pretty sure >10 years ago I had an array of aftermarket Li-Ion batteries for the Samsung Galaxy S2, which were able to be quickly swapped in and out when needed. there were same sized ones with slightly higher capacity than the one the phone came with, then there were double thickness ones with double the capacity that came with their own replacement battery cover. think they went up to 5000mAh. there were the usual Chinese 'gold' and 'fire' brands, but you could also pay a bit more for Japanese. they all worked and never swelled or exploded. perhaps I was just lucky. those were the days..