I have been looking into batteries recently for an application where I need high capacity and roughly a 10 year lifespan. Oh and they have to work at extreme temperatures (-60 C to 50 C would be sweet), and be priced reasonably. Lithium SOCl2 is a cool chemistry which fits the bill, but is hazmat. I think Lithium Manganese ones are a decent compromise. Does anyone have any better ideas?
The local transit-cops seem to like them for adding weight to their billy-clubs. A secondary function seems to be to make one end of the clubs light up, but a pocket LED flashlight is usually way brighter.
