Microstructure and hydrogen storage properties of Mg(In) solid solution

Mg(In) solid solutions with different compositions were prepared by sintering and ball milling method. X-ray diffraction was used to analyze the phases and phase transition of the alloys during the hydriding and dehydriding process. Lattice constants of Mg(In) solid solution were accurately calculated by Rietveld method. Morphology and phase distribution of the samples were observed by SEM. The hydrogen absorption and desorption performances of the alloys were measured by Sievert method, and dehydriding temperatures were determined by DSC tests. The results show that the lattice constants of Mg are reduced by dissolving of In, and that Mg(In) solid solutions were hydrogenated to MgH2 and intermetallic compounds MgxIny, which reversibly return to Mg(In) solid solution after dehydrogenation. The reversible hydriding and dehydriding phase transitions of Mg(In) solid solutions and interfacial alloying effectively reduce the dehydriding enthalpy, thus lowering the dehydriding temperature and improving the hydriding and dehydriding kinetics of the Mg(In) solid solutions. The plateau pressure of Mg(In) solid solutions is improved and the hydriding and dehydriding lag is reduced compared with those of pure Mg.