Solid-State Methods
Technologies that store hydrogen in a solid state are inherently safer and have the potential to be more efficient than gas or liquid storage. These are particularly important for vehicles with on-board storage of hydrogen. Technologies under investigation include:

Metal hydrides involve chemically reacting the hydrogen with a metal.

Carbon nanotubes take advantage of the gas-on-solids adsorption of hydrogen.

Glass microspheres rely on changes in glass permeability with temperature to fill the microspheres with hydrogen and trap it there.

Safety
Hydrogen has an excellent safety record, and is as safe for transport, storage and use as many other fuels. Nevertheless, safety remains a top priority in all aspects of hydrogen energy. The hydrogen community addresses safety through stringent design and testing of storage and transport concepts, and by developing codes and standards for all types of hydrogen-related equipment.