Enhanced electrochemical properties of Ti1.4V0.6Ni with Mo2C or WC coating as negative electrodes for Ni-MH battery

Composites of Ti1.4V0.6Ni coated with Mo2C or WC are prepared through ball milling, and their electrochemical properties are investigated as negative electrode materials in a Ni-MH battery system. Mo2C and WC disperse adequately on the surface of the Ti1.4V0.6Ni alloy to form Ti1.4V0.6Ni@Mo2C and Ti1.4V0.6Ni@WC, respectively. The composites exhibit higher electrochemical hydrogen storage capacity and more stable cycling stability than the bare alloy. Particularly, the capacity conservation rate of Ti1.4V0.6Ni@WC is 67.4% after 200 cycles, and it increases by 29.5% compared with Ti1.4V0.6Ni alloy. A study of the kinetics demonstrates that Mo2C or WC coating accelerates the charge-transfer reaction and increases the electrochemical activity of the Ti1.4V0.6Ni electrode. The improvements to electrochemical properties of Ti1.4V0.6Ni may be due to the proper Mo2C or WC coating with copacetic electrocatalytic activity and anti-pulverization ability. (C) 2016 Elsevier B.V. All rights reserved.