Highly efficient degradation of emerging pollutants using cobalt oxide recovery from spent LiCoO2 batteries through autocatalytic lithium extraction

Increasing number of spent lithium-ion batteries (LIBs) presents opportunities and challenges for the recycling of cathode LiCoO 2 (LCO). Here, simultaneously selective leaching Li and fabricating cobalt oxide catalyst was developed by autocatalytic Peroxymonosulfate (PMS) advanced oxidation method at ambient temperature without strong acids. Where, superoxide radical ( O 2 · - ) was generated to break Li-O leaching 96.6 % of Li, and induced part conversion of Co 3+ to Co 2+ forming oxygen vacancies (O V ) in the remaining Co-containing product (NLCO). Compared with LCO (without delithiation), NLCO promoted greater electron transfer to activate PMS producing radical ( SO 4 · - and •OH) and non-radical ( 1 O 2 and Co(Ⅳ)=O) in the degradation of emerging pollutants (carbamazepine, CBZ). Hence, the NLCO/PMS system was effective in removing CBZ with resistance to pH variation and water matrix interference ( SO 4 2- , NO 3 - , and HA). COHP calculation results revealed the strong and almost unbreakable Co-O in NLCO, with significantly low Co leaching ensuring the excellent stability (100 % degradation activity maintained after 7th cycling) for removing pollutants in the liquid-phase reaction. Degradation pathways and toxicity analysis elucidated that the NLCO/PMS was a green and toxicity reduction process for removing CBZ. This study showcased a novel method for recovering Li from spent LCO and subsequently producing an environmental catalyst form spent LIBs.