It can be, it isn't happening currently: "As of 2017, the recycling of Li-Ion batteries generally does not extract lithium since the many different types of Li-Ion batteries require a different extraction process.[6] Another reason why it isn't being done is because the extraction of lithium from old batteries is 5x more expensive as mined lithium"
Even so when recycled it still creates toxic waste in large quantities. What shall we do with that?