Well the electrolyte solution is water based so exceeding the boiling point will cause pressure buildup inside.
Edit: hmm seems I might be generalizing too much. Not all batteries use water based solutions. My point is that you should avoid a pressure buildup inside the battery due to reaching the solvents' boiling point.
Well it was my 4th LG G4. Four times a charm I guess.
Sounds like a horrible idea if not carefully controlled. Perhaps up to 80 degrees in an oil bath could redissolve some of the electrolytes. I guess it could work. Anything above 100 is asking for trouble.
For me that was not so long ago. I still used an LG G4 as permanent car navigation until a year ago or so. I'm still surprised that one didn't end up bootlooping.
Popup #10000: Have you tried feature X that nobody asked for yet?
Good point. It's highly concentrated inside a battery if not saturated. Hmm. I still wouldn't expose them to such high temperatures.
Perhaps a longer duration at lower temperature is safer. I might try it some day with some waste batteries and a battery tester.