A123 makes a pretty good lithium battery that has a high-cycle life and can put out loads of power. What it's not so good at, however, is holding a lot of energy. At least, not when compared to the Panasonic cells that Tesla Motors uses in the Model S. Sure, it's great for hybrids and city-car applications like the Chevy Spark EV, but if it's going to find a place in the longer-range EVs of the future, it will need to up its game. It looks like that could happen.
Long Range Batteries