Batteries that breathe

With the launch of the Nissan Leaf and Chevy Volt, it´s been a big year for electric vehicles, but their batteries still have a fairly limited range without a recharge. For a car running on today lithium ion batteries to match the range provided by a tank of gasoline, you´d need a lot more batteries, which would weigh down the car and take up too much space. But what if you could take away one of the electrodes in a battery and replace it with air? Researchers estimate that a lithium-air battery could hold 5 to 10 times as much energy as a lithium-ion battery of the same weight and double the amount for the same volume. In theory, the energy density could be comparable to that of gasoline.