Recycling of spent LiCoO2 materials by electrolytic leaching of cathode electrode plate

Abstract With the rapid growth of the lithium-ion batteries (LIBs) market, it is meaningful to recycle spent LIBs for environments protecting the and resources save. In this study, a novel method is proposed for the leaching spent LiCoO2 material, recovery Al foil and separation cathode materials in one step by direct electrolytic leaching of spent electrode plate. The leaching efficiencies of 97.25 % for Li and 96.21 % for Co and only 6.85 % for Al could be obtained by electrolytic leaching under the optimized conditions of 2.5 mol/L DL-malic acid, 8 V voltage, 70℃ and 120 min. Kinetic analysis shows that the chemical reaction is the control step in the electrolytic leaching process. Furthermore, a series of studies on the mechanism of electrolytic leaching indicate that Co3+ can be reduced to Co2+ by electric reduction in the weak acid environment without reducing agent. Meanwhile, Al foil is protected by passivation and can be directly recycled. Finally, the recovered CoC2O4·2H2O from the filtrate is used for LiCoO2 regeneration. The regenerated LiCoO2 displays outstanding cycle performance and rate performance.