MODELING AND EXPERIMENTAL INVESTIGATION OF REGENERATING THE MIXED CATHODE ACTIVE MATERIALS OF SPENT LITHIUM-ION BATTERIES

Abstract

The recycling of rechargeable Lithium-ion batteries (LIBs) has attracted more attention in the past few years due to its tremendous advantages to the economy and environment. Yet, there are three methods of recycling LIBs: hydrometallurgy, pyro-metallurgy, and direct regeneration. However, none of the currently developed recy-cling methods are completely economical for all materials of spent LIBs. Direct re-generation could be more economical if it is applied for all components of LIBs to-gether in one process. Since all types of LIBs are usually recycled at the same time without sorting them considering the chemistry of the electrodes, it's logical to either separate these types from each other to be further regenerated individually or doing the regeneration for all types together in one process. In this thesis, we show that the anode and cathode mixture materials that come from the most used types of LIBs (LiFePO4 (LFP), LiMn2O4 (LMO), LiNi0.33Co0.33Mn0.33O2 (NMC), LiNi0.8Co0.15Al0.05O2 (NCA), and LiCoO2 (LCO)) can be easily and effectively sepa-rated, and the resulted cathode mixture materials can be directly treated to be used to build new LIBs. In this thesis, a comprehensive physical recycling process is proposed to sepa-rate each component of the spent LIBs. The proposed process starts with separating the cathode mixture and anode materials came from different type of LIBs by adopt-ing Stokes’ law for mineral separation; then, the recovered cathode mixture is regen-erated through a process involving heat treatment and lithiation. The modeling and experimental results confirm that (a) the complete and rapid separation of the anode and cathode mixture materials from each other is possible, (b) the cathode mixture can be regenerated to make new LIBs, (c) the electrochemical performance of the regen-erated cathode mixture can be simulated, and (d) the capacity of the half-cells built from both regenerated cathode mixture and fresh cathode mixture materials are rela-tively close to each other indicating the validity of the regeneration model.