Battery breakthrough set to accelerate electric-car development

A team of scientists working at the Massachusetts Institute of Technology are claiming a significant breakthrough in recharging times for lithium-ion batteries.

According to findings published in the scientific journal Nature, MIT researchers Byoungwoo Kang and Gerbrand Ceder have unlocked the potential of lithium-ion batteries by patenting a unique process which is claimed to allow a typical laptop power pack to be fully recharged in less than a minute--an improvement in recharging performance of roughly 90 percent over existing lithium-ion batteries.

Lithium-ion batteries generate electric current via the flow of lithium ions across an electrolyte, from an electrode to a cathode. Recharging them effectively reverses this process; lithium ions are sent from the cathode back to electrode.

The recharge time of lithium-ion batteries in use today is limited by how quickly the lithium ions pass through the electrolyte.

The process being championed by Kang and Ceder sees the lithium ions used in the cathode coated in lithium-phosphate glass to help speed up the time it takes for the ions to pass from cathode to electrode. Lithium-phosphate glass is a highly efficient lithium conductor, subsequently helping to accelerate the recharging process.

Ceder says the new process creates "perfectly sized tunnels for lithium to move through." He adds, "We saw that we could reach ridiculously fast charging rates."

Improving recharging times has long been considered the route to making hybrid drive systems more efficient. By taking advantage of the process developed by Kang and Ceder, lithium-ion batteries could be recharged in a matter of minutes via the gasoline engine and/or during braking while on the move. It also could make electric vehicles much more practical by extending their range and reducing the amount of time they need to be plugged in to external charging sources.

Read the Nature article: http://www.nature.com/news/2009/090311/full/news.2009.156.html

By Greg Kable