An electric car that actually goes far?

July 20, 2012

The performance of new lithium-air batteries is nearly unchanged after 100 charge and discharge cycles, which could bode well for their future use in electric vehicles. (credit: (car) Tony Hisgett/Wikimedia; (graph) Adapted from Z. Peng et al./Science)

Researchers have made the first stable lithium-air batteries, Science NOW reports. They may one day give electric cars a driving range similar to today’s gas guzzlers.

Lithium-air batteries have potential to store 10 times more energy than the best lithium-ion batteries on the market today, but have been unstable, falling apart after a few charges.

So researchers at the University of St Andrews in the United Kingdom replaced the conventional carbon-based cathode material with one made from inert gold nanoparticles that they hoped would be more stable. They also replaced the electrolyte — previously made from compounds called polycarbonates or polyethers — with one made from a common conductive solvent abbreviated DMSO that previous studies had shown may be less prone to react at the cathode.

The new combo worked: the new batteries were stable for 100 charge and discharge cycles with only a 5% loss of power.

But the new lithium-air batteries aren’t yet ready for commercialization. Gold is too heavy and too expensive to serve as the only cathode material in a practical cell. And over time, DMSO can react with lithium metal at the anode causing the electrolyte to break down.