A Japanese company called Eamex claims it has found a way [JP] to increase the life of high-capacity lithium-ion batteries (that can be used in electric vehicles). Eamex says the new batteries can be charged and discharged over 10,000 times. Apparently, they can last about 20 years, too.
http://www.crunchgear.com/2010/02/04/new-technology-extends-lithium-ion-battery-life/