Abstract: The effect of La addition on the structure and electrochemical properties of amorphous LaMg11Zr+200Ni (LaMg11Zr : Ni = 1 : 2, m : m) hydrogen storage alloy prepared by mechanical alloying was investigated systematically. The results show that the alloys have an amorphous structure after 20 h ball-milling and the particles are significantly refined with the addition of La. The electrochemical tests indicate that the charging resistance of the alloy electrodes decreases with the addition of La. The maximum discharge capacity of the alloy electrodes increases with the increase of La addition, while the cyclic stability and high-rate discharge performance increase firstly and then decrease as the La content increases. When the mass fraction of La is up to 5%, the maximum discharge capacity after charging/discharging of 30 cycles of the alloy electrode is increased from 576.2 to 597.5mA · h/g, and the capacity retention rate and high-rate dischargeability (HRD) of the alloy electrode are increased by 20.5% and 29.4% respectively compared with those of the alloy electrode without the La addition, exhibiting the best comprehensive electrochemical performances.

Key words: hydrogen storage alloy| La addition| phase structure| electrochemical characteristics

摘要： The effect of La addition on the structure and electrochemical properties of amorphous LaMg11Zr+200Ni (LaMg11Zr : Ni = 1 : 2, m : m) hydrogen storage alloy prepared by mechanical alloying was investigated systematically. The results show that the alloys have an amorphous structure after 20 h ball-milling and the particles are significantly refined with the addition of La. The electrochemical tests indicate that the charging resistance of the alloy electrodes decreases with the addition of La. The maximum discharge capacity of the alloy electrodes increases with the increase of La addition, while the cyclic stability and high-rate discharge performance increase firstly and then decrease as the La content increases. When the mass fraction of La is up to 5%, the maximum discharge capacity after charging/discharging of 30 cycles of the alloy electrode is increased from 576.2 to 597.5mA · h/g, and the capacity retention rate and high-rate dischargeability (HRD) of the alloy electrode are increased by 20.5% and 29.4% respectively compared with those of the alloy electrode without the La addition, exhibiting the best comprehensive electrochemical performances.

关键词: hydrogen storage alloy| La addition| phase structure| electrochemical characteristics