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 Al and H2 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. 铝氢化物(AlH3)是一种三共价键的氢化物, 具有较高的质量(10.1 wt%)和体积(148 kg H2•m-3)储氢容量。在相对温和的温度下, AlH3可快速分解为铝和氢气, 具有良好的放氢动力学。因此, AlH3是最有前景的高容量储氢材料之一。本文首先简要概述了AlH3的基本化学和物理特性。然后介绍了该材料的合成、脱氢热力学和动力学、再生循环以及提高吸放氢可逆性的方法。因为由Al与H2反应生成AlH3需要极高的氢气压力, 本文详细讨论了AlH3的高压研究。最后, 讨论了AlH3研究领域中的优势、劣势、关键技术挑战和发展前景。