Autoblog Green Podcast #4 - Altairnano CEO Alan Gotcher - A very interesting interview about the altairnano batteries, and the Phoenix SUT which is close to being sold.
The altairnano battery is li-ion, does not use cobalt and hence is not explosive. They use a nanoscale manufactured electrode they're saying is ultra safe. Their tests are a 6 minute (!!!) charge followed by a 6 minute discharge (!!!!) in a rapid cycle. So.. compared to normal charge/discharge tests where the rated capacity is based on a 20 hour discharge; this sounds totally phenomenal.
Unfortunately it doesn't sound from the interview that they'd be interested in selling batteries to individuals. And in any case their current cost is likely far higher than individuals like us would be willing to pay.