Sodium sulfite roasting for preferential lithium extraction from cathode material of spent lithium-ion batteries

Abstract

Spent lithium-ion batteries can be recycled to effectively re-utilize them. This can be conducive to secondary resource utilization as well as environmental protection. Here, it is suggested to roast the spent cathode materials with sodium sulfite to extract lithium more effectively. Under the ideal circumstances of a roasting temperature of 750 °C, the molar ratio of Na2SO3 to spent cathode material of 3.0, and a roasting period of 2 h, the leaching efficiency of Li reaches 94.06%. During the sodium sulfite roasting process, the spent LiNi0.6Co0.2Mn0.2O2 materials were transformed into LiNa(SO4), LiMnO2, NiO, LiMn2O4, Co9S8, and Ni, Co, and Mn. The LiNi0.6Co0.2Mn0.2O2 materials that were produced using the recovered Li2CO3 exhibit good electrochemical performance. The closed-loop process based on Sodium sulfite roasting is expected to be applied in the recycling industry of spent lithium-ion batteries.