Mostly lithium AA's are the Energizer brand (aka, the L91). There's the Titanium and the "blue/silver" style. These are replacements for alkalines and should be interchangable with any AA.

There ARE Li-ion batteries in AA size, called 14500s. Those have a higher energy capacity, and I don't think are completely interchangable, despite the same size - higher amps or volts or something. (sorry, I'm a doctor, not an electrician)