Chemical-based Hydrogen Storage Systems: Recent Developments, Challenges, and Prospectives

Hydrogen (H₂) is being acknowledged as the future energy carrier due to its high energy density and potential to mitigate the intermittency of other renewable energy sources. H₂ also ensures a clean, carbon-neutral, and sustainable environment for current and forthcoming generations by contributing to the global missions of decarbonization in the transportation, industrial, and building sectors. Several H₂ storage technologies are available and have been employed for its secure and economical transport. The existing H₂ storage and transportation technologies like liquid-state, cryogenic, or compressed hydrogen are in use but still suffer from significant challenges regarding successful realization at the commercial level. These factors affect the overall operational cost of technology. Therefore, H₂ storage demands novel technologies that are safe for mobility, transportation, long-term storage, and yet it is cost-effective. This review article presents potential opportunities for H₂ storage technologies, such as physical and chemical storage. The prime characteristics and requirements of H₂ storage are briefly explained. A detailed discussion of chemical-based hydrogen storage systems such as metal hydrides, chemical hydrides (CH₃OH, NH₃, and HCOOH), and liquid organic hydrogen carriers (LOHCs) is presented. Furthermore, the recent developments and challenges regarding hydrogen storage, their real-world applications, and prospects have also been debated.