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在氩气保护条件下用高频感应悬浮熔炼法制备La0.7(Pr0.75Nd0.25)xMg0.3Ni3.3(Co0.7Al0.3)0.3(x=0.0,0.1,0.2,0.3)合金,研究混合稀土含量对合金储氢和电化学性能的影响。合金XRD相分析结果表明,合金相主要由LaNi5,(La,Pr)Mg2Ni9,(La,Nd)2Ni7和LaNi3相组成。随着Pr和Nd含量的增加,合金吸氢量先增加后减小,最大吸氢量为1.42%(质量分数)(x=0.2),放氢平台变短坪斜增加。合金电极电化学测试表明,电极最大放电容量为378 mAh·g-1(x=0.2),放电容量保持率S100从53.2%(x=0.0)增加到56.2%(x=0.3),增加Pr和Nd的含量可以提高电极的循环稳定性。合金电极电化学阻抗谱、线性极化、Tafel极化和循环伏安特性研究表明,添加适量的Pr和Nd可以提高电极动力学性能。当x=0.1时,合金电极电荷传递电阻Rct和极化电阻Rp较小,交换电流密度I0、极限电流密度IL以及阳极峰电流密度Ip较大,合金电极动力学性能较好。
La0.7 (Pr0.75Nd0.25) xMg0.3Ni3.3 (Co0.7Al0.3) 0.3 (x = 0.0,0.1,0.2,0.3) alloy was prepared by high-frequency induction suspension melting under argon atmosphere, The effect of mixed rare earth content on hydrogen storage and electrochemical performance of the alloy was investigated. The results of XRD analysis show that the alloy phase mainly consists of LaNi5, (La, Pr) Mg2Ni9, (La, Nd) 2Ni7 and LaNi3 phases. With the increase of Pr and Nd content, the amount of hydrogen absorption first increased and then decreased, the maximum hydrogen absorption was 1.42% (x = 0.2), and the hydrogen reduction platform became shorter and the slope increased. Electrochemical tests showed that the maximum discharge capacity of the electrode was 378 mAh · g-1 (x = 0.2) and the discharge capacity retention S100 increased from 53.2% (x = 0.0) to 56.2% (x = 0.3) The content of Nd can improve the cycle stability of the electrode. Electrochemical impedance spectroscopy, linear polarization, Tafel polarization and cyclic voltammetry of the alloy electrodes show that adding appropriate amounts of Pr and Nd can improve the electrode kinetics. When x = 0.1, the electrode charge transfer resistance Rct and the polarization resistance Rp of the alloy electrode are smaller, the exchange current density I0, the limiting current density IL and the anode peak current density Ip are larger, and the alloy electrode has better dynamic performance.