摘要
系统研究了V2.1TiNi0.4Zrx(x=0～0.06)储氢电极合金的相结构及电化学性能.相结构分析表明,所有合金均由体心立方(bcc)结构的V基固溶体主相和第二相组成,且第二相沿主相晶界形成三维网状分布;其中,当Zr含量x≤0.02时合金的第二相为TiNi基相,而当Zr含量x达0.04时,其第二相变为C14型Laves相,且主相和第二相的晶胞体积均随着x的增加而增大.电化学性能测试表明,添加Zr元素可以改善合金的活化性能和提高最大放电容量;同时,随着Zr含量x的增大,合金的高倍率放电性能得到明显提高,但充放电循环稳定性逐渐降低.在所研究的合金样品中,V2.1TiNi0.4Zr0.04合金具有相对较好的综合性能.
The phase structures and electrochemical properties of the V2.1TiNi0.4Zrx（x=0～0.06） hydrogen storage electrode alloys have been investigated. It is found that all the alloys consist of a main phase of V-based solid solution with a bcc structure and a secondary phase with a three-dimensional network structure. The secondary phase precipitates along the grain boundaries of the main phase. For the alloys with Zr content x ≤ 0.02, the secondary phase is the TiNi-based phase. As x reaches 0.04, the secondary phase changes into the Cl4-type Laves phase. Moreover, the unit cells of both the main phase and the secondary phase expand with the increasing Zr content. Electrochemical measurements show that activation behavior and maximum discharge capacities of the Zr-added alloy are better than those of V2.1TiNi0.4 alloy. As the Zr content in the alloy increases, their high-rate dischargeability is improved significantly, but their cycle stability degrades gradually. For the alloy with the Zr content of x-=0.04, the best overall electrochemical performances are obtained.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2006年第5期523-527,共5页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(50271064
50571089)资助项目
关键词
储氢电极合金
相结构
电化学性能
V基固溶体
Hydrogen storage electrode alloy, Phase structure, Electrochemical property, V-based solid solution
