A new battery developed by British scientists could pave the way to electric cars with the same energy storage capacity and endurance as petrol and diesel vehicles.

Compared with current batteries, it would also be a fifth cheaper and lighter.

The "lithium-oxygen" battery, built by Cambridge University researchers, is more than 90% efficient and has a very high "energy density" - meaning it can store a lot of extractable energy.

Although much work needs to be done, the technology could herald a transport revolution in the next decade as non-polluting electric vehicles become the most common sight on the roads.

Lead scientist Professor Clare Grey, from the university's Department of Chemistry, said: "While there are still plenty of fundamental studies that remain to be done, to iron out some of the mechanistic details, the current results are extremely exciting.

"We are still very much at the development stage, but we've shown that there are solutions to some of the tough problems associated with this technology."

Obstacles in the path of battery development have so far held back the adoption of clean technologies such as electric vehicles and grid-scale solar power.
Current lithium-ion batteries, used in laptops and smartphones, are light but have to be recharged often because of their low energy densities. Their capacity also deteriorates with age.

In contrast, the lithium-oxygen battery has a theoretical energy density which is 10 times higher and similar to that of gasoline.

However, building a working lithium-oxygen battery has proved a daunting challenge. Previous versions have been inefficient and unstable, tending to "die" after multiple charge and discharge cycles.

Another issue has been the formation of spindly lithium metal fibres which can cause batteries to short-circuit and explode.

The new demonstrator model from the Cambridge team, described in the the journal Science, incorporates several innovations to overcome these problems.
They include a carbon electrode made from graphene - a material made from one-atom-thick sheets of carbon - and additives that alter chemical reactions.

To date, the battery has been recharged more than 2,000 times.
"What we've achieved is a significant advance for this technology and suggests whole new areas for research," said Prof Grey.