Researchers have been working long and hard on the question of how to store hydrogen in cars for maximum safety and range of the vehicles. Compressing hydrogen gas at 5,000 to 10,000 psi represents not only safety issues, but challenges in regard to what kinds of materials to use, the shapes of the canisters, detection of leaks and other issues.
So, a recent trend has been increased research on using metal hydride containers to store hydrogen gas. With metal hydrides, hydrogen gas only has to be compressed to a couple hundred pounds per square inch (if at all). The hydrogen bonds to the metal and are released by the ambient heat of the vehicle.
But, the major problem with metal hydride storage is that metal is heavy and adds considerable weight to the vehicles. So, a few researchers have been testing other materials as an alternative to metal hydride storage.
At the University of California, Riverside researchers have discovered that carbenes, which mimic metals, may one day be used for hydrogen storage. Organic molecules called cyclic alkyl amino carbenes can be used to split hydrogen under mild conditions.
Government researchers also see high hopes for using doped carbon nanotubes for storing hydrogen. In other kinds of materials used, a strong bond exists between hydrogen and the other material. The goal for using carbon nanotubes is to establish a weak covalent bond so that the hydrogen can be easily accessed.
The U. S. Department of Energy (DOE) is also recently releasing $8.2 million for new hydrogen storage research. The DOE is already funding research into such areas as carbide-derived carbons, electron charged graphite-based storage material, novel organic clathrates and hollow glass microspheres.
Hydrogen storage is one of the key issues to the success of both the future hydrogen transportation system and the hydrogen economy. It all starts in the research labs, however, so it’s important to keep a watchful eye to see how this research unfolds.