中文摘要：

采用X射线衍射、电子探针和电化学测试研究了La2MgNi7.5-xCo1．5Alx（x=0．0～0．5）合金的相结构和电化学性能。XRD结果和EPMA观察表明，Al替代改变了合金的物相组成和物相的丰度。LaNi3相消失，αLa2Ni7相丰度的变化表现为先增加（x从0．0-0．1）后减少（x=0．3和0．5），LaNi5相随合金中Al含量x的增加而明显增加。Al替代Ni降低了合金的最大电化学放电容量和活化性能，但明显改善了La2MgNi7．5Co1．5合金的电化学循环稳定性。

英文摘要：

Phase structure and electrochemical properties of La2MgNi7.5-xC01.5 Alx （x=0. 0-0. 5） alloys were investigated by means of X-ray diffraction （XRD）, electron probe X-ray microanalysis （EPMA） and electrochemical measurements. XRD and EPMA results show that Al substitution for Ni change phase composition and phase abundance of the alloys. LaNi3 phase disappeared, the abundance of αLa2Ni7 first increases when Al content from x=0.0 to x=0. 1 and then decreases （x=0.3 and 0. 5）. Abundance of LaNi5 phase increase obviously as Al content x increase in the alloys. Replacement of Ni by Al lower maximum electrochemical discharge capacity and activation property the alloy electrodes. But Al substitution can improve obviously electrochemical cyclic stability of La2MgN7.5Co 1.5 alloy electrode.