Hydrogen absorption-desorption cycle durability of SmMgNi4

The reversible hydrogen storage capacity and structural features against cycle numbers of SmMgNi4 compound prepared by the combination of ball-milling with sintering are investigated systematically in this work. It is found that the structure of SmMgNi4 with an exchange between Sm and Mg by 13% has a good stability without occurrence of hydrogen-induced amorphization and phase decomposition upon multiple cycling. However, about 16% capacity loss is still observed at the early stages of hydrogen ab-/desorption cycles at 298 K. The increase in lattice strain caused by the accumulation of dislocations is believed to be responsible for the capacity degradation of SmMgNi4.