...like a Milaana or Lil'Bud in fact.
Thanks Bro!!!It's more a matter of buying from a reputable source than anything else. If you know your source, you know you'll get genuine A-grade cells, then you just have to select the model that has the required discharge rate and pick the one with the highest capacity.
Avoid ebay, amazon and aliexpress like the plague. Avoid anything with "fire" in the name. Only buy from the 4 OEM's and not rewraps, you'll pay less and you'll get A-grades and not whatever rejects the rewrappers managed to snatch. The 4 OEMs that actually build cells are LG, Samsung, Sony (MuRata) and Panasonic (Sanyo) anything else is a rewrap.
As for sources try ILUMN, IMRbatteries, batterybro or in Europe nkon or akkuteile. If you really want to buy from China, there are real cells on fasttech but make sure the product title includes the word "authentic" as they carry a lot of counterfeit products too.