Structural, electronic, and hydriding properties of Li2MgSi

An investigation of Li2MgSi, with particular emphasis on its potential as a hydrogen storage material, is reported. A cubic P4¯3m crystal structure, differing from previous determinations, is established. We find that the material reversibly sorbs ∼2.8 mass% hydrogen at T ∼ 300 °C according to the reaction Li2MgSi + H2 ↔ ½Mg2Si + 2LiH + ½Si. Electronic structure calculations indicate that Li2MgSi is a semiconductor with a small, indirect gap of ∼0.2 eV.