Liquid Hydrogen (H2) typically has to be stored at -423°F (-253°C or 20 K). The temperature requirements for liquid hydrogen storage necessitate expending a great deal of energy to compress and chill the hydrogen into its liquid state. The cooling and compressing process requires energy, resulting in a net loss of about 30% of the energy that the liquid hydrogen is storing. The storage tanks are insulated to maintain temperature.
Liquid Hydrogen is often stored at higher pressure so significant reinforcement
The margin of safety concerning liquid hydrogen storage is a function of maintaining tank integrity and preserving the temperatures that liquid hydrogen requires. Combine the cost or energy required for the process to get hydrogen into its liquid state and the cost of tanks required to sustain the storage pressure and temperature, and liquid hydrogen storage becomes very expensive compared to other methods. Research in the field of liquid hydrogen storage centers around the development of composite tank materials, resulting in lighter, stronger tanks and improved methods for liquefying hydrogen.
Scientists had been producing hydrogen for years before it was recognized as an element. Written records indicate that Robert Boyle produced hydrogen gas as early as 1671 while experimenting with iron and acids. Henry Cavendish first recognized hydrogen as a distinct element in 1766.