Challenges associated with hydrogen storage systems due to the hydrogen embrittlement of high strength steels

Hydrogen is a promising alternative to fossil fuels and is extensively used in process industries. The transportation industry is gearing up towards the use of fuel cells where hydrogen, as a fuel, plays a major role. Irrespective of the application/sector, safe handling and storage of hydrogen are crucial. Storing hydrogen in metal cylinders as compressed gas is a common practice. However, hydrogen embrittlement is a challenge in such cases and needs to be addressed. Embrittlement leads to the deterioration of the metal cylinders in which the hydrogen gas is stored and is therefore a safety concern. High-strength steels are more susceptible to hydrogen embrittlement as susceptibility to the phenomenon increases with strength. Safe hydrogen storage systems demand improved storage materials and modification of existing ones. Few materials and methods are available to reduce hydrogen diffusion in these steels. However, a detailed microstructural analysis of high-strength steel is necessary to make it a hydrogen-impermeable material. Multilayered coatings can be effective in the prevention of embrittlement. In this article, the analysis of current hydrogen storage methods along with the various coatings and deposition techniques that can reduce hydrogen permeation in high-strength steels is carried out.