Heavy batteries are the bane of many fuel-conscious drivers' existences -- the more weight you have in your vehicle, the more energy you'll need to move forward. That's why people tell you to unload any belongings from your car's trunk and back seat if you really want to save at the pump.
Recognizing this problem, many researchers have looked into making hybrid battery packs much lighter. A group at the Massachusetts Institute of Technology (MIT), for instance, has found a way to make lithium-ion batteries both lighter and faster. The original problem with lithium-ion batteries was their relatively slow release of energy. Scientists thought lithium atoms were moving too slowly through the battery material, but the MIT researchers think it might be the nano-scale size of the technology that's making it difficult for ions to travel.
A lithium phosphate coating helps speed ions along, making it easier for them to quickly reach the battery terminal. The new battery material also stops the packs from degrading as much, which means that manufacturers can keep the sizes of the batteries much smaller than before.
For lots more information on hybrid cars and battery technology, follow the links on the next page.