Influence of the substitution Ce for La on structural and electrochemical characteristics of La0.75-xCexMg0.25Ni3Co0.5 (x=0, 0.05, 0.1, 0.15, 0.2 at. %) hydrogen storage alloys
Influence of the substitution Ce for La on structural and electrochemical characteristics of La0.75-xCexMg0.25Ni3Co0.5 (x=0, 0.05, 0.1, 0.15, 0.2 at. %) hydrogen storage alloys
复制标题
影响%20of%20%20替代%20Ce%20为%20La%20on%20结构%20和%20电化学%20特性%20of%20La0.75-xCexMg0.25Ni3Co0.5%20(x=0,%200.05,%200.1,%200.15
DOI：
10.1016/j.jallcom.2017.09.300
复制
发表时间：
2018
影响因子：
6.2
通讯作者：
Wu Ying
中科院分区：
文献类型：
--
作者：
Lv Wei;Yuan Jianguang;Zhang Bao;Wu Ying
研究了在氦气气氛下感应熔炼，1173℃真空退火8h制备的La0.75-xCexMg0.25Ni3Co0.5(x=0.05，0.1，0.15，0.2at.%)合金的结构和电化学性能。由X射线衍射数据得到的Rietveld细化结果表明，合金主要由(La，Mg)Ni3，(La，Mg)2Ni7和LaNi5相组成。随着Ce含量的增加，(La，Mg)Ni3相和(La，Mg)2Ni7相的数量减少，而LaNi5相的数量增加。电化学性能测试结果表明，La0.75-xCexMg0.25Ni3Co0.5合金在2次循环内完全活化，随着Ce含量的增加，合金100次充放电循环稳定性从62.39%提高到84.94%，当Ce含量为0.1%时，100次循环的放电容量达到最大值259 mAh/g。同时，合金电极的高倍率放电能力在Ce含量为0.1at.%时达到最大值，然后下降。因此，La0.65Ce0.1Mg0.25Ni3Co0.5合金具有最佳的综合电化学性能。
Structural and electrochemical performances of La0.75-xCexMg0.25Ni3Co0.5(x = 0, 0.05, 0.1, 0.15, 0.2 at.%) alloys prepared by an induction melting under helium atmosphere followed by annealing treatment at 1173 K in a vacuum furnace for 8 h are studied. Rietveld refinement results from the XRD data suggest that the alloys are mainly composed of (La, Mg)Ni3, (La, Mg)2Ni7and LaNi5phases. Increasing the content of Ce, the amounts of (La, Mg)Ni3phase and (La, Mg)2Ni7phase decrease, while the amount of LaNi5phase increases. Electrochemical performance measurement results show that the La0.75-xCexMg0.25Ni3Co0.5alloys are completely activated within 2 cycles, and the cyclic stability after 100 charge/discharge cycles of the alloys increases from 62.39% to 84.94% with the rising of Ce content, and the discharge capacity of the 100thcycle reaches the maximum value of 259 mAh/g when Ce content is 0.1 at.%. Meanwhile, the high rate discharge ability of the alloy electrodes increases to the maximum value when Ce content is 0.1 at.%, and then decreases. Thus, the La0.65Ce0.1Mg0.25Ni3Co0.5alloy exhibits optimum comprehensive electrochemical properties.