Effect of B and Fe substitution on structure ofAB₃-type Co-free hydrogen storage alloy

来源期刊：中国有色金属学报(英文版)2010年第10期

论文作者：吴锋 张旻昱 穆道斌

文章页码：1885 - 1891

Key words：Ni-MH battery; AB₃-type; B substitution; Co-free hydrogen storage alloy

Abstract: A series of hydrogen storage Co-free AB₃-type alloys were directly synthesized with vacuum mid-frequency melting method, within which Ni of La_0.7Mg_0.3Ni₃ alloy was substituted by Fe, B and (FeB) alloy, respectively. Alloys were characterized by XRD, EDS and SEM to investigate the effects of B and Fe substitution for Ni on material structure. The content of LaMg₂Ni₉ phase within La_0.7Mg_0.3Ni₃ alloy reaches 37.9% and that of La_0.7Mg_0.3Ni_2.9(FeB)_0.1 alloys reduces to 23.58%. Among all samples, ground particles with different shapes correspond to different phases. The major substitution occurs in LaMg₂Ni₉ phase. Electrochemical tests indicate that substituted alloys have different electrochemical performance, which is affected by phase structures of alloy. The discharge capacity of La_0.7Mg_0.3Ni₃ alloy reaches 337.3 mA·h/g, but La_0.7Mg_0.3Ni_2.9(FeB)_0.1 alloy gets better high rate discharge (HRD) performance at the discharge rate of 500 mA/g with a high HRD value of 73.19%.