A new strategy to improve the high-rate performance of hydrogen storage alloys with MoS2 nanosheets

作者：Chen, L. X.; Zhu, Y. F.; Yang, C. C.^*; Chen, Z. W.; Zhang, D. M.; Jiang, Q.^*

来源：Journal of Power Sources, 2016, 333: 17-23.

DOI：10.1016/j.jpowsour.2016.09.148

• Hydrogen storage alloy
• MoS2 nanosheet
• High-rate dischargeability
• Nickel metal hydride battery

The poor high-rate dischargeability of negative electrode materials (hydrogen storage alloys) has hindered applications of nickel metal hydride batteries in high-power fields, new-energy vehicles, power tools, military devices, etc. In this work, a new strategy is developed to improve the high-rate performance of hydrogen storage alloys by coating MoS2 nanosheets on alloy surfaces. The capacity retention rate of the composite electrode reaches 50.5% at a discharge current density of 3000 mA g(-1), which is 2.7 times that. of bare alloy (18.4%). The density functional theory simulations indicate that such an outstanding performance is derived from adjustments of ion concentrations at the electrode/electrolyte interface by MoS2 nanosheets: (1) the higher OH- concentration facilitates the electrochemical reaction of MHads + OH- -> e(-) -> M + H2O;.and (2) the lower H+ concentration leads to a large gradient between the electrode/electrolyte interface and interior of alloys, which is beneficial for the diffusion of atomic hydrogen during the discharging process.

• 出版日期2016-11-30
• 单位吉林大学