Review of Hydrogen Storage Technologies and the Crucial Role of Environmentally Friendly Carriers

As the consumption rate of traditional fossil fuels continues to accelerate and environmental issues become increasingly severe, energy demand has become an urgent concern. In this context, hydrogen, as a clean and efficient energy source, has received widespread attention. However, because of its low density and gaseous nature, the storage of hydrogen faces challenging issues. Currently, storing hydrogen through compression and liquefaction methods is the most mature and widely adopted approach. However, the high pressure of gaseous storage and the issue of evaporation loss in liquid storage have driven the continuous development of solid-state storage. Among them, solid-state hydrogen storage methods, such as ammonia and metal hydrides, have received widespread attention. This is because these two storage methods do not involve carbon, which is more conducive to addressing environmental pollution issues. In this work, we review the gaseous, liquid, and solid-state storage methods of hydrogen; recapitulate hydrogen storage strategies; and investigate the latest developments in this field. Furthermore, we analyze the storage of carbon-free mediums, such as ammonia and certain metal alloy hydrides. These studies are expected to promote the healthy development of the hydrogen energy industry and make significant contributions to sustainable development.