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采用X射线衍射、电子探针和电化学测试研究了La0.67Mg0.33Ni3.0-xAlx(x=0.0～0.35)合金的相结构和电化学性能。XRD结果和EPMA观察表明:La0.67Mg0.33Ni3.0合金由LaNi3相和La2Ni7相组成。然而La0.67Mg0.33Ni3.0-xAlx(x=0.1,0.2,0.35)合金不含LaNi3相。研究结果表明Al替代Ni改变了La0.67Mg0.33Ni3.0合金的相结构,Al替代Ni不利于La0.67Mg0.33Ni3.0合金中LaNi3相的形成。此外,随Al含量的增加,La0.67Mg0.33Ni3.0-xAlx(x=0.1,0.2,0.35)合金的相结构也发生了变化。WDS分析表明:随La0.67Mg0.33Ni3.0-xAlx合金中x的增加,Al在LaNi5相中的含量增加,但Al在LaNi2相的含量很少并且几乎不随x变化。电化学性能测试表明:Al替代Ni提高了La0.67Mg0.33Ni3.0合金电极的循环稳定性。但La0.67Mg0.33Ni3.0-xAlx合金电极的放电容量却随Al含量的增加而明显降低。
The phase structure and electrochemical properties of La0.67Mg0.33Ni3.0-xAlx (x = 0.0 ~ 0.35) alloys were investigated by X-ray diffraction, electron probe and electrochemical measurements. XRD results and EPMA observations show that La0.67Mg0.33Ni3.0 alloy consists of LaNi3 phase and La2Ni7 phase. However La0.67Mg0.33Ni3.0-xAlx (x = 0.1, 0.2, 0.35) alloy does not contain LaNi3 phase. The results show that the substitution of Al for Al changes the phase structure of La0.67Mg0.33Ni3.0 alloy, while the substitution of Al for Al is unfavorable for the formation of LaNi3 phase in La0.67Mg0.33Ni3.0 alloy. In addition, the phase structure of La0.67Mg0.33Ni3.0-xAlx (x = 0.1,0.2,0.35) alloy also changed with the increase of Al content. WDS analysis shows that the content of Al in LaNi5 phase increases with the increase of x in La0.67Mg0.33Ni3.0-xAlx alloy, but the content of Al in LaNi2 phase is small and almost does not change with x. Electrochemical tests show that the substitution of Al for Ni improves the cycle stability of La0.67Mg0.33Ni3.0 alloy electrode. However, the discharge capacity of La0.67Mg0.33Ni3.0-xAlx alloy electrode decreases with the increase of Al content.