Research progress in solid-state hydrogen storage alloys: A review

Promoting the widespread utilization of hydrogen energy, supported by efficient storage and conversion technologies, represents a pivotal strategy for addressing global energy and environmental challenges. Among these technologies, the development of compact, safe, and economically viable hydrogen storage (abbreviated as H-storage) solutions is essential for advancing a hydrogen-based economy. Conventional technologies, such as compressed gaseous hydrogen and cryogenic liquid hydrogen, face limitations including safety concerns, high energy consumption, and significant evaporation losses. In comparison, metal hydride-based storage offers a promising alternative by enabling hydrogen to form stable compounds with metals under moderate conditions, thereby improving safety and hydrogen density (H-density). The review provides a comprehensive analysis of recent advances in the most appealing solid-state hydrogen storage alloys (HSAs), with a focus on their de-/hydrogenation properties and cycling stability. Key materials discussed include V-based body-centered cubic (BCC) HSAs, Mg-based crystalline and amorphous HSAs, and multi-component alloys—either employed as used as standalone H-storage materials or as multifunctional catalysts to improve hydrogen kinetics of Mg-based materials. The review begins by examining synthesis methods for HSAs. Afterwards, the review summarizes and discusses the H-storage properties of the above HSAs, with a particular emphasis on their de-/hydriding kinetics, thermodynamics, and cycling performance. In addition to highlighting the latest advancements of solid-state HSAs in the field of hydrogen energy, the remaining challenges and prospects of the emerging research are also discussed.