Selective lithium extraction and regeneration of LiCoO2 cathode materials from the spent lithium-ion battery

Due to the mounting pressure to mitigate environmental pollution and guarantee the sustainability of the battery metals, the recycling of spent lithium-ion batteries (LIBs) has become a crucial issue in recent years. Numerous studies have focused on utilizing high temperatures or strong acid/alkali to reduce the spent active cathode material to a low valence state, which exacerbates recycling and post-treatment costs. Herein, a low-temperature roasting process followed by a water leaching strategy is developed to recycle and regenerate LiCoO2 cathode material from spent LiCoO2 batteries. The spent LiCoO2 is roasted with glucose (C6H12O6) as a reagent to attain reduction of the cathode material into water-soluble Li salt (Li2O and Li2CO3) and water-insoluble (Co and CoO). The proposed method utilizes moderate roasting temperature and water as the only leaching reagent, which effectively reduces energy and chemical consumption. Li and Co recovery rates are 97 % and 99 %, respectively, under the optimal conditions of 1 h roasting at 550 °C followed by 30 min water leaching using a solid–liquid ratio of 50 g/L. The recovered Li-rich solution and Co-rich residue can be easily converted to Li2CO3 and Co3O4, respectively, which are the precursors for regenerating the LiCoO2 cathode material. The regenerated LiCoO2 exhibits superior cycling stability with 87 % capacity retention after 800 cycles at 4.4 V. This developed closed-loop recycling process has lower recycling costs, is eco-friendly and efficient, and thus could potentially promote the sustainable long-run development of the LIBs industry.