La0.7-xPrxZr0.1 Mg0.2 Ni2.75 Co0.45 Fe0.1 Al0.2(x=0.00,0.05,0.10,0.15,0.20)合金储氢及电化学性能研究

摘要

The La0.7-xPrxZr0.1 Mg0.2 Ni2.75 Co0.45 Fe0.1 Al0.2 (x=0.00,0.05,0.10,0.15,0.20)composites were prepared by the magnetic induction melting method under the argon atmosphere protection.The effects of partial sub-stitution of Pr for La on the electrochemical characteristics of the alloys were investigated systematically.The results showed that the alloy composition was mainly composed of LaNi5 phase and La2 Ni7 phase,and the cell volumes of them decreased as Pr added.The decrease of the cell volumes was unfavourable for the hydrogen atom diffusion in the alloy electrodes bulks,which resulted in poor dynamics performance.However,the cycle stability of the La0.7-x-PrxZr0.1 Mg0.2 Ni2.75 Co0.45 Fe0.1 Al0.2 (x=0.00,0.05,0.10,0.15,0.20)alloy electrodes improved due to the good anti-corrosion performance of the Pr element,and the capacity retention of the them increased gradually from 66.2%(x=0.00)to 69.5%(x=0.05),73.2%(x=0.10),74.0%(x=0.15)and 75.1%(x=0.20),respectively.%在Ar气保护下,采用高频感应悬浮炉制备La0.7-xPrxZr0.1 Mg0.2 Ni2.75 Co0.45 Fe0.1 Al0.2(x=0.00,0.05,0.10,0.15,0.20)合金,研究Pr替代La对合金电极电化学性能的影响.结果显示,所有合金主要由LaNi5和La2 Ni7相组成,以Pr替代La后,LaNi5相和La2 Ni7合金相的晶胞收缩,导致氢原子在合金电极体内扩散受限,合金电极的动力学性能下降.但由于Pr的抗腐蚀作用,合金电极循环稳定性增加,经过200次充放电循环后容量保持率分别从66.2%(x=0.00)逐渐增加到69.5%(x=0.05)、73.2%(x=0.10)、74.0%(x=0.15)和75.1%(x=0.20).