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用冷坩埚磁悬浮熔炼方法制备La0.5Mg0.5(Ni1-xCox)2.28(x=0.0～0.2)贮氢电极合金,采用SEM,EDS,XRD,P-C-T测试及三电极电化学性能测试研究合金的相成分、相结构、P-C-T曲线和电化学性能。EDS结合XRD分析表明,La0.5Mg0.5Ni2.28及La0.5Mg0.5(Ni0.85Co0.15)2.28合金主相均为MgSnCu4型的LaMgNi4相,还包括LaNi5和(La,Mg)Ni3相。P-C-T曲线显示,合金均有双放氢平台,合金的贮氢量由Co替代量x=0.0时的1.24%增大至极大值x=0.15时的1.27%。电化学性能测试表明,随Co含量增加,最大放电容量从329.0mAh.g-1(x=0.0)增大到337.5mAh.g-1(x=0.15),合金活化性能及高倍率放电性能明显改善;循环稳定性无明显变化。
The La0.5Mg0.5 (Ni1-xCox) 2.28 (x = 0.0-0.2) hydrogen storage electrode alloy was prepared by cold crucible magnetic levitation melting. The phase of the alloy was studied by SEM, EDS, XRD, PCT and electrochemical tests Composition, Phase Structure, PCT Curve and Electrochemical Properties. EDS combined with XRD analysis showed that the main phase of La0.5Mg0.5Ni2.28 and La0.5Mg0.5 (Ni0.85Co0.15) 2.28 alloy are all LaMgNi4 phase of MgSnCu4 type, and LaNi5 and (La, Mg) Ni3 phase. P-C-T curves show that the alloy has a double-drop platform. The hydrogen storage capacity of the alloy increases from 1.24% when the amount of Co substitution is x = 0.0 to 1.27% when the maximum is x = 0.15. The results of electrochemical tests show that the maximum discharge capacity increases from 329.0mAh.g-1 (x = 0.0) to 337.5mAh.g-1 (x = 0.15) with the increase of Co content. Improve; no significant change in cycle stability.