Replaced the dead battery in an old iPod Nano I bought (really wanted a cheap Product Red one) and not even 2 days later the replacement battery expanded. I would call this
Apple iPod Nano 2nd Generation - 2GB Silver (Replaced New-Battery ) Best Gift | eBay
Apple iPod nano 2nd Generation Silver (2 GB) New Battery Fully Functional | eBay
Original Battery For Ipod Nano 1 2 3 4 5 6 7 4th 5th 6th 7th 1st 2nd Generation 2 Gen 2gen 3rd 3 Gen 3gen + Free Tools - Mobile Phone Batteries - AliExpress