This company has a quiet advanced Lithium battery.

http://www.polyplus.com/technology/lithiumaircell.htm

What they are proposing is indeed quiet amazing. The theoretical
limit goes straight up above the 6000 Wh/Kg of the Lithium-
Fluorine "coast to coast" battery to an unheard off value of 11600
Wh/Kg for their Lithium-Air battery.
To put this in perspective, that would also make a "coast to coast"
battery, except that this time we would be talking about going from
the west Europe coast to the China east coast instead of the
more "conventional" California coast to New-York coast.
Present batteries are "only" in the 200 Wh/Kg figures.

Here is an article about Polyplus I found back on the web:

http://jcwinnie.biz/wordpress/?p=1015

It looks like we could soon forget not only about oil but also about
biofuels and hybrids alltogether if this battery comes to market.

Patrick