Repeat for the second strip.

If you removed both strips successfully, skip the next step.

If the adhesive breaks off underneath the battery and can't be retrieved, apply a few drops of high concentration (over 90%) isopropyl alcohol under the edge of the battery in the area of the broken adhesive strip(s).

Wait about one minute for the alcohol solution to weaken the adhesive. Use the flat end of a spudger to gently lift the battery.

Don't try to forcefully lever the battery out. If needed, apply a few more drops of alcohol to further weaken the adhesive. Never deform or puncture the battery with your pry tool.

Do not pry against the logic board or you may damage the phone.

Avoid prying at the top left near the volume controls, or you may damage the volume button ribbon cable.

You can also try the alternative methods in the next step.