NaOH-Assisted Roasting for Corecovery of Spent LiFePO₄ and LiCoO₂ Batteries

Additive-assisted roasting has proven to be an effective strategy to improve metal recovery and decrease pyrometallurgical temperatures in the recycling of spent lithium-ion batteries (LIBs). However, excessive usage of additives and polluting exhaust emissions still need to be resolved. Here, a corecovery approach based on NaOH-assisted roasting is proposed for the recovery of valuable metals from spent LiFePO₄ and LiCoO₂ batteries, wherein NaOH is used as a roasting agent to destroy the structure of LiFePO₄ and generate Fe(OH)₂ to reduce LiCoO₂, separating Fe and Co from Li that is in the form of phosphates (Li_xNa_yPO₄). Hence, 94.8% of Li can be selectively separated by water leaching and recovered as Li₃PO₄ by stepwise evaporation and crystallization. By Everbatt model analysis, the NaOH-assisted roasting process is a promising candidate for the economic, environmental, and efficient recovery of LIBs with high utilization of additives and low emissions.