionalized separators, the LSBs achieved a significantly improved electrochemical performance including a high capacity of 1346.3 mA h g-1 at 0.2C and high rate capability with a discharge capacity of 458 mA h g-1 even at 5C upon 1000 cycles.
Tang, X, Liu, H, Guo, X, Wang, S, Wu, W, Mondal, AK, Wang, C & Wang, G 2018, 'A novel lithium-ion hybrid capacitor based on an aerogel-like MXene wrapped Fe2O3nanosphere anode and a 3D nitrogen sulphur dual-doped porous carbon cathode', Materials Chemistry Frontiers, vol. 2, no. 10, pp. 1811-1821.View/Download from: Publisher's site
© 2018 the Partner Organisations. Lithium-ion capacitors (LICs) have emerged as promising energy storage devices with both high energy density and high power density. However, due to the mismatch of charge-storage capacity and electrode kinetics between battery-type anodes and capacitor-type cathodes, the application of lithium-ion capacitors has been limited. In this work, interconnected aerogel-like MXene wrapped Fe2O3nanospheres have been prepared and investigated as battery-type anode materials for lithium-ion capacitors. In this rationally designed hybrid electrode, the Ti3C2TxMXene matrix is capable of providing fast transport of electrons and suppressing the volume change of Fe2O3. Simultaneously, Fe2O3hollow nanospheres offer large specific capacity and prevent restacking of the MXene layers, synergizing to boost the electrochemical performances of such hybrid electrodes. Meanwhile, the three-dimensional (3-D) nitrogen and sulphur dual-doped porous carbon (NS-DPC) derived from biomass has also been fabricated as a capacitor-type cathode material for lithium-ion capacitors. Consequently, the lithium-ion capacitors can demonstrate a high energy density of 216 W h kg-1at a power density of 400 W kg-1and a high power density of 20 kW kg-1at an energy density of 96.5 W h kg-1. This work elucidates that both high energy density and power density can be achieved in hybrid lithium-ion capacitors.
Yang, T, Liu, Y, Huang, Z, Liu, J, Bian, P, Ling, CD, Liu, H, Wang, G & Zheng, R 2018, 'In situ growth of ZnO nanodots on carbon hierarchical hollow spheres as high-performance electrodes for lithium-ion batteries', Journal of Alloys and Compounds, vol. 735, pp. 1079-1087.View/Download from: Publisher's site
© 2017 Elsevier B.V. Metal-organic frameworks (MOFs) is an ideal class of precursors or templates to build up transition metal based composites with unique architectures and high electrochemical performance for energy storage applications. In this work, a hybrid hollow nanoarchitecture made of ultrasmall zinc oxide nanodots (less than 5 nm in diameter) and carbon with 3D ordered hollow structure have been synthesized through a simple surfactant-assisted hydrothermal method followed by thermal annealing treatment. This 3D ordered hollow structure not only offers good electronic transportation routes and ionic conductive channels, but also effectively relieves the stress and mitigates the volume variation during lithiation/delithiation process as reflected by the high cycle stability and excellent rate capability as anode materials for lithium ion batteries. Benefitting from the rational design of 3D hollow structure and the synergistic effect between the ultrasmall ZnO nanodots and carbon framework, the ZnO/C hollow structures exhibit decent electrochemical performance of lithium storage with excellent cycling stability (a reversible capacity of 919 mA h/g over 100 cycles at 100 mA/g) and enhanced rate capability (567 mA h/g at high current density of 2 A/g). In addition, it also can deliver a capacity of 741 mA h/g at 500 mA/g after 120 cycles. These results uncover a facile route for the material design for energy application.
Zhao, Y, Zhang, J, Wu, W, Guo, X, Xiong, P, Liu, H & Wang, G 2018, 'Cobalt-doped MnO2 ultrathin nanosheets with abundant oxygen vacancies supported on functionalized carbon nanofibers for efficient oxygen evolution', Nano Energy, vol. 54, pp. 129-137.View/Download from: Publisher's site
© 2018 Elsevier Ltd Developing low-cost and efficient catalysts for oxygen evolution reactions (OER) with both excellent activity and robust stability remains a great challenge. Herein, we report a facile spontaneous redox reaction to grow cobalt-doped MnO2 ultrathin nanosheets in situ with abundant oxygen vacancies vertically aligned on cobalt/nitrogen co-functionalized carbon nanofibers (Co-MnO2|OV) as an efficient OER catalyst. It is confirmed that metallic cobalt plays a critical role in the formation of long and ultrathin MnO2 nanosheets during the redox reaction. Furthermore, the cobalt ions doped into MnO2 significantly enhance the catalytic activity of MnO2 nanosheets. Benefiting from the collaborative advantages of doping strategy, fast charge transfer kinetics and strong synergistic coupling effects, Co-MnO2|OV composites exhibit an excellent catalytic activity and a good durability for electrochemical water oxidation, reaching 10 mA cm−2 at an overpotential of 279 mV. According to the density functional theory (DFT) calculations, the enhanced catalytic activity mainly originates from a better conductivity and the decreased adsorption energy barrier of OH- on the O sites neighboring the doped Co and oxygen vacancies. Our findings suggest that the control over the structure and composition of the materials can achieve highly efficient oxygen evolution electrocatalysts.
Lei, Z, Yang, Q, Xu, Y, Guo, S, Sun, W, Liu, H, Lv, L-P, Zhang, Y & Wang, Y 2018, 'Boosting lithium storage in covalent organic framework via activation of 14-electron redox chemistry', NATURE COMMUNICATIONS, vol. 9.View/Download from: Publisher's site
Tang, X, Liu, H, Su, D, Notten, PHL & Wang, G 2018, 'Hierarchical sodium-rich Prussian blue hollow nanospheres as high-performance cathode for sodium-ion batteries', Nano Research, vol. 11, no. 8, pp. 3979-3990.View/Download from: Publisher's site
© 2018, Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature. Recently, Prussian blue and its analogues (PBAs) have attracted tremendous attention as cathode materials for sodium-ion batteries because of their good cycling performance, low cost, and environmental friendliness. However, they still suffer from kinetic problems associated with the solid-state diffusion of sodium ions during charge and discharge processes, which leads to low specific capacity and poor rate performances. In this work, novel sodium iron hexacyanoferrate nanospheres with a hierarchical hollow architecture have been fabricated as cathode material for sodium-ion batteries by a facile template method. Due to the unique hollow sphere morphology, sodium iron hexacyanoferrate nanospheres can provide large numbers of active sites and high diffusion dynamics for sodium ions, thus delivering a high specific capacity (142 mAh/g), a superior rate capability, and an excellent cycling stability. Furthermore, the sodium insertion/extraction mechanism has been studied by in situ X-ray diffraction, which provides further insight into the crystal structure change of the sodium iron hexacyanoferrate nanosphere cathode material during charge and discharge processes.
Dai, R, Sun, W, Lv, L-P, Wu, M, Liu, H, Wang, G & Wang, Y 2017, 'Bimetal-Organic-Framework Derivation of Ball-Cactus-Like Ni-Sn-P@C-CNT as Long-Cycle Anode for Lithium Ion Battery.', Small, vol. 13, no. 27, pp. 1-11.View/Download from: Publisher's site
Metal phosphides are a new class of potential high-capacity anodes for lithium ion batteries, but their short cycle life is the critical problem to hinder its practical application. A unique ball-cactus-like microsphere of carbon coated NiP2 /Ni3 Sn4 with deep-rooted carbon nanotubes (Ni-Sn-P@C-CNT) is demonstrated in this work to solve this problem. Bimetal-organic-frameworks (BMOFs, Ni-Sn-BTC, BTC refers to 1,3,5-benzenetricarboxylic acid) are formed by a two-step uniform microwave-assisted irradiation approach and used as the precursor to grow Ni-Sn@C-CNT, Ni-Sn-P@C-CNT, yolk-shell Ni-Sn@C, and Ni-Sn-P@C. The uniform carbon overlayer is formed by the decomposition of organic ligands from MOFs and small CNTs are deeply rooted in Ni-Sn-P@C microsphere due to the in situ catalysis effect of Ni-Sn. Among these potential anode materials, the Ni-Sn-P@C-CNT is found to be a promising anode with best electrochemical properties. It exhibits a large reversible capacity of 704 mA h g(-1) after 200 cycles at 100 mA g(-1) and excellent high-rate cycling performance (a stable capacity of 504 mA h g(-1) retained after 800 cycles at 1 A g(-1) ). These good electrochemical properties are mainly ascribed to the unique 3D mesoporous structure design along with dual active components showing synergistic electrochemical activity within different voltage windows.
Guo, X, Xie, X, Choi, S, Zhao, Y, Liu, H, Wang, C, Chang, S & Wang, G 2017, 'Sb2O3/MXene(Ti3C2Tx) hybrid anode materials with enhanced performance for sodium-ion batteries', Journal of Materials Chemistry A, vol. 5, no. 24, pp. 12445-12452.View/Download from: Publisher's site
Kretschmer, K, Sun, B, Zhang, J, Xie, X, Liu, H & Wang, G 2017, '3D Interconnected Carbon Fiber Network-Enabled Ultralong Life Na3 V2 (PO4 )3 @Carbon Paper Cathode for Sodium-Ion Batteries.', Small, vol. 13, no. 9.View/Download from: Publisher's site
Sodium-ion batteries (NIBs) are an emerging technology, which can meet increasing demands for large-scale energy storage. One of the most promising cathode material candidates for sodium-ion batteries is Na3 V2 (PO4 )3 due to its high capacity, thermal stability, and sodium (Na) Superionic Conductor 3D (NASICON)-type framework. In this work, the authors have significantly improved electrochemical performance and cycling stability of Na3 V2 (PO4 )3 by introducing a 3D interconnected conductive network in the form of carbon fiber derived from ordinary paper towel. The free-standing Na3 V2 (PO4 )3 -carbon paper (Na3 V2 (PO4 )3 @CP) hybrid electrodes do not require a metallic current collector, polymeric binder, or conducting additives to function as a cathode material in an NIB system. The Na3 V2 (PO4 )3 @CP cathode demonstrates extraordinary long term cycling stability for 30 000 deep charge-discharge cycles at a current density of 2.5 mA cm(-2) . Such outstanding cycling stability can meet the stringent requirements for renewable energy storage.
Liu, H, Liu, X, Li, W, Guo, X, Wang, Y, Wang, G & Zhao, D 2017, 'Porous Carbon Composites for Next Generation Rechargeable Lithium Batteries', Advanced Energy Materials, vol. 7, no. 24, pp. 1-11.View/Download from: Publisher's site
Rechargeable Mg–air batteries are a promising alternative to Li–air cells owing to the safety, low price originating from the abundant resource on the earth, and high theoretical volumetric density (3832 A h L−1 for Mg anode vs 2062 A h L−1 for Li). Only a few works are related to the highly reversible Mg–air batteries. The fundamental scientific difficulties hindering the rapid development of secondary Mg–air cells are attributed to the poor thermodynamics and kinetics properties mainly owing to the MgO or MgO2 insulating film as the initial discharge product on air–breathing cathode, contributing to the increase of a large overpotential and a high polarization. Very recently, remarkable progress on rechargeable Mg–air batteries is trying to overcome the major limitations in organic electrolytes via the combination of the first–principle calculation and experimental study. Therefore, this progress report highlights a comprehensive and concise survey of the major progress in the history of secondary Mg–air batteries, and the detailed illustrations of corresponding reaction mechanisms. The overview is devoted to open up a new area for manipulating the nanostructures to control the ideal reaction pathway in novel cell configuration and to fully understand the future Mg–air battery with improved energy density and cycling ability.
Mondal, AK, Kretschmer, K, Zhao, Y, Liu, H, Fan, H & Wang, G 2017, 'Naturally nitrogen doped porous carbon derived from waste shrimp shells for high-performance lithium ion batteries and supercapacitors', Microporous and Mesoporous Materials, vol. 246, pp. 72-80.View/Download from: Publisher's site
© 2017 Elsevier Inc. Transformation of biomass wastes into sustainable low cost carbon materials is now a topic of great interest. Here, we describe porous carbon from biomass derived waste shrimp shells and its application in two different energy storage systems. The unique porous structure with the presence of he teroatoms (O, N) makes it promising material for both lithium ion batteries and supercapacitors. When applied as anode materials for lithium ion batteries, the as-prepared carbon showed a specific capacity as high as 1507 mA h g −1 and 1014 mA h g −1 at current densities of 0.1 A g −1 and 0.5 A g −1 , respectively, good rate performance and superior cycling stability. The porous carbon-based supercapacitor also delivered a specific capacitance of 239 F g −1 at a current density of 0.5 A g −1 in 6 M KOH electrolyte. The specific capacitance retention is 99.4% even after 5000 charge-discharge cycles, indicating excellent cycling stability. The superior electrochemical performances for both lithium ion batteries and supercapacitors could be ascribed to the high specific surface area, porous structure and nitrogen doping effect.
Mondal, AK, Kretschmer, K, Zhao, Y, Liu, H, Wang, C, Sun, B & Wang, G 2017, 'Nitrogen-Doped Porous Carbon Nanosheets from Eco-Friendly Eucalyptus Leaves as High Performance Electrode Materials for Supercapacitors and Lithium Ion Batteries.', Chemistry - A European Journal, vol. 23, no. 15, pp. 3683-3690.View/Download from: Publisher's site
Nitrogen-doped porous carbon nanosheets were prepared from eucalyptus tree leaves by simply mixing the leaf powders with KHCO3 and subsequent carbonisation. Porous carbon nanosheets with a high specific surface area of 2133 m(2) g(-1) were obtained and applied as electrode materials for supercapacitors and lithium ion batteries. For supercapacitor applications, the porous carbon nanosheet electrode exhibited a supercapacitance of 372 F g(-1) at a current density of 500 mA g(-1) in 1 m H2 SO4 aqueous electrolyte and excellent cycling stability over 15 000 cycles. In organic electrolyte, the nanosheet electrode showed a specific capacitance of 71 F g(-1) at a current density of 2 Ag(-1) and stable cycling performance. When applied as the anode material for lithium ion batteries, the as-prepared porous carbon nanosheets also demonstrated a high specific capacity of 819 mA h g(-1) at a current density of 100 mA g(-1) , good rate capability, and stable cycling performance. The outstanding electrochemical performances for both supercapacitors and lithium ion batteries are derived from the large specific surface area, porous nanosheet structure and nitrogen doping effects. The strategy developed in this paper provides a novel route to utilise biomass-derived materials for low-cost energy storage systems.
Sun, W, Yu, Z, Lv, LP, Xu, Y, Liu, H, Wang, G & Wang, Y 2017, 'Mn3O4Nanosheet and GNS– Mn3O4Composite as High-Performance Anode Materials for Lithium-Ion Batteries', Arabian Journal for Science and Engineering, vol. 42, no. 10, pp. 4281-4289.View/Download from: Publisher's site
© 2017, King Fahd University of Petroleum & Minerals. Nanostructured transitional metal oxides have received more and more attention as the electrode materials for lithium-ion batteries to achieve high specific capacity and good safety performance. In this paper, a graphene nanosheet-supported Mn 3 O 4 nanoparticles (Mn 3 O 4 –GNS) composite, as well as Mn 3 O 4 nanosheet, were synthesized via a facile hydrothermal method. The Mn 3 O 4 –GNS composite exhibits good electrochemical performances with high reversible specific capacity (an initial charge capacity of 969 mAh g - 1 at 93.6 mA g - 1 ), good cycling stability (a retained capacity of 646 mAh g - 1 after 60 cycles) and rate capability when used as the anode material for LIBs. The enhanced electrochemical performance could be attributed to the nanoscaled particle s of Mn 3 O 4 , the buffer and confine effects of graphene nanosheets (GNSs) and the distinctive synergistic effect between two components of GNS and metal oxides.
Tian, H, Liu, H, Yang, T, Veder, J-P, Wang, G, Hu, M, Wang, S, Jaroniec, M & Liu, J 2017, 'Fabrication of core–shell, yolk–shell and hollow Fe 3 O 4 @carbon microboxes for high-performance lithium-ion batteries', Materials Chemistry Frontiers, vol. 1, no. 5, pp. 823-830.View/Download from: Publisher's site
Metal oxide–carbon composites with core–shell, yolk–shell and hollow structures have attracted enormous interest because of their applications in lithium-ion batteries. However, the relationship between structure and battery performance is still unclear. Herein, we report the designed synthesis of unique core–shell, yolk–shell and hollow Fe3O4@carbon microboxes through a one-step Stöber coating method, followed by a carbonization process. Different calcination temperatures were investigated to manipulate the various structures, and the impact of layer thickness on the battery performance was also assessed. Our results showed that the core–shell structured Fe3O4@carbon microboxes with nitrogen-doped carbon shells having a thickness of 15 nm exhibited an excellent performance in lithium-ion batteries with a high reversible capacity of 857 mA h g−1 that could be retained after 100 cycles at a current density of 0.1 A g−1.
Zhao, Y, Zhang, J, Guo, X, Fan, H, Wu, W, Liu, H & Wang, G 2017, 'Fe3C@nitrogen doped CNT arrays aligned on nitrogen functionalized carbon nanofibers as highly efficient catalysts for the oxygen evolution reaction', Journal of Materials Chemistry A, vol. 5, no. 37, pp. 19672-19679.View/Download from: Publisher's site
© 2017 The Royal Society of Chemistry. Fe 3 C based catalysts are found to be one of the most promising electrocatalysts for the oxygen evolution reaction (OER). Herein, we report on a nanoarchitectured material composed of Fe 3 C nanoparticles encapsulated at the tip of nitrogen-enriched carbon nanotubes (NCNTs), which are aligned on one dimensional (1D) nitrogen-doped carbon nanofibers (Fe 3 C@NCNTs-NCNFs) by a scalable electrospinning technique, as a high performance OER catalyst. The unique 3D hierarchical architecture of Fe 3 C@NCNTs-NCNFs leads to highly exposed active sites, enhanced electron transfer properties and strong synergistic coupled effects. Fe 3 C@NCNTs-NCNFs exhibit an outstanding catalytic performance with a high current density (10 mA cm -2 at an overpotential of 284 mV), a low Tafel slope (56 mV dec -1 ), a low charge transfer resistance and strong durability in 1 M KOH solution. The electrochemical evaluation demonstrates that the Fe 3 C@NCNTs-NCNF composite is a promising electrocatalyst for the OER in alkaline solution.
Guo, X, Sun, B, Su, D, Liu, X, Liu, H, Wang, Y & Wang, G 2017, 'Recent developments of aprotic lithium-oxygen batteries: functional materials determine the electrochemical performance', Science Bulletin, vol. 62, no. 6, pp. 442-452.View/Download from: Publisher's site
© 2017 Lithium oxygen battery has the highest theoretical capacity among the rechargeable batteries and it can reform energy storage technology if it comes to commercialization. However, many critical challenges, mainly embody as low charge/discharge round-trip efficiency and poor cycling stability, impede the development of Li-O 2 batteries. The electrolyte decomposition, lithium metal anode corrosion and sluggish oxygen reaction kinetics at cathode are all responsible for poor electrochemical performances. Particularly, the catalytic cathode of Li-O 2 batteries, playing a crucial role to reduce the oxygen during discharging and to decompose discharge products during charging, is regarded as a breakthrough point that has been comprehensive investigated. In this review, the progress and issues of electrolyte, anode and cathode, especially the catalysts used at cathode, are systematically summarized and discussed. Then the perspectives toward the developments of a long life Li-O 2 battery are also presented at last.
Guo, X, Sun, B, Zhang, J, Liu, H & Wang, G 2016, 'Ruthenium decorated hierarchically ordered macro-mesoporous carbon for lithium oxygen batteries', JOURNAL OF MATERIALS CHEMISTRY A, vol. 4, no. 25, pp. 9774-9780.View/Download from: Publisher's site
Mondal, AK, Liu, H, Li, Z-F & Wang, G 2016, 'Multiwall carbon nanotube-nickel cobalt oxide hybrid structure as high performance electrodes for supercapacitors and lithium ion batteries', ELECTROCHIMICA ACTA, vol. 190, pp. 346-353.View/Download from: Publisher's site
Mondal, AK, Liu, H, Xie, X, Kretschmer, K & Wang, G 2016, 'Hydrothermal Synthesis of Multiwalled Carbon Nanotube-Zinc Manganate Nanoparticles as Anode Materials for Lithium Ion Batteries', CHEMPLUSCHEM, vol. 81, no. 4, pp. 399-405.View/Download from: Publisher's site
Song, J, Sun, B, Liu, H, Ma, Z, Chen, Z, Shao, G & Wang, G 2016, 'Enhancement of the Rate Capability of LiFePO4 by a New Highly Graphitic Carbon-Coating Method', ACS Applied Materials and Interfaces, vol. 8, no. 24, pp. 15225-15231.View/Download from: Publisher's site
Low lithium ion diffusivity and poor electronic conductivity are two major drawbacks for the wide application of LiFePO4 in high-power lithium ion batteries. In this work, we report a facile and efficient carbon-coating method to prepare LiFePO4/graphitic carbon composites by in situ carbonization of perylene-3,4,9,10-tetracarboxylic dianhydride during calcination. Perylene-3,4,9,10-tetracarboxylic dianhydride containing naphthalene rings can be easily converted to highly graphitic carbon during thermal treatment. The ultrathin layer of highly graphitic carbon coating drastically increased the electronic conductivity of LiFePO4. The short pathway along the  direction of LiFePO4 nanoplates could decrease the Li+ ion diffusion path. In favor of the high electronic conductivity and short lithium ion diffusion distance, the LiFePO4/graphitic carbon composites exhibit an excellent cycling stability at high current rates at room temperature and superior performance at low temperature (−20 °C).
Zhao, Y, Zhang, J, Li, K, Ao, Z, Wang, C, Liu, H, Sun, K & Wang, G 2016, 'Electrospun cobalt embedded porous nitrogen doped carbon nanofibers as an efficient catalyst for water splitting', JOURNAL OF MATERIALS CHEMISTRY A, vol. 4, no. 33, pp. 12818-12824.View/Download from: Publisher's site
Ao, Z, Jiang, Q, Li, S, Liu, H, Peeters, FM, Li, S & Wang, G 2015, 'Enhancement of the Stability of Fluorine Atoms on Defective Graphene and at Graphene/Fluorographene Interface.', ACS applied materials & interfaces, vol. 7, pp. 19659-19665.View/Download from: Publisher's site
Fluorinated graphene is one of the most important derivatives of graphene and has been found to have great potential in optoelectronic and photonic nanodevices. However, the stability of F atoms on fluorinated graphene under different conditions, which is essential to maintain the desired properties of fluorinated graphene, is still unclear. In this work, we investigate the diffusion of F atoms on pristine graphene, graphene with defects, and at graphene/fluorographene interfaces by using density functional theory calculations. We find that an isolated F atom diffuses easily on graphene, but those F atoms can be localized by inducing vacancies or absorbates in graphene and by creating graphene/fluorographene interfaces, which would strengthen the binding energy of F atoms on graphene and increase the diffusion energy barrier of F atoms remarkably.
Liu, H, Li, W, Shen, D, Zhao, D & Wang, G 2015, 'Graphitic Carbon Conformal Coating of Mesoporous TiO2 Hollow Spheres for High-Performance Lithium Ion Battery Anodes', JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, vol. 137, no. 40, pp. 13161-13166.View/Download from: Publisher's site
Liu, H, Zheng, Y, Wang, G & Qiao, SZ 2015, 'A Three-Component Nanocomposite with Synergistic Reactivity for Oxygen Reduction Reaction in Alkaline Solution', ADVANCED ENERGY MATERIALS, vol. 5, no. 3.View/Download from: Publisher's site
Sun, B, Chen, S, Liu, H & Wang, G 2015, 'Mesoporous Carbon Nanocube Architecture for High-Performance Lithium-Oxygen Batteries', ADVANCED FUNCTIONAL MATERIALS, vol. 25, no. 28, pp. 4436-4444.View/Download from: Publisher's site
Zhao, Y, Xie, X, Zhang, J, Liu, H, Ahn, HJ, Sun, K & Wang, G 2015, 'MoS2 Nanosheets Supported on 3D Graphene Aerogel as a Highly Efficient Catalyst for Hydrogen Evolution.', Chemistry (Weinheim an der Bergstrasse, Germany), vol. 21, no. 45, pp. 15908-15913.View/Download from: Publisher's site
The development of efficient catalysts for electrochemical hydrogen evolution is essential for energy conversion technologies. Molybdenum disulfide (MoS2 ) has emerged as a promising electrocatalyst for hydrogen evolution reaction, and its performance greatly depends on its exposed edge sites and conductivity. Layered MoS2 nanosheets supported on a 3D graphene aerogel network (GA-MoS2 ) exhibit significant catalytic activity in hydrogen evolution. The GA-MoS2 composite displays a unique 3D architecture with large active surface areas, leading to high catalytic performance with low overpotential, high current density, and good stability.
Zhang, Y, Bhadbhade, M, Karatchevtseva, I, Price, JR, Liu, H, Zhang, Z, Kong, L, Cejka, J, Lu, K & Lumpkin, GR 2015, 'Uranium(VI) coordination polymers with pyromellitate ligand: Unique 1D channel structures and diverse fluorescence', JOURNAL OF SOLID STATE CHEMISTRY, vol. 226, pp. 42-49.View/Download from: Publisher's site
Li, K, Su, D, Liu, H & Wang, G 2015, 'Antimony-Carbon-Graphene Fibrous Composite as Freestanding Anode Materials for Sodium-ion Batteries', Electrochimica Acta, vol. 177, pp. 304-309.View/Download from: Publisher's site
© 2015 Elsevier Ltd. Antimony-carbon-graphene fibrous composites were prepared by the electrospinning/spray process as freestanding anodes for sodium-ion batteries. Antimony nanoparticles distribute in conductive carbonized polymer fibers and graphene flakes. The unique structure prevents the aggregation of the antimony nanoparticles and buffers the mechanical stress from volume change of antimony during repeated alloying/de-alloying process. The composites demonstrated an excellent electrochemical performance as anode material for sodium-ion batteries, with a reversible capacity of 274 mAh/g after 100 charge-discharge cycles at a current density of 100 mA/g.
Mondal, AK, Chen, S, Su, D, Kretschmer, K, Liu, H & Wang, G 2015, 'Microwave synthesis of alpha-Fe2O3 nanoparticles and their lithium storage properties: A comparative study', JOURNAL OF ALLOYS AND COMPOUNDS, vol. 648, pp. 732-739.View/Download from: Publisher's site
Zhao, Y, Chen, S, Sun, B, Su, D, Huang, X, Liu, H, Yan, Y, Sun, K & Wang, G 2015, 'Graphene-Co3O4 nanocomposite as electrocatalyst with high performance for oxygen evolution reaction', SCIENTIFIC REPORTS, vol. 5.View/Download from: Publisher's site
Zhao, Y, Sun, B, Huang, X, Liu, H, Su, D, Sun, K & Wang, G 2015, 'Porous graphene wrapped CoO nanoparticles for highly efficient oxygen evolution', JOURNAL OF MATERIALS CHEMISTRY A, vol. 3, no. 10, pp. 5402-5408.View/Download from: Publisher's site
Chen, S, Huang, X, Liu, H, Sun, B, Yeoh, W, Li, K, Zhang, J & Wang, G 2014, '3D Hyperbranched Hollow Carbon Nanorod Architectures for High-Performance Lithium-Sulfur Batteries', Advanced Energy Materials, vol. 4, p. 1301761.View/Download from: Publisher's site
Lithium-sulfur batteries have been plagued for a long time by low Coulombic efficiency, fast capacity loss, and poor high rate performance. Here, the synthesis of 3D hyperbranched hollow carbon nanorod encapsulated sulfur nanocomposites as cathode materials for lithium-sulfur batteries is reported. The sulfur nanocomposite cathodes deliver a high specific capacity of 1378 mAh g-1 at a 0.1C current rate and exhibit stable cycling performance. The as-prepared sulfur nanocomposites also achieve excellent high rate capacities and cyclability, such as 990 mAh g -1 at 1C, 861 mAh g -1 at 5C, and 663 mAh g -1 at 10C, extending to more than 500 cycles. The superior electrochemical performance are ascribed to the unique 3D hyperbranched hollow carbon nanorod architectures and high length/radius aspect ratio of the carbon nanorods, which can effectively prevent the dissolution of polysulfi des, decrease self-discharge, and confi ne the volume expansion on cycling. High capacity, excellent high-rate performance, and long cycle life render the as-developed sulfur/carbon nanorod nanocomposites a promising cathode material for lithium-sulfur batteries.
Chen, S, Huang, X, Sun, B, Zhang, J, Liu, H & Wang, G 2014, 'Multi-shelled hollow carbon nanospheres for lithium–sulfur batteries with superior performances', J. Mater. Chem. A, vol. 2, no. 38, pp. 16199-16207.View/Download from: Publisher's site
The anodic properties of antimony trioxide (Sb2O3) nanowires were investigated as electrode material for sodium-ion battery. Sb2O3 nanowires were prepared via a mild-condition, solvothermal route based on the hydrolysis of antimony trichloride (SbCl3) in alcohol aqueous solution. The uniform morphology and crystal phases of Sb2O3 nanowires are confirmed by scanning electronic microscopy, transmission electronic microscopy, and X-ray diffraction. The electrochemical performance of Sb2O3 nanowire anodes was studied and thematerial exhibits a high reversible capacity of 230 mAh/g which is attributed to the reversible complex conversion-alloying reactions between antimony trioxide and sodium.
Liu, H & Wang, G 2014, 'An investigation of the morphology effect in Fe2O3 anodes for lithium ion batteries', Journal of Materials Chemistry A, vol. 2, pp. 9955-9959.View/Download from: Publisher's site
Morphology control strategies have been widely used to boost the tolerance of anode materials against a dramatic volume change during charge/discharge processes. Herein, we found solid scientific evidence demonstrating that the electrochemical properties of cavity containing materials are superior to their solid counterparts.
Liu, J, Liu, H, Yang, T, Wang, G & Tade, MO 2014, 'Mesoporous carbon with large pores as anode for Na-ion batteries', Chinese Science Bulletin, vol. 59, no. 18, pp. 2186-2190.View/Download from: Publisher's site
Sodium ion (Na+) batteries have attracted increased attention for energy storage owing to the natural abundance and low cost of sodium. Herein, we report the synthesis of mesoporous carbon with large pores as anode for Na-ion batteries. The mesoporous carbon was obtained by carbonization and dense packing of 50 nm resorcinol and formaldehyde spheres synthesized through an extension Stöber method. Our work demonstrates that replacement of lithium by sodium using large pore carbon as anode might offer an alternative route for rechargeable batteries.
Mondal, AK, Chen, S, Su, D, Liu, H & Wang, G 2014, 'Fabrication and enhanced electrochemical performances of Mo03/graphene composite as anode material for lithium-ion batteries', International Journal of Smart Grid and Clean Energy, vol. 3, no. 2, pp. 142-148.
Molybdenum trioxide (Mo0#)/graphene composite were prepared by integrating Mo03 and graphene in dimethylformamide (DMF). The morphology and structure of the materials were characterized by X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy. The electrochemical properties of Mo03/graphene composite with different ratios were studied as anode materials for lithium-ion batteries using galavanostatic charge-discharge and cyclic voltammetry. We observed that the Mo03/graphene anode with a weight ratio of 1:1 (Mo03 graphene) exhibits a high lithium storage capacity of 967 mA h g-1 at the current density of 500 mA g-1, satisfactory cycling stability and good rate capability.
Liu, H, Chen, S, Wang, G & Qiao, SZ 2013, 'Ordered Mesoporous Core/Shell SnO2/C Nanocomposite as High capacity Anode Material for Lithium Ion Battery', Chemistry -A European Journal, vol. 19, no. 50, pp. 16897-16901.View/Download from: Publisher's site
An ordered mesoporous core/shell structured SnO2/C nanocomposite was obtained from a facile vacuum-assisted impregnation route by using SBA-15 as a hard template. The nanocomposoite exhibits high specific capacity and excellent high-rate performance as an anode material for lithium-ion battery (see graph).
Su, D, Liu, H, Ahn, H & Wang, G 2013, 'Synthesis of Highly Ordered Mesoporous Co3O4 for Gas Sensing', Journal of Nanoscience & Nanotechnology, vol. 13, no. 5, pp. 3354-3359.View/Download from: Publisher's site
Highly ordered mesoporous Co3O4 nanostructures were prepared using SBA-15 silica as hard templates. The mesoporous structures were characterized by X-ray diffraction, high resolution transmission electron microscopy, and N-2 adsorption/desorption isotherm analysis. The results demonstrated that the as-prepared mesoporous Co3O4 has an ordered P6mm symmetric mesoporous structure. The optical absorption properties of the mesoporous Co3O4 were investigated by UV-Vis spectroscopy and the results indicate that the mesoporous Co3O4 materials are semiconducting with direct band gaps of 2, 1.385 and 0.38 eV. The gas-sensing performance of the mesoporous Co3O4 was tested towards a series of typical solvents. They demonstrated a good sensing performance towards these vapour with rapid response and high sensitivity at low operating temperature.
Liu, H, Du, X, Xing, X, Wang, G & Qiao, S 2012, 'Highly ordered mesoporous Cr2O3 materials with enhanced performance for gas sensors and lithium ion batteries', Chemical Communications, vol. 48, no. 6, pp. 865-867.View/Download from: Publisher's site
Highly ordered mesoporous Cr2O3 materials with high specific surface area and narrow pore size distribution were successfully prepared by a vacuum assisted impregnation method. Both 2-dimensional hexagonal and 3-dimensional cubic Cr2O3 mesoporous replicas from SBA-15 and KIT-6 templates exhibit enhanced performance for gas sensors and lithium ion batteries, compared to the bulk Cr2O3 counterpart.
Sun, B, Liu, H, Munroe, P, Ahn, H & Wang, G 2012, 'Nanocomposites of CoO and a mesoporous carbon (CMK-3) as a high performance cathode catalyst for lithium-oxygen batteries', Nano Research, vol. 5, no. 7, pp. 460-469.View/Download from: Publisher's site
A nanocomposite of CoO and a mesoporous carbon (CMK-3) has been studied as a cathode catalyst for lithium-oxygen batteries in alkyl carbonate electrolytes. The morphology and structure of the as-prepared nanocomposite were characterized by field emission scanning electron microscopy, transmission electron microscopy and high resolution transmission electron microscopy. The electrochemical properties of the mesoporous CoO/CMK-3 nanocomposite as a cathode catalyst in lithium-oxygen batteries were studied using galvanostatic charge-discharge methods. The reaction products on the cathode were analyzed by Fourier transform infrared spectroscopy. The CoO/CMK-3 nanocomposite exhibited better capacity retention than bare mesoporous CMK-3 carbon, Super-P carbon or CoO/Super-P nanocomposite. The synergistic effects arising from the combination of CoO nanoparticles and the mesoporous carbon nanoarchitecture may be responsible for the optimum catalytic performance in lithium-oxygen batteries.
Liu, H, Su, D, Wang, G & Qiao, SZ 2012, 'An ordered mesoporous WS2 anode material with superior electrochemical performance for lithium ion batteries', Journal of Materials Chemistry, vol. 22, no. 34, pp. 17437-17440.View/Download from: Publisher's site
Ordered mesoporous tungsten sulfide (WS2) with high surface area and narrow pore size distribution was synthesized by a vacuum assisted impregnation route. The as-prepared mesoporous WS2 exhibited a high lithium storage capacity of 805 mA h g(-1) at a current of 0.1 A g(-1) and an excellent high rate capability.
Liu, H, Su, D, Zhou, R, Sun, B, Wang, G & Qiao, SZ 2012, 'Highly ordered mesoporous MoS2 with expanded spacing of the (002) crystal plane for ultrafast lithium ion storage', Advanced Energy Materials, vol. 2, no. 8, pp. 970-975.View/Download from: Publisher's site
Many alternative energy technologies have been developed in an attempt to alleviate the critical problems of an escalating energy crisis and greenhouse gas pollution, derived from the consumption of fossil fuels. Rechargeable lithium ion batteries have attracted great attention at fundamental application levels because of their high energy density and design fl exibility. As such, they are considered as the most promising next generation power sources for electric vehicles. The development of electric vehicles and hybrid electric vehicles demands high power energy sources which can operate under much higher current condition (tens of Amperes) than the operating current of mobilephones ( ~ 100 milli-Amperes).
Liu, H, Wang, G, Liu, J, Qiao, S & Ahn, H 2011, 'Highly ordered mesoporous NiO anode material for lithium ion batteries with an excellent electrochemical performance', Journal of Materials Chemistry, vol. 21, no. 9, pp. 3046-3052.View/Download from: Publisher's site
In this work, we have synthesized highly ordered mesoporous NiO materials by a nanocasting method using mesoporous silica KIT-6 as the hard templates. Mesoporous NiO particles were characterized by small angle X-ray diffraction (XRD), nitrogen adsorption/desorption, and transmission electron microscopy (TEM). The results demonstrated that the as-prepared mesoporous NiO had an ordered Ia3d symmetric mesostructure, with a high surface area of 96 m(2)/g. Mesoporous NiO materials were tested as an anode material for lithium ion batteries, exhibiting much lower activation energy (20.75 kJ mol(-1)) compared to the bulk NiO (45.02 kJ mol(-1)). We found that the mesoporous NiO electrode has higher lithium intercalation kinetics than its bulk counterpart. The specific capacity of mesoporous NiO after 50 cycles was maintained 680 mAh/g at 0.1 C, which was much higher than that of the commercial bulk NiO (188 mAh/g). Furthermore, at a high rate of 2C, the discharge capacity of mesoporous NiO was as high as 515 mAh/g, demonstrating the potential to be used for high power lithium ion batteries.
Wang, G, Liu, H, Liu, J, Qiao, S, Lu, GM, Munroe, P & Ahn, H 2011, 'ChemInform Abstract: Mesoporous LiFePO4/C Nanocomposite Cathode Materials for High Power Lithium Ion Batteries with Superior Performance.', ChemInform, vol. 42, no. 6, pp. no-no.View/Download from: Publisher's site
Chen, JS, Liu, H, Qiao, S & Lou, XW 2011, 'Carbon-supported ultra-thin anatase TiO2 nanosheets for fast reversible lithium storage', Journal of Materials Chemistry, vol. 21, no. 15, pp. 5687-5692.View/Download from: Publisher's site
This work reports a two-step method to synthesize carbon-supported ultrathin anatase TiO2 nanosheets (C-TiO2 NSs). Three samples with distinct structures were prepared via the assembly of these unique C-TiO2 NSs, including solid TiO2 hierarchical spheres and their hollow counterparts, as well as randomly-oriented C-TiO2 NSs. Specifically, the organic additive (diethylenetriamine) serves as both the capping agent during the initial solvothermal synthesis that stabilizes the (001) facets of anatase TiO2 and also the carbon source during the subsequent carbonization process. When evaluated for electrochemical lithium storage, all three samples assembled from carbon-supported anatase TiO2 NSs exhibit high reversible capacities with superior cyclic capacity retention at a high current rate. This enhanced lithium storage performance could be attributed to the ultrathin NS structure allowing efficient Li+ ion diffusion, as well as the effective nanocarbon support granting better structural stability. These findings suggest that carbon-supported TiO2 NSs may be used as a promising anode material for high-power lithium-ion batteries.
Liu, J, Qiao, S, Liu, H, Chen, J, Orpe, A, Zhao, D & Lu, GQ 2011, 'Extension of the stober method to the preparation of monodisperse resorcinol-formaldehyde resin polymer and carbon spheres', Angewandte Chemie International Edition, vol. 50, no. 26, pp. 5947-5951.View/Download from: Publisher's site
Sphere we go: Monodisperse resorcinol formaldehyde (RF) resin polymer spheres with finely tunable particle size ranging from 200 to 1000 nm (see pictures) are prepared by an extension of the Stöber method. Pyrolysis of the RF spheres at 600°C under N 2 atmosphere yields uniform carbon spheres with a volume shrinkage of 19%.
Novel nanosize SnO2 particles were synthesized by a hard template method. The crystal structure and morphologies were characterized by X-ray diffraction and transmission electron microscopy. The particle size is around 4 nm, which is less than two times the depth (L) of the of the surface depletion layer. The sensing properties towards a series of gases, including ethanol, isopropanol, 1-butanol, formaldehyde, acetic acid, acetone, and 92# gasoline, were tested at different gas concentrations. The results reveal that the SnO2 nanoparticles have high responsivity towards forementioned toxic and flammable gases.
Wang, G, Liu, H, Horvat, J, Wang, B, Qiao, S, Park, J & Ahn, H 2010, 'Highly Ordered Mesoporous Cobalt Oxide Nanostructures: Synthesis, Characterisation, Magnetic Properties, And Applications For Electrochemical Energy Devices', Chemistry: A European Journal, vol. 16, no. 36, pp. 11020-11027.View/Download from: Publisher's site
Highly ordered mesoporous Co3O4 nanostructures were prepared using KIT-6 and SBA-15 silica as hard templates. The structures were confirmed by small angle X-ray diffraction, high resolution transmission electron microscopy, and N-2 adsorption-desorption
Wang, G, Liu, H, Liu, J, Qiao, S, Lu, GM, Munroe, P & Ahn, H 2010, 'Mesoporous LiFePO4/C Nanocomposite Cathode Materials for High Power Lithium Ion Batteries with Superior Performance', Advanced Materials, vol. 22, no. 44, pp. 4944-4948.View/Download from: Publisher's site
Abstract: Hexagonally ordered mesoporous LiFePO4/C nanocomposites can be synthesized with LiFePO4 nanoparticles embedded in an interconnected carbon framework. Mesoporous LiFePO4/C nanocomposites exhibit superior electrochemical performance and ultra-high specific power density, which makes this architecture suitable for high power applications such as hybrid electric vehicles (HEVs) and stationary energy storage for smart grids.
Liu, H, Wang, G, Park, J, Wang, J, Liu, H & Zhang, C 2009, 'Electrochemical performance of alpha-Fe2O3 nanorods as anode material for lithium-ion cells', Electrochimica Acta, vol. 54, no. 6, pp. 1733-1736.View/Download from: Publisher's site
Alpha-Fe2O3 nanorods were synthesized by a facile hydrothermal method. The as-prepared alpha-Fe2O3 nanorods have a high quality crystalline nanostructure with diameters in the range of 6080 nm and lengths extending from 300 to 500 nm. The crystal structure of the alpha-Fe2O3 nanorods was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The alpha-Fe2O3 nanorod anodes exhibit a stable specific capacity of 800 mAh/g. This indicates significantly improved electrochemical performance in lithium-ion cells, compared to that of commercial microcrystalline alpha-Fe2O3 powders.
Liu, H, Wexler, D & Wang, G 2009, 'One-pot facile synthesis of iron oxide nanowires as high capacity anode materials for lithium ion batteries', JOURNAL OF ALLOYS AND COMPOUNDS, vol. 487, no. 1-2, pp. L24-L27.View/Download from: Publisher's site
Wang, B, Konstantinov, K, Wexler, D, Liu, H & Wang, G 2009, 'Synthesis of nanosized vanadium pentoxide/carbon composites by spray pyrolysis for electrochemical capacitor application', Electrochimica Acta, vol. 54, no. 5, pp. 1420-1425.View/Download from: Publisher's site
Nanostructured vanadium pentoxide/carbon (V2O5/carbon) composite powders with enhanced specific capacitance were synthesized by the spray pyrolysis technique. Electrochemical properties were examined by the cyclic voltammetry technique. Following analysis of powders sprayed at different temperatures, composite powders obtained at an optimum temperature of 450 °C yielded a maximum specific capacitance of 295 F g-1 in 2 M KCl electrolyte at a 5-mV s-1 scan rate. The weight percentage of carbon-related species was 2.7 wt% in this V2O5/carbon composite, as detected by thermogravimetric analysis (TGA) and confirmed by transmission electron microscope energy dispersive spectroscopy (TEM-EDS) analysis. Following initial X-ray diffraction (XRD) characterization, scanning electron microscope (SEM), TEM and high-resolution TEM (HRTEM) imaging revealed a specific morphology of spherical shell agglomerates of V2O5 nanorods and nanoribbons, with each shell comprising a network of these one- and two-dimensional nanoparticles in an amorphous carbon matrix. The V2O5 network was not fully dense, and the majority of the nanorod sizes were in the range of 50150 nm, with additional long nanoribbons extending from the outsides of the spherical shells. The specific surface area was 18 m2 g-1 for the composite powders, and the pore size distribution revealed that the majority of pores had diameters in the range of 4050 Å, which was relatively larger than the pore diameters obtained at 500 °C and would be beneficial for electrochemical performance. The enhancement of the specific capacitance in V2O5/carbon composites was attributed to the distribution of amorphous carbon throughout the V2O5 and the particular open nanostructure.
Wang, G, Shen, X, Horvat, J, Wang, B, Liu, H, Wexler, D & Yao, J 2009, 'Hydrothermal synthesis and optical, magnetic, and supercapacitance properties of nanoporous cobalt oxide nanorods', Journal of Physical Chemistry C, vol. 113, no. 11, pp. 4357-4361.View/Download from: Publisher's site
Nanoporous cobalt oxide nanorods were synthesized by a hydrothermal method. Transmission electron microscopy analysis showed that the individual Co3O4 nanorods have a nanoporous structure, consisting of the textured aggregations of nanocrystals. Optical properties of Co3O4 nanorods were characterized by Raman and UV-vis spectroscopy. Magnetic property measurement shows that Co3O4 nanorods have a low Nel transition temperature of 35 K. We observed quite significant exchange bias for nanoporous Co3O4 nanorods, indicating the existence of magnetic coupling between the nanocrystals in Co3O4 nanorods. When applied as electrode materials in supercapacitors, Co3O4 demonstrated a high capacitance of 280 F/g.
Wang, J, Chou, SL, Liu, H, Wang, G, Zhang, C, Chew, SY & Liu, H 2009, 'Highly flexible and bendable free-standing thin film polymer for battery application', Materials Letters, vol. 63, no. 27, pp. 2352-2354.View/Download from: Publisher's site
Highly flexible and bendable free-standing polypyrrole (PPy) films were prepared using the electrochemical polymerization method. The paper-like films are soft, lightweight, mechanically robust, and highly electrically conductive. The morphologies and electrochemical behaviour of the free-standing pure PPy films were affected by the electrochemical polymerization conditions. The free-standing films show promise as cathodes for flexible and bendable batteries
Yang, J, Wang, G, Liu, H, Park, J & Cheng, X 2009, 'Controlled synthesis and characterization of ZnSe nanostructures via a solvothermal approach in a mixed solution', Materials Chemistry And Physics, vol. 115, no. 1, pp. 204-208.View/Download from: Publisher's site
In the present study, ZnSe nanostructures with complex morphologies and different phase structures were synthesized via a solvothermal approach using a mixed solution of triethylenetetramine (TETA) and de-ionized water (DIW). It was found that the phase and morphology of the as-prepared products could be controlled by changing the volume ratio of TETA to DIW. Metastable ZnSe nanoflowers with layered structure could be obtained from pure TETA, which can be transformed to the wurtzite structure after heat-treating at 500 °C in Ar atmosphere. With the addition of DIW, the morphology changed from flowers to spheres, and when the volume ratio of TETA to DIW was 1:1, loose spheres composed of nanoparticles were obtained. Variation of the TETA content in the mixed solvent also allows controlling of the crystallographic phase of ZnSe (wurtzite or zinc blende). Both the as-prepared products and the annealed powders were systematically characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared absorbance spectroscopy (FTIR), thermogravimetric analysis (TGA), and ultravioletvisible (UVvis) spectroscopy methods.
Gou, X, Wang, G, Park, J, Liu, H & Yang, J 2008, 'Monodisperse hematite porous nanospheres: synthesis, characterization, and applications for gas sensors', NANOTECHNOLOGY, vol. 19, no. 12.View/Download from: Publisher's site
Liu, H, Wang, G, Wang, J & Wexler, D 2008, 'Magnetite/carbon core-shell nanorods as anode materials for lithium-ion batteries', Electrochemistry Communications, vol. 10, no. 12, pp. 1879-1882.View/Download from: Publisher's site
Carbon coated magnetite (Fe3O4) core-shell nanorods were synthesized by a hydrothermal method using Fe2O3 nanorods as the precursor. Transmission electron spectroscopy (TEM) and high resolution TEM (HRTEM) analysis indicated that a carbon layer was coated on the surfaces of the individual Fe3O4 nanorods. The electrochemical properties of Fe3O4/carbon nanorods as anodes in lithium-ion cells were evaluated by cyclic voltammetry, ac impedance spectroscopy, and galvanostatic charge/discharge techniques. The as-prepared Fe3O4/C core-shell nanorods show an initial lithium storage capacity of 1120 mAh/g and a reversible capacity of 394 mAh/g after 100 cycles, demonstrating better performance than that of the commercial graphite anode material.
Liu, H, Wang, G, Wexler, D, Wang, JZ & Liu, H 2008, 'Electrochemical performance of LiFePO4 cathode material coated with ZrO2 nanolayer', Electrochemistry Communications, vol. 10, no. 1, pp. 165-169.View/Download from: Publisher's site
ZrO2 nanolayer coated LiFePO4 particles were successfully prepared by a chemical precipitation method. Nanolayer structured ZrO2 was found on the surface of LiFePO4 particles by high resolution transmission electron microscopy (HRTEM). The coating does not affect the crystal structure of the LiFePO4 core, as determined by X-ray diffraction (XRD) and selected area electron diffraction (SAED) on individual particles. The ZrO2 coating can remarkably improve the electrochemical performance at high charge/discharge rate. This improvement may be due to the amelioration of the electrochemical dynamics on the LiFePO4 electrode/electrolyte interface resulting from the effects of the ZrO2 nanolayer coating.
Wang, G, Yang, J, Park, J, Gou, X, Wang, B, Liu, H & Yao, J 2008, 'Facile synthesis and characterization of Graphene nanosheets', Journal of Physical Chemistry C, vol. 112, no. 22, pp. 8192-8195.View/Download from: Publisher's site
Graphene nanosheets were produced in large quantity via a soft chemistry synthetic route involving graphite oxidation, ultrasonic exfoliation, and chemical reduction. X-ray diffraction and transmission electron microscopy (TEM) observations show that graphene nanosheets were produced with sizes in the range of tens to hundreds of square nanometers and ripple-like corrugations. High resolution TEM (HRTEM) and selected area electron diffraction (SAED) analysis confirmed the ordered graphite crystal structure of graphene nanosheets. The optical properties of graphene nanosheets were characterized by Raman spectroscopy
Yang, J, Wang, G, Liu, H, Park, J, Gou, X & Cheng, X 2008, 'Solvothermal synthesis and characterization of ZnSe nanoplates', Journal of Crystal Growth, vol. 310, no. 15, pp. 3645-3648.View/Download from: Publisher's site
ZnSe nanoplates were synthesized by a solvothermal method using ethylenediamine (EN) as the liganding solvent. The crystal structures, morphologies and optical properties of the precursor and ZnSe products were systematically characterized. Results reveal that precursor ZnSe(en)1/2 with a layered structure was initially obtained through solvothermal synthesis, which can be converted into hexagonal wurtzite structured ZnSe by heat-treatment in Ar atmosphere. The as-prepared ZnSe was composed of stacked nanoplates. The field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) results reveal that every nanoplate was made up of plenty of tiny single crystals. The room temperature ultravioletvisible (UV/vis) measurements indicate that the bandgap of the obtained ZnSe is 2.7 eV and a large blue shift about 1.3 eV was observed in precursor ZnSe(en)1/2.
Liu, H, Li, C, Cao, Q, Wu, YP & Holze, R 2008, 'Effects of heteroatoms on doped LiFePO4/C composites', Journal of Solid State Electrochemistry, vol. 12, pp. 1017-1020.View/Download from: Publisher's site
A series of supervalent cation doped Li(1-x) M(0.01)Fe(0.99)PO(4)/C composites (M=Ti, Zr, V, Nb, and W) were synthesized by solid-state reaction. The effects of the heteroatoms were studied by X-ray diffraction, cyclic voltammetry, and electrochemical impedance measurement. After doping, the lattice structure of LiFePO(4) is not destroyed and the reversibility of lithium ion intercalation and deintercalation is improved. The diffusion coefficient of lithium ions depends on the radius of the heteroatoms. As the radius of the heteroatom is larger, the diffusion coefficient increases.
Liu, H, Zhang, P, Li, GC, Wu, HQ & Wu, YP 2008, 'LiFePO4/C composites from carbothermal reduction method', Journal of Solid State Electrochemistry, vol. 12, pp. 1011-1015.View/Download from: Publisher's site
Using the cheap raw materials lithium carbonate, iron phosphate, and carbon, LiFePO4/C composite can be obtained from the carbothermal reduction method. X-ray diffraction (XRD) and scanning electronic microscope (SEM) observations were used to investigate the structure and morphology of LiFePO4/C.
Fu, LJ, Liu, H, Li, C, Wu, YP, Rahm, E, Holze, R & Wu, HQ 2006, 'Surface modifications of electrode materials for lithium ion batteries', Solid State Sciences, vol. 8, no. 2, pp. 113-128.View/Download from: Publisher's site
Since the birth of the lithium ion battery in the early 1990s, its development has been very rapid and it has been widely applied as power source for a lot of light and high value electronics due to its significant advantages over traditional rechargeable battery systems. Recent research demonstrates the importance of surface structural features of electrode materials for their electrochemical performance, and in this paper the latest progress on this aspect is reviewed. Electrode materials are either anodic or cathodic ones. The former mainly include graphitic carbons, whose surfaces can be modified by mild oxidation, deposition of metals and metal oxides, coating with polymers and other kinds of carbons. P, Through these modifications, the surface structures of the graphitic carbon anodes are improved, and these improvements include: (1) smoothing the active edge surfaces by removing some reactive sites and/or defects on the graphite surface, (2) forming a dense oxide layer on the graphite surface, and (3) covering active edge structures on the graphite surface. Meanwhile, other accompanying changes occur: (1) production of nanochannels/micropores, (2) an increase in the electronic conductivity, (3) an inhibition of structural changes during cycling, (4) a reduction of the thickness of the SEI (solid-electrolyte-interface) layer, and (5) an increase in the number of host sites for lithium storage.
Fu, LJ, Liu, H, Zhang, HP, Li, C, Zhang, T, Wu, YP & Wu, HQ 2006, 'Novel TiO2/C nanocomposites for anode materials of lithium ion batteries', Journal of Power Sources, vol. 159, no. 1, pp. 219-222.View/Download from: Publisher's site
Here we reported an effective method to prepare TiO2/C core-shell nanocomposites as active anode materials for lithium ion batteries with markedly ameliorated electrochemical performance. At first, a precursor, polyacrylonitrile coated nano-TiO2 particles, was formed by emulsion polymerization. Then the precursor was heat-treated under argon atmosphere to achieve the nanocomposites. The conductive carbon shell enveloped TiO2 nanoparticles and suppressed the aggregation of nanoparticles during cycling. Meanwhile, it combined closely with the nanocores, significantly enhanced kinetics of lithium intercalation and de-intercalation and diffusion coefficient of lithium ion. This provides a good way to improve the cycling and kinetics of nanoanode materials.
Fu, LJ, Liu, H, Zhang, HP, Li, C, Zhang, T, Wu, YP, Holze, R & Wu, HQ 2006, 'Synthesis and electrochemical performance of novel core/shell structured nanocomposites', Electrochemistry Communications, vol. 8, no. 1, pp. 1-4.View/Download from: Publisher's site
A new and effective method to prepare TiO2/C core-shell nanocomposites as active anode materials for lithium ion batteries with markedly ameliorated electrochemical performance is described. Initially a precursor, polyacrylonitrile coated nano-TiO2 particles, is formed by emulsion polymerization. This precursor is heat-treated under argon atmosphere to achieve the nanocomposite. The conductive carbon shell enveloped TiO2 nanoparticles and suppressed the aggregation of the core nanoparticles during cycling. In addition it is attached closely to the nano-cores, and the kinetics of lithium intercalation and de-intercalation, the apparent diffusion coefficient of lithium ions and the consequent cycling behavior are significantly enhanced. This provides a good way to improve cycling and kinetics of nano-anode materials
Li, C, Zhang, HP, Fu, LJ, Liu, H, Wu, YP, Rahm, E, Holze, R & Wu, HQ 2006, 'Cathode materials modified by surface coating for lithium ion batteries', Electrochimica Acta, vol. 51, no. 19, pp. 3872-3883.View/Download from: Publisher's site
Recent research results confirm the importance of structural surface features of cathode materials for their electrochemical performance. Modification by coating is an important method to achieve improved electrochemical performance, and the latest progress was reviewed here. When the surface of cathode materials including LiCoO2, LiNiO2, LiMn2O4 and LiMnO2 is coated with oxides such as MgO, Al2O3, SiO2, TiO2, ZnO, SnO2, ZrO2, Li2O center dot 2B(2)O(3)-glass and other materials, the coatings prevent the direct contact with the electrolyte solution, suppress phase transition, improve the structural stability, and decrease the disorder of cations in crystal sites. As a result, side reactions and heat generation during cycling are decreased. Accompanying actions such as suppression of Mn2+ dissolution, increase in conductivity and removal of HF in electrolyte solutions have been observed. Consequently, marked improvement of electrochemical performance of electrode materials including reversible capacity, coulomb efficiency in the first cycle, cycling behavior, rate capability and overcharge tolerance has been achieved. In conclusion, further directions are suggested for the surface modification of electrode materials. With further understanding of the effects of the surface structure of cathode materials on lithium intercalation and de-intercalation, better and/or cheaper cathode materials from surface modification will come up in the near future.
Liu, H, Cao, Q, Fu, LJ, Li, C, Wu, YP & Wu, HQ 2006, 'Doping effects of zinc on LiFePO4 cathode material for lithium ion batteries', Electrochemistry Communications, vol. 8, no. 10, pp. 1553-1557.View/Download from: Publisher's site
Alien atom doping has been adopted to modify the electrochemical performance of olivine type LiFePO4 for cathode material of the lithium ion batteries. Here, we first report that zinc-doping can improve the performance of LiFePO4. The effects of zinc-doping have been studied by the measurements of X-ray diffraction pattern, scanning electronic microscopy, electrochemical impedance spectroscopy and cyclic voltammetry. The results indicate that the zinc atoms do not destroy the lattice structure of LiFePO4, and enlarge the lattice volume. During de-intercalation and intercalation process of lithium ions, the doped zinc atoms protect the LiFePO4 crystal from shrinking. This kind of "pillar" effect provides larger space for the movement of lithium ions. Consequently, the conductivity is enhanced and the lithium ion diffusion coefficient is boosted after doping. These favourable changes are beneficial to the improvement of the electrochemical performance of LiFePO4 including discharge capacity and rate capability.
Liu, H, Fu, LJ, Zhang, HP, Gao, J, Li, C, Wu, YP & Wu, HQ 2006, 'Effects of carbon coatings on nanocomposite electrodes for lithium-ion batteries', ELECTROCHEMICAL AND SOLID STATE LETTERS, vol. 9, no. 12, pp. A529-A533.View/Download from: Publisher's site
Liu, H, Li, C, Zhang, HP, Fu, LJ, Wu, YP & Wu, HQ 2006, 'Kinetic study on LiFePO4/C nanocomposites synthesized by solid state technique', Journal of Power Sources, vol. 159, no. 1, pp. 717-720.View/Download from: Publisher's site
Well-crystallized, homogeneous nanocomposites of lithium iron(H) phosphate and carbon was synthesized by solid state reaction, and the obtained particles are spherical. Measurement of both CV and EIS shows that the lithium ion diffusion coefficient in the nanocomposites is affected by the incorporated carbon, and markedly increases with the carbon content. Meanwhile, the kinetics of lithium intercalation and de-intercalation is greatly ameliorated. These data provide strong evidence of the potential use of this kind of nanocomposite cathode in lithium ion battery.
Fu, LJ, Liu, H, Li, C, Wu, YP, Rahm, E, Holze, R & Wu, HQ 2005, 'Electrode materials for lithium secondary batteries prepared by sol-gel methods', Progress in Materials Science, vol. 50, no. 7, pp. 881-928.View/Download from: Publisher's site
Since the commercialization of lithium secondary batteries in the early of 1990s, their development has been rapid. Nowadays, improving the preparation technology and electrochemical performance of their electrode materials is a major focus in research and development of the materials, power sources and chemistry. Sol-gel methods are a promising way to prepare electrode materials due to their evident advantages over traditional methods, for example, homogeneous mixing at the atomic or molecular level, lower synthesis temperature, shorter beating time, better crystallinity, uniform particle distribution and smaller particle size at nanometer level. In this paper, latest progress in the preparation of electrode materials by sol-gel methods is reviewed, including cathodic ones, e.g., lithium cobalt oxides, lithium nickel oxides, spinel and layered lithium manganese oxides, vanadium oxides and ferrous phosphates, and anodic ones, e.g., tin oxides and titanium oxides. Compared with those prepared by traditional solid-state reaction, the structure stability of the prepared electrode materials and the behavior of lithium intercalation and de-intercalation are much improved. As a result, the prepared products provide better electrochemical performance including reversible capacity, cycling behavior and rate capability. In addition, sol-gel methods can be used to prepare new kinds of electrode materials such as nanowires of LiCoO2 and nanotubes of V2O5, which cannot be easily created by the traditional methods. Further development and application of sol-gel methods will bring about new and better electrode materials, meaning a great promotion to lithium secondary batteries.
Liu, H, Wu, YP, Rahm, E, Holze, R & Wu, HQ 2004, 'Cathode materials for lithium ion batteries prepared by sol-gel methods', Journal of Solid State Electrochemistry, vol. 8, no. 7, pp. 450-466.View/Download from: Publisher's site
Improving the preparation technology and electrochemical performance of cathode materials for lithium ion batteries is a current major focus of research and development in the areas of materials, power sources and chemistry. Sol-gel methods are promising candidates to prepare cathode materials owing to their evident advantages over traditional methods. In this paper, the latest progress on the preparation of cathode materials such as lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, vanadium oxides and other compounds by sol-gel methods is reviewed, and further directions are pointed out. The prepared products provide better electrochemical performance, including reversible capacity, cycling behavior and rate capability in comparison with those from traditional solid-state reactions. The main reasons are due to the following several factors: homogeneous mixing at the atomic or molecular level, lower synthesis temperature, shorter heating time, better crystallinity, uniform particle distribution and smaller particle size at the nanometer level. As a result, the structural stability of the cathode materials and lithium intercalation and deintercalation behavior are much improved. These methods can also be used to prepare novel types of cathode materials such as nanowires of LiCoO 2 and nanotubes of V 2O 5, which cannot be easily obtained by traditional methods. With further development and application of sol-gel methods, better and new cathode materials will become available and the advance of lithium ion batteries will be greatly promoted.
Liu, H, Sun, B & Wang, G 2016, 'Advances in Electrochemical Energy Materials and Technologies' in Electrochemical Energy Advanced Materials and Technologies, CRC Press, USA, pp. 33-53.View/Download from: Publisher's site
Greenhouse gas emissions from consumption of fossil fuels by traditional vehicles are
major causes of global warming and worldwide climate change. Rechargeable batteries are
widely considered as the promising power source for the next generation of electric vehicles
in order to relieve our reliance on fossil fuels. The lithium ion battery is well recognized as
the best choice among all different electrochemical power sources, such as fuel cells, solar
cells, lead-acid, Nickel-Cadmium and Nickel metal hydride batteries. The research and
development (R&D) on the lithium ion batteries has progressed rapidly since it was first
commercialized in the 1990s. Rechargeable lithium ion batteries have revolutionized portable
electronic devices and have become the dominant power source for mobile phones, laptop
computers and digital cameras because of their high energy density.[1,2] However, the
charge/discharge process in lithium ion batteries at high current rates can cause a high level
of polarization for bulk materials and degrade the electrochemical properties of the batteries.
The development of electric vehicles or hybrid electric vehicles demands high power
batteries, which can operate under high current conditions. In following sections, we will
briefly introduce advances in materials and technologies for lithium ion batteries and lithium
University of Wollongong, University of Queensland, Univeristy of Adelaide, Curtin University, Uniersity o Sydney, University of New outh Wales, Monash University, ANSTO, Fudan University, Shanghai University, Yanshan University, Beijing Institute of Technology, Gyeongsang National University, Nayang University of Technology, Jiangsu University etc.