为了研究Pr元素对La-Nd-Mg-Ni系贮氢合金相结构和电化学性能的影响,采用感应熔炼法制备了La0.20Nd0.60-xPrxMg0.20Ni3.20Co0.20Al0.20(x=0,0.10,0.20,0.30,0.40)合金.XRD分析表明,合金的主相为CaCu5型的LaNi5相和Ce2Ni7型的La2Ni7相.随着x的增大,两相的晶胞体积均增大,并且La2Ni7相的含量显著增加.P-C-T曲线表明,随着Pr含量的增加,合金氢化物的稳定性增强.电化学测试结果显示,随着Pr含量的增加,合金电极的高倍率放电性能、低温放电性能和循环稳定性均先提高后降低,其中100周循环容量保持率从76.7％(x=0)增加到88.7％ (x=0.30),然后又降低到82.3％ (x=0.40).%To investigate effect of rare earths on phase structure and electrochemical properties of La-Nd-Mg-Ni-based hydrogen storage alloys, La0.50Nd0.60-xPrxMg0.20Ni3.20Co0.20al0.20(x=0, 0.10, 0.20, 0.30, 0.40) alloys are prepared by inductive melting.XRD results show that main phases of the alloys are CaCu5-type LaNi5 phase and Ce2Ni7-type La2Ni7 phase.As x increases, the cell volume of the two phases increases and the content of La2Ni7 phase increases.P-C-T profiles show that stability of the hydrides increases with increasing Pr content.Electrochemical tests show that high rate dischargeability, low temperature dischargeability and cycling stability increases first and then decreases with increasing Pr content.The capacity retention rate at the 100th cycle increases from 76.7%(x=0) to 88.7%(x=0.30), and then decreases to 82.3%(x=0.40).
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