Effect of La/Mg on the structure and electrochemical performance of La–Mg–Ni system hydrogen storage electrode alloy
Effect of La/Mg on the structure and electrochemical performance of La–Mg–Ni system hydrogen storage electrode alloy
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DOI：
10.1016/j.matchemphys.2007.09.028
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发表时间：
2008-04
影响因子：
4.6
通讯作者：
Xiaoping Dong;Fanxiu Lü;Yang-Huang Zhang;Liying Yang;Xin-lin Wang
中科院分区：
文献类型：
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作者：
Xiaoping Dong;Fanxiu Lü;Yang-Huang Zhang;Liying Yang;Xin-lin Wang
为了提高La-Mg-Ni系（A2B7型）合金电极的电化学性能，详细研究了La/Mg比例对合金结构和电化学性能的影响。从X射线衍射分析来看，每种合金均由LaNi5、(La,Mg)2Ni7和少量LaNi2相组成。然而，当La/Mg比大于3时，LaMg相出现，并且LaMg相的量随着La/Mg比的增加而增加。随着La/Mg比例的增加，合金的放电容量降低，在900mAg−1放电倍率下，合金电极的HRD900从77.96%（La/Mg=3）下降到61.01%（La/Mg=17/3），合金电极的电荷转移电阻和极化电阻增大，合金的极限电流密度IL增加 电极减少。经过100次充放电循环后，随着La/Mg比值的增加，合金的循环稳定性从55.83%（La/Mg=3）提高到67.36%（La/Mg=17/3）。
In order to improve the electrochemical performances of La–Mg–Ni system (A2B7-type) alloy electrodes, the effects of La/Mg ratio on structures and electrochemical performances of the alloys were investigated in detail. From the XRD analyses, each alloy is composed of the LaNi5, (La, Mg)2Ni7and a few LaNi2phases. However, when La/Mg ratio is more than 3, the LaMg phase appears, and the amount of the LaMg phase increases with the increase of La/Mg ratio. With increasing of La/Mg ratio, the discharge capacities of the alloys decrease, the HRD900of the alloy electrodes decrease from 77.96% (La/Mg=3) to 61.01% (La/Mg=17/3) at the discharge rate of 900mAg−1, charge-transfer resistance and polarization resistance of the alloy electrodes increase, the limiting current densities ILof the alloy electrodes decrease. The cycling stabilities of the alloys enhance from 55.83% (La/Mg=3) to 67.36% (La/Mg=17/3) with the increase of La/Mg ratio after 100charge/discharge cycles.