Evaluation of carbothermic processing for mixed discarded lithium-ion batteries

Abstract

The limited life span and huge demand for lithium-ion batteries, environment concerns, and the consumption of rare metals such as lithium and cobalt are the key facts for the worldwide recycling efforts. In this study, the cathode material of discarded lithium-ion batteries was carbothermally reduced using recovered graphite. A comparative evaluation of reduction behavior of single-phase (LiCoO2) and mixed-phase (LiCoO2.LiNi0.5Mn1.5O4.LiMn2O4) cathode materials was investigated under an ambient and inert atmosphere. Processing of single-phase cathode material in inert atmosphere yielded pure metallic cobalt, whereas, higher metallic recoveries and metal purity were obtained by processing of mixed cathode material in ambient conditions. The excellent product obtained under ambient conditions comprises 68% Co, 21% Mn, 2.5% Ni with saturation magnetization: 106 emu/g, and a precursor for the synthesis of cathode material. The process yield is 46.2% and lithium extraction 83%. In terms of metal purity and recovery, graphite was found to be better for reduction than activated charcoal. The process followed is simple, adaptable, and cost-effective for metals recovery from discarded lithium-ion batteries.