Recent Advances in Solid-State Hydrogen Storage Based on Metal Hydrides and Nanoporous Carbon Materials

Hydrogen is considered one of the most promising energy carriers for sustainable and carbon-neutral energy systems. However, the large-scale deployment of hydrogen technologies is limited by the lack of efficient, safe, and cost-effective hydrogen storage methods. This review examines current hydrogen storage technologies and the physical and chemical mechanisms underlying hydrogen adsorption. Traditional storage approaches, including compressed gas and liquid hydrogen, are briefly analyzed with respect to their advantages, limitations, safety concerns, and energy requirements. Special focus is given to solid-state hydrogen storage systems based on metal hydrides, which offer high storage capacities and enhanced operational safety. Recent advances in intermetallic hydrides, magnesium-based materials and complex hydrides are discussed, along with challenges related to thermodynamic stability, sorption kinetics, thermal management, and cycling durability. This review also highlights recent developments in nanoporous carbon materials and the role of the hydrogen spillover mechanism in improving adsorption performance. Experimental studies reporting hydrogen adsorption capacities above 7 wt.% and up to 11.2 wt.% are analyzed. Based on the reviewed literature, key research directions are identified for optimizing the adsorption properties of advanced materials and accelerating the development of efficient and sustainable hydrogen storage technologies for future energy applications.