Amazon.com: i-Blason Battery Case Designed for iPod Touch 7/6/5, 2200mAh Portable Charging Rechargeable Extended Battery Slider Case for iPod Touch 5th/6th/7th Generation, Black : Electronics
iPod Touch (6th and 7th Gen) Battery: Replacement Part
Replacement batteries for Apple's iPod Classic, iPhone, Touch, Mini, Nano, 1st Gen, 2nd Gen, 3rd Gen, 4th Gen, and Video | iToolBatteryKit
Refurbished iPod touch 32GB Blue (6th generation) - Apple
About the battery usage on your iPhone, iPad, and iPod touch - Apple Support