Recycling of mixed discarded lithium-ion batteries via microwave processing route

Abstract

The ever increasing demand, the short life span of lithium-ion battery (LIBs), the presence of critical metals, and environmental considerations make recycling inevitable. A short duration, cost-effective recycling process for discarded mixed cathode material, and microwave reduction of cathode materials using recovered graphite are investigated. In this work, cathode materials of discarded LIBs are treated in the microwave for recovery of metallic values. Cathode and anode sheets of spent batteries were pulverized, sieved separately, and the active cathode material was reduced in the microwave at different times, graphite dosage, and microwave power. The microwave response of cathode material and reductants (graphite and charcoal) is investigated. A comparative analysis of microwave reduction of pure (LiCoO2) and mixed (LiCoO2, LiNi0.5Mn1.5O4, LiMn2O4) cathode materials was carried out using both graphite and activated charcoal. The final product comprises Co: 71.6%, Mn: 8.5%, Ni: 6.3%, O: 13.6% with saturation magnetization of 91 emu/g, lithium extraction: 82% and process yield of 32%. The indigenous microwave carbothermal reduction based process is found to be successful, considering product quality and cost considerations.