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研究了Nd元素部分取代对La0.8-xNdxMg0.2Ni3.3Co0.5(x=0～0.15)合金的相结构和电化学性能影响。研究发现,由X射线衍射图谱分析,合金主要由CaCu5型相、PuNi3型相及少量Pr5Co19型相组成,随着Nd含量的增加,合金物相晶胞参数和晶胞体积在逐渐降低。合金电极电化学测试显示,随着Nd含量的增加,La0.8-xNdxMg0.2Ni3.3Co0.5(x=0～0.15)合金电极电化学容量从370.5 mAh.g-1(x=0)增加到最大容量377.7 mAh.g-1(x=0.05),然后下降369.2 mAh.g-1(x=0.15);合金电极电化学容量经过100次循环的容量保持率S100从65.9%(x=0)增加到最大至72.8%(x=0.15);合金电极的高倍率性能HRD1200逐渐从83%(x=0)增加到88%(x=0.15),动力学测试分析结果显示合金高倍率性能是由电催化活性和氢在合金体内的扩散两个过程控制共同控制的。综合考虑,Nd取代量为0.15时,合金电极电化学性能较好。
The effect of partial substitution of Nd on the phase structure and electrochemical performance of La0.8-xNdxMg0.2Ni3.3Co0.5 (x = 0 ~ 0.15) alloys was investigated. The results show that the alloy is mainly composed of CaCu5 phase, PuNi3 phase and a small amount of Pr5Co19 phase by X-ray diffraction analysis. With the increase of Nd content, the lattice parameters and the unit cell volume of the alloy phase decrease gradually. Electrochemical tests showed that with the increase of Nd content, the electrochemical capacity of La0.8-xNdxMg0.2Ni3.3Co0.5 (x = 0 ~ 0.15) electrode increased from 370.5 mAh.g-1 (x = 0) (X = 0.15); the capacity retention of the electrochemical capacity of the alloy electrode after 100 cycles S100 decreased from 65.9% (x = 0) to the maximum capacity of 377.7 mAh.g-1 (x = 0.05) and then decreased by 369.2 mAh.g- ) Increased to 72.8% (x = 0.15). The HRD 1200 of the alloy electrode gradually increased from 83% (x = 0) to 88% (x = 0.15). The kinetic test results showed that the high rate capability of the alloy was By the electrocatalytic activity and diffusion of hydrogen in the alloy body two process control jointly controlled. Taken together, Nd substitution of 0.15, the electrochemical properties of the alloy electrode is better.