Battery replacement

Possibly but only if it could not maintain, at least, an 80% charge after 500 full recharging cycles. If that is the case, take your iPhone to your local Apple Store or Apple Authorized Service Provider and let them take a look and provide you with your options.

• iPhone Battery and Performance - Apple Support

If it's maximum capacity % is close to 80%, then yes, make an appointment and have your device inspected at an Apple Store or AASP (Apple Authorized Service Provider) among this list:--> Apple – Location Selector

After checking it out, they'll give you all the available options.

Regards

Giulio