Direct Regeneration of Spent LiCoO2 Black Mass Based on Fluorenone-Mediated Lithium Supplementation and Energy-Saving Structural Restoration

Degraded LiCoO 2 cathode from retired Li-ion batteries is urgently required to be recycled in a greener way for economic and environmental considerations. The coarse metallurgy technologies for Li/Co extraction with massive CO 2 emission and energy consumption cannot satisfy the requirements of carbon neutralization. Herein, it is proposed that direct regeneration of degraded LiCoO 2 cathode could be realized via 9-fluorenone-mediated Li supplementation and follow-up structural restoration. The 9-fluorenone-lithium reagent is elaborately selected to compensate for the missing Li + into lattice with targeted stoichiometry owing to its compatible redox potential of 1.95 V versus Li + /Li, which is located just between the reversible intercalation (3.8 V) and irreversible conversion (1.2 V) potentials of LiCoO 2 electrode. Then, thermal energy-driven structure reorganization enables Li/Co atoms to occupy the right sites, accomplishing desirable structure healing within a short annealing time of 4 h. The regenerated LiCoO 2 cathode exhibits comparable Li-storage capability to commercial LiCoO 2 , benefiting from the non-destructive direct regeneration technology. In addition, the regeneration route is regarded as environmentally (0.13 kg CO 2 kg −1 cell) and economically (10.07 $ kg −1 cell) superior to conventional recycling routes based on life-cycle analysis. The precise surgery on spent LiCoO 2 cathode provides a promising solution for the forthcoming retirement rush of Li-ion batteries.