Zhang, J, Sade, H, Zhao, Y, Murdock, AT, Bendavid, A, Lellouche, J-P, Wang, G & Han, Z 2019, 'Conformal carbon coating on WS2 nanotubes for excellent electrochemical performance of lithium-ion batteries.', Nanotechnology, vol. 30, no. 3, pp. 035401-035401.View/Download from: UTS OPUS or Publisher's site
WS2 nanotubes with carbon coatings in a core-shell structure (i.e. WS2@C) are synthesized through a facile method based on the Lewis acid-activated thioglycosylation chemistry. The obtained WS2@C shows a conformal coverage of conductive amorphous carbon on the surface of WS2 after thermal treatment, with the thickness of carbon layer being controlled by adjusting the molar ratios of saccharide to nanotube during the synthesis process. When applied in lithium-ion batteries, the WS2@C structures show higher reversible capacity of 638 mAh g-1 at a current density of 500 mA g-1 and significantly improved cycling stability as compared to the pristine WS2 nanotubes. Post-mortem examinations of the electrode materials reveal that the carbon coatings could preserve the morphology of WS2 nanotubes and assist in forming stable solid electrolyte interface layers, leading to enhanced cycling stability. As such, the WS2@C structures show great potential in the application of lithium-ion batteries for achieving excellent electrochemical performances.
Zhang, J, Sun, B, Zhao, Y, Tkacheva, A, Liu, Z, Yan, K, Guo, X, McDonagh, AM, Shanmukaraj, D, Wang, C, Rojo, T, Armand, M, Peng, Z & Wang, G 2019, 'A versatile functionalized ionic liquid to boost the solution-mediated performances of lithium-oxygen batteries.', Nature communications, vol. 10, no. 1.View/Download from: UTS OPUS or Publisher's site
Due to the high theoretical specific energy, the lithium-oxygen battery has been heralded as a promising energy storage system for applications such as electric vehicles. However, its large over-potentials during discharge-charge cycling lead to the formation of side-products, and short cycle life. Herein, we report an ionic liquid bearing the redox active 2,2,6,6-tetramethyl-1-piperidinyloxy moiety, which serves multiple functions as redox mediator, oxygen shuttle, lithium anode protector, as well as electrolyte solvent. The additive contributes a 33-fold increase of the discharge capacity in comparison to a pure ether-based electrolyte and lowers the over-potential to an exceptionally low value of 0.9 V. Meanwhile, its molecule facilitates smooth lithium plating/stripping, and promotes the formation of a stable solid electrolyte interface to suppress side-reactions. Moreover, the proportion of ionic liquid in the electrolyte influences the reaction mechanism, and a high proportion leads to the formation of amorphous lithium peroxide and a long cycling life (> 200 cycles). In particular, it enables an outstanding electrochemical performance when operated in air.
Zhang, J, Zhao, Y, Guo, X, Chen, C, Dong, CL, Liu, RS, Han, CP, Li, Y, Gogotsi, Y & Wang, G 2018, 'Single platinum atoms immobilized on an MXene as an efficient catalyst for the hydrogen evolution reaction', Nature Catalysis, vol. 1, no. 12, pp. 985-992.View/Download from: UTS OPUS or Publisher's site
© 2018, The Author(s), under exclusive licence to Springer Nature Limited. Single-atom catalysts offer a pathway to cost-efficient catalysis using the minimal amount of precious metals. However, preparing and keeping them stable during operation remains a challenge. Here we report the synthesis of double transition metal MXene nanosheets—Mo 2 TiC 2 T x , with abundant exposed basal planes and Mo vacancies in the outer layers—by electrochemical exfoliation, enabled by the interaction between protons and the surface functional groups of Mo 2 TiC 2 T x . The as-formed Mo vacancies are used to immobilize single Pt atoms, enhancing the MXene's catalytic activity for the hydrogen evolution reaction. The developed catalyst exhibits a high catalytic ability with low overpotentials of 30 and 77 mV to achieve 10 and 100 mA cm −2 and a mass activity about 40 times greater than the commercial platinum-on-carbon catalyst. The strong covalent interactions between positively charged Pt single atoms and the MXene contribute to the exceptional catalytic performance and 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: UTS OPUS or 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.
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: UTS OPUS or 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.
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: UTS OPUS or Publisher's site
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: UTS OPUS or 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: UTS OPUS or 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.
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: UTS OPUS or 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.
Zhang, J, Sun, B, McDonagh, AM, Zhao, Y, Kretschmer, K, Guo, X & Wang, G 2017, 'A multi-functional gel co-polymer bridging liquid electrolyte and solid cathode nanoparticles: An efficient route to Li–O2batteries with improved performance', Energy Storage Materials, vol. 7, pp. 1-7.View/Download from: UTS OPUS or Publisher's site
© 2016 Lithium-oxygen (Li–O 2 ) batteries have the highest theoretical energy density amongst all rechargeable batteries and have attracted significant attention. However, large over-potentials originating from sluggish reaction kinetics often lead to low round-trip energy efficiency and short cycle life. We report here a novel multi-functional gel co-polymer that efficiently enhances the discharge and charge performances in Li–O 2 batteries by intimately connecting the liquid electrolyte and solid cathode nanoparti cles. On one hand, the co-polymer material, poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate-co-methyl methacrylate) (P(TMA-MMA)), functions as a binder during the fabrication of the cathode and forms a gel polymer membrane to retain liquid electrolyte and to increase ionic conductivity. On the other hand, the TMA units, containing N–O radical groups that catalyse Li 2 O 2 formation and decomposition during charge and discharge cycles, are distributed throughout the polymer membrane. This allows more effective formation and decomposition of Li 2 O 2 than surface bound catalytic units. The combination of gelable MMA and catalytic TMA moieties enhances the interface between liquid electrolyte and solid cathode by functioning as a medium both to transport Li + (enhancing discharge process) and to carry electrons (reducing charge over-potential). Consequently, the optimized P(TMA-MMA) co-polymers provide exceptional electrochemical performance in Li–O 2 batteries.
Zhang, J, Sun, B, Zhao, Y, Kretschmer, K & Wang, G 2017, 'Modified Tetrathiafulvalene as an Organic Conductor for Improving Performances of Li−O 2 Batteries', Angewandte Chemie, vol. 129, no. 29, pp. 8625-8629.View/Download from: UTS OPUS or Publisher's site
Large over‐potentials owing to the sluggish kinetics of battery reactions have always been the drawbacks of Li−O2 batteries, which lead to short cycle life. Although redox mediators have been intensively investigated to overcome this issue, side‐reactions are generally induced by the solvated nature of redox mediators. Herein, we report an alternative method to achieve more efficient utilization of tetrathiafulvalene (TTF) in Li−O2 batteries. By coordinating TTF+ with LiCl during charging, an organic conductor TTF+Clx− precipitate covers Li2O2 to provide an additional electron‐transfer pathway on the surface, which can significantly reduce the charge over‐potential, improve the energy efficiency of Li−O2 batteries, and eliminate side‐reactions between the lithium metal anode and TTF+. When a porous graphene electrode is used, the Li−O2 battery combined with TTF and LiCl shows an outstanding performance and prolonged cycle life.
Zhang, J, Sun, B, Zhao, Y, Kretschmer, K & Wang, G 2017, 'Modified Tetrathiafulvalene as an Organic Conductor for Improving Performances of Li-O2 Batteries.', Angewandte Chemie, vol. 56, no. 29, pp. 8505-8509.View/Download from: UTS OPUS or Publisher's site
Large over-potentials owing to the sluggish kinetics of battery reactions have always been the drawbacks of Li-O2 batteries, which lead to short cycle life. Although redox mediators have been intensively investigated to overcome this issue, side-reactions are generally induced by the solvated nature of redox mediators. Herein, we report an alternative method to achieve more efficient utilization of tetrathiafulvalene (TTF) in Li-O2 batteries. By coordinating TTF+ with LiCl during charging, an organic conductor TTF+ Clx- precipitate covers Li2 O2 to provide an additional electron-transfer pathway on the surface, which can significantly reduce the charge over-potential, improve the energy efficiency of Li-O2 batteries, and eliminate side-reactions between the lithium metal anode and TTF+ . When a porous graphene electrode is used, the Li-O2 battery combined with TTF and LiCl shows an outstanding performance and prolonged cycle life.
Xu, J, Su, D, Bao, W, Zhao, Y, Xie, X & Wang, G 2016, 'Rose flower-like NiCo2O4 with hierarchically porous structures for highly reversible lithium storage', JOURNAL OF ALLOYS AND COMPOUNDS, vol. 684, pp. 691-698.View/Download from: Publisher's site
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
Zhang, J, Sun, B, Xie, X, Zhao, Y & Wang, G 2016, 'A Bifunctional Organic Redox Catalyst for Rechargeable Lithium-Oxygen Batteries with Enhanced Performances', ADVANCED SCIENCE, vol. 3, no. 4.View/Download from: UTS OPUS or 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: UTS OPUS or 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: UTS OPUS or 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.
Chen, S, Zhao, Y, Sun, B, Ao, Z, Xie, X, Wei, Y & Wang, G 2015, 'Microwave-assisted Synthesis of Mesoporous Co3O4 Nanoflakes for Applications in Lithium Ion Batteries and Oxygen Evolution Reactions', ACS APPLIED MATERIALS & INTERFACES, vol. 7, no. 5, pp. 3306-3313.View/Download from: UTS OPUS or Publisher's site
Kretschmer, K, Sun, B, Su, D, Zhao, Y & Wang, G 2015, 'Scalable Preparation of LiFePO4/C Nanocomposites with sp(2)-Coordinated Carbon Coating as High-Performance Cathode Materials for Lithium-Ion Batteries', CHEMELECTROCHEM, vol. 2, no. 12, pp. 2096-2103.View/Download from: UTS OPUS or Publisher's site
Zhao, Y-F, Yang, Z-Y, Zhang, Y-X, Jing, L, Guo, X, Ke, Z, Hu, P, Wang, G, Yan, Y-M & Sun, K-N 2014, 'Cu2O Decorated with Cocatalyst MoS2 for Solar Hydrogen Production with Enhanced Efficiency under Visible Light', JOURNAL OF PHYSICAL CHEMISTRY C, vol. 118, no. 26, pp. 14238-14245.View/Download from: UTS OPUS or Publisher's site
Huang, X, Zhao, Y, Ao, Z & Wang, G 2014, 'Micelle-Template Synthesis of Nitrogen-Doped Mesoporous Graphene as an Efficient Metal-Free Electrocatalyst for Hydrogen Production', SCIENTIFIC REPORTS, vol. 4.View/Download from: UTS OPUS or Publisher's site
Sun, B, Huang, X, Chen, S, Zhao, Y, Zhang, J, Munroe, P & Wang, G 2014, 'Hierarchical macroporous/mesoporous NiCo2O4 nanosheets as cathode catalysts for rechargeable Li-O2 batteries', Journal of Materials Chemistry A, vol. 2, pp. 12053-12059.View/Download from: UTS OPUS or Publisher's site
The key factor to improve the electrochemical performance of Li-O2 batteries is to find bi-functional cathode catalysts to promote the oxygen reduction and evolution reactions. Despite tremendous effects, developing cathode catalysts with high activity remains a great challenge. Herein, we report the synthesis of hierarchical macroporous/mesoporous NiCo2O4 nanosheets as an effective cathode catalyst for Li-O2 batteries. The hierarchical porous catalyst was synthesized by a hydrothermal method, followed by low temperature calcination. SEM and TEM observations clearly present that the as-prepared NiCo2O4 nanosheets showed a hierarchical porous structure with mesopores distributed through the surface of NiCo2O4 nanosheets and macropores formed between the crumpled nanosheets. When investigating as the cathode catalyst in Li-O2 batteries, the as-prepared NiCo2O4 nanosheets exhibited higher reversible capacity, lower charge/discharge overpotential, and better cycling stability than those of pristine carbon black. The enhanced electrochemical performance of NiCo2O4 nanosheets should be attributed not only to the high catalytic activity of NiCo2O4 towards oxygen reduction reaction and oxygen evolution reaction, but also to the novel hierarchical porous structure of NiCo2O4.