Yeah, I picked them up along with some AA lithium (non-rechargeable) batteries. I also didn't know those batteries existed until recently. I knew there were rechargeable lithium AAs with a charge plug and charging circuitry built into each little cylinder, but I've heard mostly bad reviews of those.

These non-rechargeable ones have pretty good reviews though, and apparently last much longer than normal AAs (both in terms of capacity and storage). I'll probably start putting them in the handful of things I've got that still take AAs.