Investigation on the structure and electrochemical properties of the laser sintered La0.7Mg0.3Ni3.5 hydrogen storage alloys

The structure and electrochemical properties of the La 0.7 Mg 0.3 Ni 3.5 alloys laser sintered at different powers were investigated. It is found that all alloys contain three phases La 3 MgNi 14 with the Ce 2 Ni 7 structure, LaNi 5 and LaMgNi 4 . The abundance of the main phase La 3 MgNi 14 is 43, 68 and 63 wt%, respectively, when sintering power varies from 1000 to 1200 and 1400 W. The laser sintered La 0.7 Mg 0.3 Ni 3.5 alloys can be activated to their maximum discharge capacity within three cycles. The discharge capacities of those alloys prepared by laser sintering at 1000, 1200 and 1400 W are 324.6, 352.8 and 340.5 mAh/g, respectively. The La 0.7 Mg 0.3 Ni 3.5 alloy laser sintered at 1200 W has a best cyclic stability ( S 100 = 58.4 % ) and high-rate dischargeability ( HRD 800 = 79.4 % ) due to the high amount of the main phase La 3 MgNi 14 .