Renovation of LiCoO2 with outstanding cycling stability by thermal treatment with Li2CO3 from spent Li-ion batteries

- LiCoO2 was renovated by thermal treatment with Li2CO3.
- The ratio of Li/Co can fluctuate within a certain range in the process of renovation.
- The ratio of Co3+ in the cathode material increases during the renovation process.
- A proper amount of Al and Cu residue improve the electrochemical properties.

It is quite necessary for us to pay close attention to the recycling of the spent Li-ion batteries as the worldwide consumption of Li-ion batteries grows year-on-year, and the recycling process today is relatively complex and environmental harmful. So a simple and green recycling process is needed. An acid-free recycling process is proposed and used to recycle spent 18650-type LiCoO2 batteries, and the recycled cathode material has been renovated by thermal treatment with Li2CO3. After dismantling, detachment of an 18650 cell and renovation of pristine cathode material, we recovered plastic, stainless steel, separator, Cu foil, Al foil and renovated cathode material. The total recovery weight ratio could reach 95.78%. X-ray diffraction patterns and Raman spectroscopy show that the compositions of the pristine cathode material are LiCoO2 and Co3O4. X-ray photoelectric spectroscopy shows that Co3O4 decreased during the renovation process. The mole ratio of Li/Co has been adjusted in the process of renovation to obtain the optimal properties. The initial discharge capacity of the renovated cathode material is 150.3 mA h/g and delivers a discharge capacity of 140.1 mA h/g after 100 cycles with outstanding cycling stability. The effect of impurities of Al and Cu elements has been evaluated on the electrochemical properties for the renovated cathode material. The results demonstrate that the impact of both elements is in acceptable range. This renovated cathode material by as-proposed method has good electrochemical characteristics for Li-ion batteries, which can possibly meet the commercial requirements for reuse.