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为改善无钴AB5储氢合金LaNi4.2Mn0.3Al0.3Cu0.15Fe0.05的循环性能,采用XRD、SEM等分析方法以及恒电流充放电等电化学测试技术,研究了系列La1-xPrxNi4.2Mn0.3Al0.3Cu0.15Fe0.05(x=0~0.3)合金的结构和电化学储氢性能。结果表明:制备的合金为单一的CaCu5结构,随着Pr替代La含量的增加,晶胞的a轴、c轴和晶胞体积均逐渐减小,c/a值逐渐增大。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高倍率放电性能得到明显改善。100个循环后的容量保持率S100分别为47.28%(x=0)、48.22%(x=0.1)、50.79%(x=0.2)和54.47%(x=0.3)。在放电电流为1800 mA/g的条件下,合金电极的高倍率性能45.13%(x=0)升高到56.19%(x=0.3)。合金电极的交换电流密度I0随Pr含量的增加而逐渐增大,而合金电极的氢扩散系数DH没有明显变化。
In order to improve the cycling performance of LaNi4.2Mn0.3Al0.3Cu0.15Fe0.05 alloy, a series of La1-xPrxNi4.2Mn0 alloys were investigated by XRD, SEM and electrochemical measurements such as constant current charge and discharge. Structure and Electrochemical Hydrogen Storage Properties of 3Al0.3Cu0.15Fe0.05 (x = 0 ~ 0.3) Alloy. The results show that the as-prepared alloy has a single CaCu5 structure. With the increase of Pr content, the a-axis, c-axis and unit cell volume of the unit cell gradually decrease and the c / a value increases gradually. The discharge capacity of the corresponding alloy is reduced, but the cycling stability and high rate discharge performance of the alloy electrode are obviously improved. The capacity retention S100 after 100 cycles was 47.28% (x = 0), 48.22% (x = 0.1), 50.79% (x = 0.2) and 54.47% (x = 0.3), respectively. With the discharge current of 1800 mA / g, the high-rate performance of the alloy electrode increased from 45.13% (x = 0) to 56.19% (x = 0.3). The exchange current density I0 of the alloy electrode gradually increases with the increase of Pr content, while the hydrogen diffusion coefficient DH of the alloy electrode does not change significantly.