It’s possible to get lithium non-rechargeable batteries. They are supposed to last longer. I had some when I got my last camera. They do last longer than the alkali ones, but cost more and didn’t seem, to me, to last long enough to warrant the extra cost. Those might be the ones you are supposed to use the switch for (if you have a switch).
The rechargeable AA batteries, I believe are mostly NiMH (Nickel Metal Hydride). Ordinary cameras, mobile phones, etc., tend to have Lithium rechargeable batteries, but they are the sort of oblong, fairly flat ones rather than the AA ones.
