My 2006 S6 batteries are starting to not last all day like they used to. Not sure why, they are only 11 years old (!!).
Can they be recelled? Probably not, they have some kind of electronics in there, but wondering if any company can rebuild them?
Thankfully for me, I believe that I am years away from that question. Basically though, If you can get the case open so that you can glue it back together, you can re-cell it. You will, more than likely, find three cells that are soldered and siliconed in
Being Lithium Ion batteries I would not want to attempt a recell. I would also assume the case for the battery would not come apart easy enough to avoid damage.
The price of a new battery is $160. If you buy new make sure you get the latest 70wh capacity battery as they last much longer than the previous, and work with your S6.
Arthur Dias is your man to go to IMVHO as he understands.
http://www.batteryrevival.com/
Cheers,
Derek