There's no such thing as a LiIon AA battery. Please point to a product page for one. The Philips light comes with NiMH batteries. Mine did, others have posted photos of them. I've checked multiple review sites and vendor sites. The only place LiIon ever shows up is on the Philips product page. I think it's a typo.

LiIon chemistry delivers 3.7 volts per cell. If you used the AA sized 14500 cells in the Philips, I do not doubt that you would fry the electronics immediately. It would be 15 volts instead of 5 volts for the pack.

Not working effectively below 32 degrees is a deal killer for me - apart from a few weeks in the spring and fall, the primary time when I need lights is below 32 degrees, and I don't think I'm alone. I still don't know why Philips is using NiMH - it's senseless. LiIon is better in every way and is not expensive anymore.