A new AB4-type single-phase superlattice compound for electrochemical hydrogen storage

Abstract

Metal-hydride based hydrogen storage materials have recently been designed for rechargeable batteries where protons serve as charge carriers. However, the metal-hydride materials generally suffer from poor cycling stability during electrochemical hydrogen storage process. Herein, we report, for the first time, a new AB4-type single-phase La0.78Mg0.22Ni3.67Al0.10 metal-hydride superlattice compound with excellent electrochemical hydrogen storage properties. This metal-hydride compound is able to deliver a high discharge capacity of 393 mAh g−1, according to its hydrogen gas absorbability (1.50 wt%), and exhibit a superior rate capability of 180 mAh g−1 even at 1.8 A g−1. In addition, the compound retains its crystalline structure when subjects to electrochemical cycling and shows strong anti-oxidation ability in alkaline electrolyte, indicative of excellent cyclability. Our results demonstrate that the AB4-type superlattice structure metal-hydride can be a promising electrode material for hydrogen storage, and provide a new avenue for the applications of metal-hydride batteries.