Although a practical lithium-air battery is still some years from becoming a commercial reality, researchers at the University of Cambridge have developed a working laboratory demonstrator that shows how many of the problems holding back the development of lithium-air batteries could be overcome.

Because they "breathe" oxygen from the air to power the chemical reactions that release electricity rather than storing an oxidizer internally like lithium-ion batteries do, lithium-air batteries boast an energy density comparable to gasoline. This would allow an electric car with a battery one-fifth the cost and weight of those presently on the market to drive 400 miles (650 km) on a single charge.

That's the theory anyway. The problem is, practical attempts so far to develop the lithium-air battery have not yielded great results, despite efforts from the likes of IBM and MIT. Until now, these attempts have resulted in low efficiency and poor rate performance, instability and unwanted chemical reactions. In an attempt to overcome these problems, researchers from the University of Cambridge created a battery that uses a different chemistry to previous designs.