Visions for hydrogen-based materials for energy applications

The world’s dependence on fossil fuels necessitates rapid advancement of clean storage and renewable energy technologies. There is abundance of renewable energy in the form of solar irradiance and wind, and the most commonly used energy carrier for these sources is electricity using batteries. Hydrogen is a viable energy carrier because of its diverse chemistry and capacity to form a wide range of bonds and interactions with most other elements. Hydrogen-based materials encompass a great variety of compositions, structures and properties, which modern synthesis methods can further tailor towards targeted applications. Of these, sodium tetrahydridoborate (NaBH 4 ) is a candidate for long-distance transport and seasonal hydrogen storage, releasing up to 137 kg H 2 /m 3 upon reaction with water. Metallic hydrides can be used for hydrogen storage (limited to gravimetric densities of approximately 2 wt% H 2 ), used in nickel-metal hydride batteries and are also applicable to piston-free hydrogen compression to 100 MPa and higher. Reactive hydride composites may provide enhanced storage capacities suitable for mobile applications, while physisorption in inexpensive porous materials enables hydrogen storage at cryogenic temperatures. Beyond hydrogen storage, boron-based hydrides have attracted recent interest owing to very high cationic conductivity at moderate temperatures. Divalent cationic conductors, such as Mg 2+ and Ca 2+ , show particular promise as electrolytes in novel solid-state batteries. In addition, new types of hydrides with unexpectedly high hydrogen content, denoted ‘super-hydrides’, have been identified as high-temperature superconductors. Collectively, hydrogen-containing materials offer the potential of new applications across areas of energy storage and transport, conversion, and superconductivity, underscoring the role of hydrogen not merely as an energy carrier but as a foundation for the next generation of viable, decarbonised energy infrastructure. Continued research may accelerate the global transition towards clean and renewable energy systems.