Sorry to burst your bubble,
Sorry to burst your bubble, but cars rarely, if ever go into landfills. Even non-functional, wrecked, or just too-old-to-maintain cars are still worth their weight in steel, aluminum, lead, copper, rubber, etc to just get buried in the ground in some field. Those 'polluting' batteries will be recycled with the rest of the valuable materials in the car by a salvage yard. What do you think happens with your regular lead-acid battery when it dies in your car now?