Can you please clarify.
[guide|6082]
Looking at the battery replacement guide, the aluminum foil is on the back of the lcd display and not the motherboard. You can replace the shielding with aluminum tape available at your local home improvement department.
If you are specifically referring to the copper pads covering the screws, you can purchase copper tape from online vendors.
FYI - There shouldn't have been any adhesive on the battery on the LCD side.