Progress and perspectives on hydrogen storage and release in negative hydrogen medium †

Hydrogen energy has attracted much attention as a clean energy source, but its large-scale application faces storage and transportation challenges. Negative hydrogen medium (metal hydrides, borohydrides) materials have become a research hotspot due to their efficient hydrogen storage capacity. Investigating the role of negative hydrogen in the structure of materials can improve our understanding of the various structural properties of hydrogen and provide valuable insights into the design of hydrogen-containing materials with new functionalities. This paper reviews the research progress of negative hydrogen medium in recent years. Specifically, they include the magnesium hydride (MgH2), sodium aluminum hydride (NaAlH4), lithium borohydride (LiBH4), ammonia borane (AB, NH3BH3), sodium borohydride (NaBH4), potassium borohydride (KBH4), and so on. The catalytic performance of different catalysts used for hydrogen storage and release in negative hydrogen medium in the last three years is summarized, and the structure-performance relationship of different catalysts for negative hydrogen medium is also described on the nanoscale and atomic scale, respectively. The reasons for the monolithic catalysts and light-enhanced hydrogen release performance are also described. The research progress on the cycle regeneration of negative hydrogen materials is summarized from both computational and experimental perspectives. Finally, the main challenges and development prospects of negative hydrogen medium in the future are put forward. This review contributes to a basic understanding of the design and mechanistic studies of negative hydrogen medium catalysts and provides effective design principles for overcoming the problems of low rates of hydrogen storage and release and the difficulty of cyclic regeneration.