Thermochemically driven layer structure collapse via sulfate roasting toward the selective extraction of lithium and cobalt from spent LiCoO2 batteries

With the rapid development of new energy devices, a large amount of spent lithium-ion batteries (LIBs) are produced every year. Recovering valuable metals from spent LIBs is significant for achieving environmental protection and alleviating resource shortages. In this study, a novel approach by in situ thermal reduction technology with waste copperas is developed to recycle valuable metals from spent LiCoO2 (LCO) batteries. The mechanism study through in situ x-ray diffractometer and thermal analysis reveal that the sulfation of LCO underwent two pathways i.e., ion exchange and gas-solid reactions. In the ion exchange pathway, the layered structure of LCO collapse due to the reduction by divalent iron in copperas, and the detachment of lithium ions result in a larger lattice spacing of transition metal layer and formation of a stable spinel structure. Furthermore, the SO2 generated from the decomposition of iron sulfates reduces the unreacted LCO through gas-solid in-teractions, realizing the sulfation of lithium and cobalt completely. Economic analysis indicates the potential benefit of this process is approximately 8266$/t spent LCO. This study provides an alternative technological route and a new approach to green recovery of the spent LCO batteries, exhibiting great potential for wide applications.

Automated summary

With the rapid development of new energy devices, there is a need to recycle valuable metals from the large amount of spent lithium-ion batteries (LIBs) produced every year. In this study, a novel approach using in situ thermal reduction technology with waste copperas was developed to recycle valuable metals from spent LiCoO2 (LCO) batteries. The mechanism study revealed that the sulfation of LCO underwent ion exchange and gas-solid reactions. Economic analysis indicated the potential benefit of this process.