CAJ | 학술논문

采用X射线衍射、电子探针和电化学测试研究了La2Mg1-xAlxNi7.5Co1.5(x=0.0,0.1,0.3,0.5)合金的相结构和电化学性能.XRD结果和EPMA观察表明,少量的Al替代Mg(x=0.1)不改变La2MgNi7.5Co1.5合金的相组成,合金仍然由LaNi3相和αLa2Ni7相组成,然而La2Mg0.9Al0.1Ni7.5Co1.5合金中LaNi3相的丰度明显下降,αLa2Ni7相的丰度则增加,较多的Al替代Mg改变了La2MgNi7.5Co1.5合金的相组成并导致合金中LaNi3相消失,La2Mg1-xAlxNi7.5Co1.5合金中Al含量的变化对合金中不同相晶胞参数的影响不相同.此外,少量的Al替代Mg(x=0.1)几乎不降低La2MgNi7.5Co1.5合金的贮氢容量和最大电化学放电容量,但随La2Mg1-xAlxNi7.5Co1.5合金中Al含量的增加,合金的贮氢容量、最大电化学放电容量和活化性能不断下降,Al替代Mg能明显提高La2MgNi7.5Co1.5合金的电化学循环稳定性,对提高该合金电极的高倍率放电性能也是有利的.
채용X사선연사、전자탐침화전화학측시연구료La2Mg1-xAlxNi7.5Co1.5(x=0.0,0.1,0.3,0.5)합금적상결구화전화학성능.XRD결과화EPMA관찰표명,소량적Al체대Mg(x=0.1)불개변La2MgNi7.5Co1.5합금적상조성,합금잉연유LaNi3상화αLa2Ni7상조성,연이La2Mg0.9Al0.1Ni7.5Co1.5합금중LaNi3상적봉도명현하강,αLa2Ni7상적봉도칙증가,교다적Al체대Mg개변료La2MgNi7.5Co1.5합금적상조성병도치합금중LaNi3상소실,La2Mg1-xAlxNi7.5Co1.5합금중Al함량적변화대합금중불동상정포삼수적영향불상동.차외,소량적Al체대Mg(x=0.1)궤호불강저La2MgNi7.5Co1.5합금적저경용량화최대전화학방전용량,단수La2Mg1-xAlxNi7.5Co1.5합금중Al함량적증가,합금적저경용량、최대전화학방전용량화활화성능불단하강,Al체대Mg능명현제고La2MgNi7.5Co1.5합금적전화학순배은정성,대제고해합금전겁적고배솔방전성능야시유리적.
The phase structure and electrochemical properties of La2Mg1-xAlxNi7.5Co1.5 (x=0.0,0.1,0.3,0.5) 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 small quantity replacement Mg by Al (x=0.1) does not change phase composition of La2MgNi7.5Co1.5 alloy, the alloy is still constituted with LaNi3 phase and αLa2Ni7 phase, but the abundance of LaNi3 phase decreases obviously and that of αLa2Ni7 increases in the La2Mg0.9Al0.1Ni7.5Co1.5 alloy. The more Al substitution will change phase composition of the alloy, resulting in LaNi3 phase disappearance. Influence of change of Al content on cell parameters of different phases of the La2Mg1-xAlxNi7.5Co1.5 alloy is different. Moreover, little replacement of Mg by Al (x=0.1)lowers scarcely hydrogen storage capacity and maximum electrochemical discharge capacity of the alloy, but with the increment of Al content in the La2Mg1-xMgxNi7.5Co1.5 alloy, hydrogen storage capacity, activation property and maximum electrochemical discharge capacity of the alloys decrease continuously. Al substitution for Mg can improve obviously electrochemical cyclic stability of La2MgNi7.5Co1.5 alloy electrode, and is beneficial to improve high rate dischargeability of the alloy electrode.