THE next generation of plug-in hybrid cars could recharge in minutes, thanks to a new type of battery.

Lithium ion cells are used in portable gadgets and the latest hybrid cars as they are light and can be repeatedly charged and discharged with little degradation. But as with all batteries, charging takes some time. That's because it involves detaching lithium ions from the cathode at one end of the battery and absorbing them at the anode; pulling the ions from the cathode is normally a slow process.

Now Byoungwoo Kang and Gerbrand Ceder at the Massachusetts Institute of Technology have revealed an experimental battery that charges about 100 times as fast as normal lithium ion batteries. Their battery contains a cathode made up of tiny balls of lithium iron phosphate, each just 50 nanometres across. The balls quickly release lithium ions as the battery charges, which travel across an electrolyte towards the anode. As the battery discharges, the lithium ions move back across the cell to be re-absorbed by the nanoballs.