MgCNi3 prepared by powder metallurgy for improved hydrogen storage properties of MgH2

Abstract With the depletion of global energies resources, improvement of hydrogen storage properties of materials like MgH 2 is of great interest for future efficient renewable resources. In this study, a novel antiperovskite MgCNi 3 was synthesized by powder metallurgy then introduced into Mg to fabricate Mg MgCNi 3 composite. The hydrogen storage properties of the obtained Mg MgCNi 3 composite were evaluated. Mg MgCNi 3 showed a high capacity of hydrogen storage and fast kinetics of hydrogen uptake/release at relatively low temperatures. About 4.42 wt% H 2 was absorbed within 20 min at 423 K, and 4.81 wt% H 2 was reversibly released within 20 min at 593 K. By comparison, milled MgH 2 absorbed only 0.99 wt% H 2 and hardly underwent any hydrogen evolution under the same conditions. In addition, Mg MgCNi 3 composite showed outstanding cycling stability, with hydrogen absorption capacity retention rates reaching 98% after ten cycles at 623 K. The characterization analyses revealed that MgCNi 3 and Mg formed Mg 2 NiH 4 hydride and carbonaceous material during hydrogenation, where Mg 2 NiH 4 induced dehydrogenation of MgH 2 and carbon played a dispersive role during the composite reaction. Both features synergistically benefited the hydrogen storage properties of MgH 2 .