Rejuvenating the Electrochemical Performance of the Spent LiCoO2 Cathode Active Materials for Li-Ion Batteries

The direct regeneration method is regarded as the most promising recycling technique since it restores the cathode active material to its original form, making it immediately reusable in lithium-ion cells. However, direct regeneration methods reported in the literature often require lengthy, multistep procedures or preheat treatment, resulting in greater complexity, extended reaction times, and higher costs. In this paper, we have designed a versatile direct regeneration process in which we eliminated the complex nature of postprocesses such as active and nonactive material separation. We have investigated the compositional and structural properties of the regenerated LiCoO2 (LCO) cathode active material via scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques and carried out the electrochemical measurements through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) along with cycle life and rate tests. We refined the method by optimizing the temperature and duration of the heat treatment. The best electrochemical performance from the regenerated LCO was obtained after the heat treatment at 850 °C for 15 h. This cathode delivered a capacity of 134.7 mAh/g at 2C, with a capacity retention of 92% after 200 cycles, demonstrating excellent performance. We have presented a straightforward, scalable, environmentally friendly, sustainable, and cost-effective direct regeneration process.