(1. 兰州理工大学材料科学与工程学院，兰州 730050；
2. 兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室，兰州 730050)
摘 要: 采用真空电弧熔炼和热处理制备了A5B19型储氢合金La0.4Y0.6Ni3.52Mn0.18Al0.1，研究了退火温度(1173~1373 K)对合金La0.4Y0.6Ni3.52Mn0.18Al0.1相结构和电化学性能的影响规律。结果表明，随退火温度增加，主相A5B19型(3R-Ce5Co19+2H-Pr5Co19)相丰度逐渐增加至81%(质量分数)，其中1273 K时3R-Ce5Co19型相丰度最高(57%，质量分数)，进一步提高退火温度有利于合金形成2H-Pr5Co19型相。主相3R-Ce5Co19和2H-Pr5Co19型相的晶胞参数a、c及晶胞体积V随退火温度增加均呈逐渐增大趋势，但1373 K退火时其晶胞参数和体积均有所降低。电化学分析表明，随退火温度升高，合金电化学PCT曲线的放氢平台压有所增加；增加Ce5Co19型相丰度有利于改善合金电极的放电容量、倍率性能和循环稳定性；退火温度为1273 K时，合金的电化学性能最佳，其最大放电容量达到386.6 mA？h/g；放电电流密度为900 mA/g 时的高倍率性能ηHRD,900为76.7%，经循环100周后的容量保持率S100=90.1%。氢原子在合金体相中的扩散是影响合金电极高倍率放电性能和动力学反应的控制步骤。
关键字: 镍氢电池；La-Y-Ni系储氢合金；热处理；微观结构；电化学性能
（1. School of Materials Science and Engineering, Lanzhou University
of Technology, Lanzhou 730050, China;
2. State Key Laboratory of Advanced Processing and
Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou
730050, China）
Abstract:The effect of annealing temperature (1173-1373 K) on the phase structure and electrochemical performance of new A5B19 type hydrogen storage alloy La0.4Y0.6Ni3.52Mn0.18Al0.1 was systematically investigated. The results show that the content of the main phase A5B19 (3R-Ce5Co19+2H-Pr5Co19)-phase increases with the increase of annealing temperature, of which the 3R-Ce5Co19 phase abundance is the highest (57%, mass fraction) at 1273 K, and further increasing the annealing temperature will help the alloy form2H-Pr5Co19 type phase. The unit cell parameters a, c and unit cell volume V of the 3R-Ce5Co19 and 2H-Pr5Co19 type phases all gradually increase with the increase of annealing temperature, but the unit cell parameters and volume decrease after annealing at 1373 K. With the increase of annealing temperature, the desorption plateau of the electrochemical P-C isotherms increases. The electrochemical analysis show that increasing the abundance of Ce5Co19 type phase is beneficial to improve the discharge capacity, rate performance and cycle stability of the alloy electrodes. When the annealing temperature is 1273 K, the electrochemical properties of the alloy electrode are the best, the maximum discharge capacity reaches 386.6 mA？h/g (60 mA/g), the high-rate discharge ability at current density of 900 mA/g (HRD900) is 76.7%, and the capacity retention after 100 cycles (S100) is 90.1% (300 mA/g). The diffusion of hydrogen atoms in the alloy body is control step that affects the high-rate discharge performance and dynamic reaction of the alloy electrodes.
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