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为改善LaNi4.1Co0.6Mn0.3储氢合金的性能,研究了系列LaNi4.1-xCo0.6Mn0.3Alx(x=0,0.15,0.3,0.45)合金的结构和电化学储氢性能。结果表明:制备的合金为典型CaCu5型AB5储氢合金,随着Al替代量增加,LaNi5相的晶胞参数a、c、c/a值和晶胞体积逐渐增大,相应合金的放电容量有所降低,但合金电极的循环稳定性和不可逆自放电和高温容量得到明显改善。60个循环后的容量保持率(S60)分别为58.79%(x=0)、79.72%(x=0.3)、79.35%(x=0.45);合金电极不可逆容量损失率(贮存96h)由14.41%(x=0)降到2.38%(x=0.45)。在323K的放电容量由266.04mA.h/g(x=0)增加到302.4mA.h/g(x=0.15)、302.12mA.h/g(x=0.3)和299.88mA.h/g(x=0.45)。但Al替代Ni后,合金电极的交换电流密度I0和氢原子在合金内部的氢扩散系数DH降低,导致其高倍率放电性能变差。
In order to improve the performance of LaNi4.1Co0.6Mn0.3 hydrogen storage alloys, the structure and electrochemical hydrogen storage properties of LaNi4.1-xCo0.6Mn0.3Alx (x = 0,0.15,0.3,0.45) alloys were studied. The results show that the prepared alloy is a typical CaCu5 type AB5 hydrogen storage alloy. With the increase of Al substitution, the unit cell parameters a, c, c / a and the unit cell volume of LaNi5 phase increase gradually. The discharge capacity of the corresponding alloy is Decreased, but the alloy electrode cycle stability and irreversible self-discharge and high temperature capacity has been significantly improved. After 60 cycles, the capacity retention rate (S60) was 58.79% (x = 0), 79.72% (x = 0.3) and 79.35% (x = 0.45) respectively. The irreversible capacity loss (96h) (x = 0) to 2.38% (x = 0.45). The discharge capacity at 323K increased from 266.04 mA.h / g (x = 0) to 302.4 mA.h / g (x = 0.15), 302.12 mA.h / g (x = 0.3) and 299.88 mA.h / g x = 0.45). However, when Al is substituted for Ni, the exchange current density I0 of the alloy electrode and the hydrogen diffusion coefficient DH of the hydrogen atom in the alloy decrease, which leads to the deterioration of high-rate discharge performance.