Reversible hydrogen storage and phase transformation with altered desorption pressure in Mg90In5Cd5 ternary alloy

• The ternary solid solution alloy Mg90In5Cd5 was synthesized by sintering and ball-milling.
• The Mg90In5Cd5 solid solution alloy showed reversible hydrogenation–dehydrogenation performances.
• The Mg90In5Cd5 alloy revealed enhanced hydrogenation kinetics and elevated equilibrium pressure for the MgH2.

The ternary solid solution alloy Mg90In5Cd5 was prepared by sintering the elemental powder mixture and subsequent mechanical milling. It was found that the hydrogenated products of Mg90In5Cd5 alloy consisted of MgH2, MgIn and Mg3Cd, which could fully recover to Mg(In, Cd) ternary solid solution after dehydrogenation. The PCI results showed reversible hydrogen storage capacity of ca. 4.3 wt.% and elevated equilibrium pressure for the MgH2 in the hydrogenated Mg90In5Cd5 alloy compared with pure MgH2. The Mg90In5Cd5 alloy also exhibited enhanced hydrogenation kinetics with decreased hydrogenation activation energy of 61.0 kJ/mol, but the dehydrogenation rate is slow due to the long-range diffusion of In and Cd in MgH2.