【摘要】 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。更多还原

【Abstract】 The structure and electrochemical properties of La0.8-xNdxMg0.2Ni3.3Co0.5(x =0 ～0.15) alloys after partial substitution of Nd for La were investigated.The XRD analysis of alloys showed that the alloys were constituted of CaCu5-type phase,PuNi3-type phase and minority Pr5Co19-type phase,with increasing the content of neodymium,the lattice parameters and the cell volume decreased.Electrochemical measurements showed that with the increase of Nd content,the maximum discharge capacity of the alloy electrodes first increased from 370.5 mAh.g-1(x = 0) to 377.7 mAh.g-1(x = 0.15) and then decreased to 369.2 mAh.g-1(x = 0.15);the cycling stability was determined by discharge capacity retention rate(S100) after 100 charge/discharge cycles.The cycling stability(S100) in-creased from 65.9%(x = 0) to 72.8%(x = 0.15) gradually;when the discharge current density was 1200 mA.g-1,the high rate dischargeability(HRD1200) increased from 83%(x = 0) to 88%(x = 0.15),the high rate dischargeability was controlled by both the charge-transfer on the alloy surface and the hydrogen diffusion.Considering the comprehensive electrochemical properties,the alloy electrode with Nd content of 0.15 had a better performance.更多还原