US researchers claim to have developed a safe and robust way of storing hydrogen and releasing it for on-demand use in fuel cells for cars.
Prof Travis Williams and colleagues from the University of Southern California (USC) devised a way to efficiently catalyse the release of hydrogen from ammonia borane.
Hydrogen fuel cells are now a relatively mature technology; however, as a gas, hydrogen can generally only be stored in high-pressure or cryogenic tanks. As Williams noted, in the case of a vehicle with a tank full of hydrogen, this could be a problem in the event of a collision.
Because of this, several groups have taken an interest in trying to use ammonia borane — a nitrogen-boron complex that can be stored as a stable solid — as a fuel.
However, until now it has proved difficult to efficiently produce enough hydrogen from boron compounds to make them viable for use in conjunction with fuel cells.
The team has developed a catalyst system that releases enough hydrogen from its storage in ammonia borane to make it usable as a fuel source. Moreover, the system is air stable and reusable, unlike other systems for hydrogen storage on boron and metal hydrides.
‘Ours is the first game in town for reusable, air-stable ammonia borane dehydrogenation,’ Williams said.
The catalytic system is sufficiently lightweight and efficient to have potential fuel applications ranging from motor-driven cycles to small aircraft.
The research was funded by the Hydrocarbon Research Foundation and the National Science Foundation. The USC Stevens Institute for Innovation is in the process of patenting the system.