Storage solution

A chance discovery has paved the way for devices that can store and release hydrogen at the flick of a switch, bringing practical, fuel-cell cars a step closer.

The much-vaunted hydrogen economy, in which industrialised nations no longer need to depend on oil, will only emerge when three basic problems have been solved — the efficient production, distribution and storage of the gas itself.

The last of these three is perhaps the biggest barrier for the development of fuel-cell vehicles. Hydrogen is notoriously difficult to contain. Its molecules find their way through many materials and can cause embrittlement in the process. This is exacerbated when storage density is boosted by keeping it under pressure.

One alternative is to lock hydrogen molecules into the lattice structure of a metal hydride but this poses more problems. Hydrides only release the trapped gas at temperatures above 300ºC.

Another option is to use porous polymers to soak up hydrogen molecules like a sponge (