AlH3 as a hydrogen storage material: recent advances, prospects and challenges

Aluminum hydride (AlH3) is a covalently bonded trihydride with a high gravimetric (10.1 wt%) and volumetric (148 kg.m(-3)) hydrogen capacity. AlH3 decomposes to Alland H-2 rapidly at relatively low temperatures, indicating good hydrogen desorption kinetics at ambient temperature. Therefore, AlH3 is one of the most prospective candidates for high-capacity hydrogen storage materials. Firstly, this review briefly summarizes the basic chemical and physical characteristics of AlH3. Then, its synthesis, dehydrogenation thermodynamics and kinetics, regeneration and methods for improving reversibility of hydriding are described with the aim of applying this material for hydrogen storage. In accordance with the fact that AlH3 is generally formed by reacting Al with H2 at extremely high hydrogen pressure, the high-pressure study of this hydride is discussed in detail. Finally, the advantages, weaknesses, critical technical challenges and outlook of this field are discussed.