Review of Hydrogen Storage in Solid-State Materials

As a kind of clean energy, hydrogen energy has great potential to reduce environmental pollution and provide efficient energy conversion, and the key to its efficient utilization is to develop safe, economical and portable hydrogen storage technology. At present, hydrogen storage technology lags behind hydrogen production and use, which is the bottleneck restricting the development of hydrogen energy. In this paper, several current solid-state hydrogen storage methods are reviewed, including hydrate hydrogen storage, alloy hydrogen storage and MOF hydrogen storage. At the hydrogen storage density level, the hydrogen storage capacity of 1K-MOF-5 can reach 4.23 wt% at 77 K and 10 MPa, and remains basically unchanged in 20 isothermal adsorption and desorption experiments. At the level of temperature and pressure of hydrogen storage, the alloy can realize hydrogen storage under ambient conditions. At the economic level, the cost of hydrogen storage in hydrates is only USD 5–8 per kilogram, with almost zero carbon emissions. Through the analysis, it can be seen that the above solid-state hydrogen storage technologies have their own advantages. Although hydrate hydrogen storage is lower than alloy materials and MOF materials in hydrogen storage density, it still has huge potential for utilization space because of its low cost and simple preparation methods. This paper further provides a comprehensive review of the existing challenges in hydrate research and outlines prospective directions for the advancement of hydrogen storage technologies.