Efficient non-destructive recovery of LiFePO4 from spent lithium-Ion batteries for high-purity regeneration

Abstract

Following mechanical shredding of spent lithium-ion batteries (LIBs), the complex composition of electrode materials hinders subsequent recycling. Thus, the separation of cathode and anode materials is a crucial step in the recycling process. The separation efficiency of cathode and anode materials under the two pretreatment methods of oxygen-free roasting and water soaking was analyzed by testing and calculation. Based on the different pyrolysis characteristics, the pretreatment process through oxygen-free roasting achieved high-purity separation, yielding anode and cathode materials with purities of 98.5 % and 93.3 %, respectively. By exploiting the water solubility differences of the binders, soaking the electrode sheets in water for 75 min followed by 40 KHz frequency ultrasonication for 1 min before sieving results in a purity of up to 98.7 % for the anode material and 98.1 % for the cathode material. Additionally, the anode material’s lithium leaching rate during water soaking separation is 82.9 %, supplying raw material for cathode repair and regeneration. Furthermore, the initial charge–discharge specific capacity of cathode material separated by water soaking is around 150 mAh/g after lithium replenishment, which is significantly higher than that of cathode material separated by oxygen-free calcination. A novel process for separating cathode and anode materials through water soaking and ultrasonic vibration was ultimately developed. This process not only enables the efficient separation of LiFePO₄ cathode materials but also facilitates their high-value regeneration. This method offers a scalable and environmentally sustainable approach to LIB recycling, with potential applications in industrial-scale battery material recovery.