Overlooked residue of Li-ion battery recycling waste as high-value bifunctional oxygen electrocatalyst for Zn-air batteries

Continuously increasing production of Li-ion batteries (LIBs) for the Green Transition is underlined by the absence of feasible recycling methods for graphite, regardless of its criticality as a raw material. The current study demonstrates a novel strategy to valorize waste graphite as a valuable raw material in oxygen electrocatalyst production. Industrially produced LIBs post-metallurgical leach residue was transformed into highly active bifunctional oxygen electrocatalyst, which was subsequently successfully applied as an active catalyst for Zn-air batteries. Moreover, produced graphene-like material was in-situ doped by the impurity cobalt present in the recycling residue. The resultant Zn-air battery was shown to deliver a high specific capacity of 719 mA h g^-1, peak power density of 112.8 mW cm^-2 and could be cycled over 400 times. Results clearly demonstrate that an often-neglected LIB recycling waste fraction can be a valuable source for electrocatalysts production required in metal-air batteries and regenerative fuel cells.