Abstract:A2B7-type LaY2Ni10.2—xMnxAl0.3 (x=0.1,0.2,0.3,0.4,0.5) hydrogen storage alloys with different Mn contents were prepared by vacuum melting. The effect of partial replacement of Ni element by B-side Mn element on the structure and properties of the alloy was systematically studied by means of phase performance test, gaseous hydrogen storage performance test and electrochemical charge-discharge cycle performance test. The results show that the prepared alloy has polyphase structure, with Ce2Ni7 as the main phase, and there are a small amount of Gd2Co7, PuNi3 and LaNi5 phases. The abundance of main Ce2Ni7 phase increasse first and then drops with the increase of Mn content. When x is 0.3, the maximum hydrogen absorption of LaY2Ni9.9Mn0.3Al0.3 alloy is 1.131wt%. After 150 cycles of charge and discharge, LaY2Ni9.9Mn0.3Al0.3 alloy has the highest capacity retention rate of 58.0%.