RENEWABLE ENERGY AIR-FUELLED BATTERIES:RESEARCH INTO high-capacity air-fuelled batteries is producing encouraging results that could pave the way for a new generation of mobile phones, laptop computers and electric cars.
Funded by the UK's Engineering and Physical Sciences Research Council, researchers at the University of St Andrews are halfway through a four-year research project that may see batteries with 10 times the capacity of current designs become commercially viable.
If successful, the new design has the potential to improve the performance of portable electronic products, electric cars and give a major boost to the renewable energy industry.
Mobile phone batteries, for example, are currently comprised of a graphite negative electrode, an organic electrolyte and lithium cobalt oxide as the positive electrode. When a battery is charged, lithium is removed from the layered intercalation compound of lithium cobalt oxide, and re-inserted as the battery is discharged.
On discovering that lithium cobalt oxide limits energy storage, the researchers at St Andrews replaced it with a porous carbon electrode, which is far less expensive. This means oxygen can be drawn from a surface of the battery that is exposed to air.
The carbon component's reaction with air can be repeated to create a cycle of charge and discharge, meaning batteries designed in this way could enable a constant cycle of power output when combined with a solar panel or wind turbine, for example.
The design also eliminates the need to carry lithium in a battery, which means batteries could become far lighter. It would also increase the distance that an electric car could travel on one charge, for example.
Principal investigator on the project, Prof Peter Bruce of the chemistry department at St Andrews, says: "Our target is to get a five- to ten-fold increase in storage capacity. 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. Not only is this part of the process free, the carbon component is much cheaper than current technology," says Bruce.
