Hydrides Hold Hydrogen on hands Metal hydride systems store hydrogen in the interatom spaces of a granular metal. Various metals can be used. The hydrogen is released by heating. These systems are reliable and compact, but they can be heavy and expensive.
Slush If liquid hydrogen is suddenly subjected to a vacuum it will evaporate with a subsequent cooling of the liquid mass to cause the temperature to fall below the freezing point of -259.2 C and solid hydrogen will be produced. This mixture of liquid and solid hydrogen is called "slush" and provides more dense storage of hydrogen than liquid hydrogen.
Liquid Cooling hydrogen to below the boiling point of - 252.7 C allows storage as a cryogenic liquid without the need for pressurization. Cryogenic storage of hydrogen allows regular commercial shipment by truck and rail. Many commercial processes such as glass manufacturing, brazing, heat treating, food hydrogenation, and semiconductor manufacturing are served by deliveries of liquid hydrogen. Liquid hydrogen has facilitated the U.S. space exploration program.
Pressure Ergenics ST-Series hydrogen storage unit Stainless steel and Aluminium Long Life (100,000 times)