Phone only works when plugged in charger

[AC Question]

I was using my phone fine, it had a full battery when all of a sudden it just shut off. I turned it back on, it said connect to charger, then shut off. I connected it to the charger turned it back on and it started working fine and said battery charged, so I unplugged it and within 5 seconds it shut off. Is my battery shot, or something else?

 

[Golfdriver97]

I was using my phone fine, it had a full battery when all of a sudden it just shut off. I turned it back on, it said connect to charger, then shut off. I connected it to the charger turned it back on and it started working fine and said battery charged, so I unplugged it and within 5 seconds it shut off. Is my battery shot, or something else?

What device do you have>