Most are already fully recycled today.
With NiCd and button batteries, there are no longer any problems.
A major problem, however, are the mercury batteries still on the market, because current processing machines can only process 100% mercury-free batteries.
Since the production and thus sale of batteries containing mercury has been stopped for several years, this problem can be expected to solve itself soon.

This month was THE boat reveal of TU Delft’s Hydro Motion Team and we are proud battery sponsors there. See below the boat the students designed themselves, which contains the battery.