Oriented conversion of spent LiCoO2-lithium battery cathode materials to high-value products via thermochemical reduction with common ammonium oxalate

Recycling critical metals from spent Li-ion batteries (LIBs) is essential for the overall sustainability of future batteries. This study presents a refined thermochemical reduction-assisted water leaching approach to efficiently recover lithium and cobalt from spent LiCoO2 LIBs using ammonium oxalate as the only reducing agent. Through thermochemical reduction, LiCoO2 was converted to Li2CO3 (water-soluble) and metallic Co (water-insoluble). After leaching with water, 99.63% lithium and 99.82% cobalt were obtained as Li2CO3 and metallic Co, with 99.74% and 98.95% purity, respectively. The thermochemical mechanism revealed that the thermochemical process consists of two different stages of ammonium oxalate decomposition and controlled reduction. High purity of metallic Co products can be acquired by regulating the amount of ammonium oxalate. These findings can inspire environmentally friendly and value-added recycling of metals from spent LIBs.