Effective attempt towards enhancing hydrogen storage performance of LPSO phase contained high-capacity Mg-based alloy by Indium

Abstract

To explore more possibilities for hydrogen economy, Mg-based alloys containing long period stacking ordered (LPSO) phase for solid-state hydrogen storage deserve attention. In this paper, indium (In) element is adopted to alter the de/hydrogenation abilities of Mg–Y–Zn alloys. The relationship between microstructural features and hydrogen storage behaviors of Mg95Y3Zn2-xInx (x = 0, 1 and 2 at.%) alloys are discussed in detail. Indium element can modify the morphology of LPSO phase and more Mg interfaces are obtained. LPSO phase cannot be generated when Zn is completely replaced by In element; instead α-Mg grains and eutectic phase (Mg + MgYIn) the constitute the In2 alloy. Element In benefits the activation process of the alloys in this paper, which helps the alloy particles to be hydrogenated quickly in the first hydrogenation. Specifically, 1 at.% In substitution for Zn accelerates dehydrogenation and the dehydrogenation temperature reduces by 11 °C. The benefits of In element for dehydrogenation behaviors mainly come from increased Mg grain boundaries, larger MgH2 lattice constants with weaker Mg–H bonds, uniformly distributed nanoscale YH2/YH3 phase.