Solid-state hydrogen storage in metal hydrides: mechanistic insights into kinetics, activation, and destabilization...

In a hydrogen-based economy, safe and efficient hydrogen storage is a technological challenge for widespread hydrogen use. The liquid and compressed gas hydrogen storage techniques have some limitations that don't meet future demands. Solid-state materials are promising alternatives that can store hydrogen through physical or chemical binding at the material's surface, and they offer many advantages over conventional hydrogen storage systems. For the enhancement of hydrogenation characteristics of metal hydride systems, much research has been done. The recent advancements and various aspects of metal hydrides, including their characteristics and performance relevant to storage applications, are explored in this review article. Specifically, it examines a material's response to variation in temperature and pressure, and also provides understanding of reaction kinetics, cyclic stability, potential toxicity and hydrogen storage capacity. Specific emphasis is placed on the thermodynamic destabilization strategies that have been effective in achieving a rise in desorption plateau pressures, to enable hydrogen release at ambient temperature. In addition, the detailed mechanisms for how surface fluorination and catalysts are able to lower high activation energy barriers to rapidly facilitate absorption/desorption kinetics are carefully examined. The review also focuses on key engineering challenges such as degradation of structure and lattice strain arising from long-term cycling stability. The principle of H₂ storage in metal hydride-based solid state systems and their applications in H₂ technologies and advancing energy are also discussed herein.