V2.1TiNi0.4Zr0.06Cux(x=0-0.12)储氢合金的微结构及电化学性能

采用磁悬浮感应熔炼方法制备了V2.1TiNi0.4Zr0.06Cux (x=0-0.12)储氢合金, 经XRD、SEM、EDS和电化学测试等系统研究了Cu添加量对合金微结构及电化学性能的影响. 结果表明, 所有合金均由V基固溶体主相和C14型Laves第二相组成, 且第二相沿主相晶界形成三维网状分布; 合金主相和第二相的晶胞体积均随着Cu含量x的增加而增大. 电化学性能测试表明, 添加适量(x=0.03-0.06)的Cu可以提高合金的最大放电容量, 并对活化性能基本没有影响; 而过高的Cu添加量(x≥0.09)会降低合金的放电容量. 此外, 添加Cu可使合金的高倍率放电性能得到明显改善, 充放电循环稳定性有所提高. 在所研究的合金样品中, V2.1TiNi0.4Zr0.06Cu0.03合金具有最佳的综合性能.

Microstructure and Electrochemical Properties of V2.1TiNi0.4Zr0.06Cux (x=0-0.12) Hydrogen Storage Alloys

V2.1TiNi0.4Zr0.06Cux (x=0-0.12) hydrogen storage alloys were prepared by induction melting with magnetic levitation, and the effects of Cu content on the microstructure and electrochemical properties of the alloys were investigated by XRD, SEM, EDS, and electrochemical test. It was found that all the alloys was consisted of a V-based solid solution main phase and a C14-type Laves secondary phase in the form of three-dimensional network. The secondary phase precipitates along the grain boundaries of the main phase. The unit cells of both main phase and secondary phase expand with increasing Cu content. The results showed that the maximum discharge capacity was improved and the activation behavior was invariable as some Cu (x=0.03-0.06) was added into the V2.1TiNi0.4Zr0.06 alloy. However, higher Cu content (x≥0.09) in the alloy impairs the discharge capacity. Furthermore, adding Cu into the V2.1TiNi0.4Zr0.06 alloy can improve its cycling stability and high-rate dischargeability significantly.