Characteristics of AB₃-type co-free hydrogen storage alloy in low-temperature condition

In this paper, the characteristics of melted and annealed Co-free AB₃-type hydrogen storage alloys in low-temperature condition were investigated by electrochemical tests. A series of Co-free AB₃-type hydrogen storage alloys were synthesized with vacuum melting method, and be annealed by low-temperature heat treatment. The structures of alloys are simply discussed through SEM and XRD results. And discharge ability and cycle ability of alloys were tested. Experiment results indicate that characteristics of different AB₃-type hydrogen storage alloys are affected by low-temperature obviously, and heated treatment could increase the discharge capacity of hydrogen storage alloy effectively, and improve the charge-discharge stability of alloy. Furthermore, non-metal element substituted alloy shows better Low-temperature applicability due to its weak crystallization. The discharge capacity of La_0.7Mg_0.3Ni_2.9B_0.05 alloy remains 91.2% after 30 cycles at 273K. And discharge capacity of heated La_0.7Mg_0.3Ni_2.9(FeB)_0.1 alloy could reach to 250mA·g^-1.