LaNi3.15-xMnxCo0.25 Al0.1储氢合金结构及电化学性能

摘要

为了研究 Mn 替代 Ni 对 AB3.5型储氢合金结构及电化学性能的影响,采用电弧炉熔炼制备 LaNi3.15-x MnxCo0.25 Al0.1合金。采用 XRD、SEM等材料分析方法以及恒电流充放电等电化学测试技术,研究 LaNi3.15-xMnxCo0.25 Al0.1(0≤x≤0.3)合金的结构和电化学储氢性能。结果表明：LaNi3.15-xMnxCo0.25 Al0.1(0≤x≤0.3)合金由多相组合形成,合金的主相为LaNi5和 La2 Ni7；随着 Mn替代 Ni含量的增加,LaNi5相中a轴和c 轴以及晶胞体积增加；合金电极的最大放电容量有所升高,由x=0的238 mA·h/g逐渐增加到x=0.3的277.1 mA·h/g；高倍率性能随着 Mn 含量的增加先升高后降低,在x=0.2时合金的高倍率性能最佳。%Mn was used for partial substitution Ni in order to improve the structure and electrochemical properties of the hy-drogen storage LaNi3.15-xMnxCo0.25Al0.1(0≤x≤0.3),LaNi3.15-xMnxCo0.25Al0.1(0≤x≤0.3)alloys were prepared by mag-netic levitation melting.A series of experiments were performed to study microstructure and electrode properties of La-Ni3.15-xMnxCo0.25 Al0.1 (0≤x≤0.3)alloys with X-ray diffraction (XRD)and scanning electron microscopy (SEM).The XRD spectroscopy shows that all the composites are mainly composed of La2 Ni7 phase and LaNi5 phase.The apparent in-crease of lattice parameters (a,c and V)has been observed with the increase of Mn content.With the increase of Mn con-tent,the maximum discharge capacity increases from 238 mA·h/g (x=0)to 277 mA·h/g(x=0.3).The discharge ca-pacity increases firstly and then decreases with the increase of Mn content.The performance of alloys is best when x=0.2.