V2Ti0.5Cr0.5Ni1-xMnx（x=0.05～0.2）储氢合金结构和电化学性能研究

Investigation on the Structures and Electrochemical Properties of V2Ti0.5Cr0.5Ni1-xMnx（x=0.05～0.2）Hydrogen Storage Alloys

为了研究V基储氢材料的结构和电化学性能,采用真空感应电弧炉熔炼了V2Ti0.5Cr0.5Ni1-xMnx(x=0.05~0.2)储氢合金,并分析该储氢合金电极的微观形貌和电化学性能。结果表明,储氢合金主要由体心立方(BCC)结构的钒基固溶体主相和部分TiNi第二相构成。电化学测试表明,当合金电极中Mn替代Ni的量逐渐增加,储氢合金电极的高倍率放电性能、最大放电容量和交换电流密度逐渐增大,当x=0.2时,合金放电容量最大值为429.3 mAh/g,高倍率放电性能为55%,交换电流密度为52 mA/g,而储氢合金电极的循环稳定性能降低。

V2Ti0.5Cr0.5Ni1-xMnx(x=0.05~0.2)hydrogen storage alloys were prepared by vacuum induction arc-melting,and the microstructure and electrochemical properties of the alloys were investigated systematically.The results show that the alloys mainly consist of a V-based solid solution phase with a BCC structure and a TiNi-based secondary phase.The electrochemical tests indicate that with increase of Mn content in the alloys,the high-rate discharge capability,maximum discharge capacity and exchange current density of the alloys increase gradually.The maximum discharge capacity of 429.3 mAh/g,high-rate discharge capability of 55% and exchange current density of 52 mA/g can be obtained for the alloy at x=0.2,with the electrochemical kinetics improved but the cycling stability weakened.