论文部分内容阅读
采用X射线衍射技术(XRD)、电池程控测试仪和电化学工作站等技术手段,研究了少量Mo替换Ni对La0.75-Mg0.25Ni3.5-xMox(x=0~0.5,原子分数/%,下同)贮氢电极合金相结构及电化学性能的影响。结果表明:La0.75Mg0.25-Ni3.5-xMox合金具有多相结构,主相由Gd2Ni7型结构的La2Ni7和CaCu5型结构的LaNi5构成,合金活化性能良好,经过4次充放电过程基本都能达到活化状态。当Mo的加入量达到0.3%时,合金中出现MoNi4,且La2Ni7和LaNi5的点阵参数随之增大;合金的高倍率放电(HRD)性能显著提高,HRDI=900mA/g由82.58%(x=0)增加到86.72%(x=0.5);循环稳定性能(S100)也得到较大改善,呈现先增加后降低的变化趋势,x=0.3时循环稳定性能最好,S100达到76.61%,但合金的最大放电比容量(Cmax)逐渐降低。
The effect of a small amount of Mo substitution on La0.75-Mg0.25Ni3.5-xMox (x = 0 ~ 0.5, atomic fraction /%) has been investigated by X-ray diffraction (XRD), cell programmed tester and electrochemical workstation. , The same below) hydrogen storage electrode alloy phase structure and electrochemical properties. The results show that the La0.75Mg0.25-Ni3.5-xMox alloy has a multi-phase structure. The main phase is composed of La2Ni7 of Gd2Ni7 type and LaNi5 of CaCu5 type. The activation properties of La0.75Mg0.25-Ni3.5-xMox alloy are good. After 4 cycles of charging and discharging, La0.75Mg0.25- Reach the activation state. When the content of Mo is 0.3%, MoNi4 is present in the alloy, and the lattice parameters of La2Ni7 and LaNi5 increase. The HRD of the alloy increases remarkably with HRDI = 900mA / g from 82.58% (x = 0) increased to 86.72% (x = 0.5). The cycle stability (S100) also improved greatly, showing a trend of first increasing and then decreasing. At x = 0.3, the cycle stability was the best, with S100 reaching 76.61% The maximum discharge capacity of alloy (Cmax) gradually decreased.