Nanostructured light metal hydride: Fabrication strategies and hydrogen storage performance

Abstract

Hydrogen can play an important role in the development of a sustainable energy system. However, storing hydrogen in a safe, efficient and economical manner remains a huge challenge. Light metal hydrides have attracted considerable attention for hydrogen storage owing to their high gravimetric and volumetric hydrogen densities. However, the strong covalent and/or ionic bonds between metal atoms and hydrogen result in slow kinetics, poor reversibility, and temperatures too high for dehydrogenation, hence delaying their practical large–scale applications. Considerable efforts have been toward tailoring the thermodynamic and kinetic properties of light metal hydride–based hydrogen storage materials for performance improvement, with the fabrication of nanoscale particles being a key and effective strategy. This review covers the preparation methods and hydrogen storage performance of nanostructured light metal hydrides. The physical and chemical properties and hydrogen storage behaviors of reversible light metal hydrides are first summarized, including MgH2, borohydrides, aluminum hydrides, amide–hydride systems, and hydride composites. The second section focuses on the research progress in nanostructuring for enhancing the reversible hydrogen storage properties of these hydrides. Finally, the main challenges and the future research prospects are discussed. The combination of nanostructuring and nanocatalysis can significantly enhance the performance of these hydrides and make them practical hydrogen carriers.