If you can't manage to remove the battery by only using high concentration isopropyl alcohol (over 90%) you can try a combination with heat. In this case prepare an iOpener and apply it to the rear glass for at least two minutes to loosen the adhesive underneath the battery.

Insert a plastic card underneath the right edge of the battery.

Slide the plastic card along the right edge of the battery to separate it from the midframe.

Use your plastic card to pry up the battery.