My ipod dies so quickly after I have it on charge. why?

I have an Ipod. I can have it on chart for about two hours, I take it off and it only lasts about 10-15 minutes before dying. I looked on the internet and it says if you have a lot of extra stuff on it then it dies. Well I have barely any apps, I deleted most of them, and I have barely any pictures, I deleted most of them. I don't know what to do.

Most likely it has a defective battery.

Before going to Apple store to fix your iPod battery, you can try using iTunes to restore your iPod. But note that it will cause data losing. And there is a better tool to fix your battery issue - TunesKit iOS System Recovery.
See more in: https://www.tuneskit.com/ios-system-recovery-for-mac.html