Ultimately, you can smelt them. It's not very economical, but the elements don't go away.
Ideally, you'd be able to 'refresh' the electrode material inexpensively. This involves removing lithium plating from the anode, and oxidized electrolyte from the cathode. This isn't a mature process, and it won't be until battery chemistries and manufacturing get more standardized and scale up. But there aren't strong theoretical reasons why this should be uneconomical. These issues take place at the surface of the electrode grains, and can likely be solved with bulk treatment. It's still going to require a fair amount of work to harvest the electrode material, but materials cost is a large percentage of battery production.
Ideally, you'd be able to 'refresh' the electrode material inexpensively. This involves removing lithium plating from the anode, and oxidized electrolyte from the cathode. This isn't a mature process, and it won't be until battery chemistries and manufacturing get more standardized and scale up. But there aren't strong theoretical reasons why this should be uneconomical. These issues take place at the surface of the electrode grains, and can likely be solved with bulk treatment. It's still going to require a fair amount of work to harvest the electrode material, but materials cost is a large percentage of battery production.