Better batteries? The answer is blowing in the wind…

A new generation of electric cars, mobile phones and laptops could be just around the corner thanks to a new kind of air powered battery.

Diagram of the STAIR (St Andrews Air) cell. Oxygen drawn from the air reacts within the porous carbon to release the electrical charge in this lithium-air battery

Researchers at the University of St Andrews with partners at Strathclyde and Newcastle have developed a new type of air-fuelled battery could give up to ten times the energy storage of designs currently available.

The battery offers improved capacity is thanks to the addition of a component that uses oxygen drawn from the air during discharge, replacing a chemical constituent used in rechargeable batteries today. Not having to carry the chemicals around in the battery offers more energy for the same size battery. Reducing the size and weight of batteries with the necessary charge capacity has been a long-running battle for developers of electric cars.

Principal investigator on the project, Professor Peter Bruce said: “Our target is to get a five to ten fold increase in storage capacity, which is beyond the horizon of current lithium batteries. Our results so far are very encouraging and have far exceeded our expectations.”

“The key is to use oxygen in the air as a re-agent, rather than carry the necessary chemicals around inside the battery.”

The STAIR (St Andrews Air) cell should be cheaper than today’s rechargeables too. The new component is made of porous carbon, which is far less expensive than the lithium cobalt oxide it replaces. The four-year project - which reaches its halfway mark this month - builds on the discovery at the university that the carbon component’s interaction with air can be repeated, creating a cycle of charge and discharge. Subsequent work has more than tripled the capacity to store charge in the STAIR cell.

The oxygen, which will be drawn in through a surface of the battery exposed to air, reacts within the pores of the carbon to discharge the battery. “Not only is this part of the process free, the carbon component is much cheaper than current technology,” says Bruce. He estimates that it will be at least five years before the STAIR cell is commercially available.