https://www.bloomberg.com/news/features ... hey-retire
https://cleantechnica.com/2018/06/07/ye ... he-future/
https://www.powervault.co.uk/ (just as one example)
Recycling in the long term, possibly home electricity storage in the medium term. Google it for more info, it's all out there and there will be plenty of commercial incentive. They are extremely unlikely to end up in landfill like many small phone/laptop batteries do.
What, ultimately do you mean? After they've had eg 30-40 years' of use and reuse in different applications?
Given that they are nearly 100% recyclable, there isn't really anything to dispose of. Compared with most other things that we recycle (or simply put in landfill) they are actually pretty favourable.