Review of hydrogen storage techniques for on board vehicle applications

Hydrogen gas is increasingly studied as a potential replacement for fossil fuels because fossil fuel supplies are depleting rapidly and the devastating environmental impacts of their use can no longer be ignored. H2 is a promising replacement energy storage molecule because it has the highest energy density of all common fuels by weight. One area in which replacing fossil fuels will have a large impact is in automobiles, which currently operate almost exclusively on gasoline. Due to the size and weight constraints in vehicles, on board hydrogen must be stored in a small, lightweight system. This is particularly challenging for hydrogen because it has the lowest energy density of common fuels by volume. Therefore, a lot of research is invested in finding a compact, safe, reliable, inexpensive and energy efficient method of H2 storage. Mechanical compression as well as storage in chemical hydrides and absorption to carbon substrates has been investigated. An overview of all systems including the current research and potential benefits and issue are provided in the present paper.