Lithium Iron Phosphate batteries. (LiFePO4)

[light_emitting_dude]

Looks like some of these type batteries are availiable to buy. Just stumbled across these so if they are old news, sorry.

http://www.batteryspace.com/index.asp?PageAction=VIEWCATS&Category=1273

And it looks like they don't explode under extreme conditions. Interesting

 

[Fallingwater]

I'm afraid that's indeed old news. LiFe cells have been available at kai and DX for a while, and RC enthusiasts have been ripping A123 LiFe cells out of DeWalt battery packs for months.

 

[NA8]

I think the biggest negative is the low capacity, relatively short run time.

Here's a chevrofreak P2D run time review using a AW 500mAh.

http://www.candlepowerforums.com/vb/showthread.php?t=163405