Redox Mediator Relithiation of End-of-Life Lithium-Ion Battery Cathode Materials

Abstract

Lithium-ion batteries (LIBs) are ideal for electric vehicles and electronic devices because of their high-power density and outstanding cycle life. The need for recycled LIBs material is pivotal for the sustainability of the renewable energy industry. The recycling process needs to be both economically and environmentally conscious. Direct recycling is cheaper and generates the least amount of waste compared to pyrometallurgical and hydrometallurgical processes.Direct recycling explored in this work is useful for reclaiming precious minerals from the End-of-Life (EOL) LIBs material. Redox mediator relithiation restores the lithium content rapidly and at low cost without sensitivity to EOL material with varying lithium deficiency. The redox mechanism relithiates EOL cathode material by shuttling charges very fast between lithium metal and EOL cathode material. The redox mediator is oxidized to create lithium rich solvent and reduced to relithiate EOL cathode material. However, the process is sensitive to pH changes. The redox reaction creates acidic solvent, which may cause lithium leaching. Therefore, use of lithium hydroxide (LiOH) to remove impurities on the surface of the EOL material and as a lithium source creates a basic solution to prevent lithium leaching and relithiate EOL material. This approach will potentially pave way for fast quality cathode material recovery at a low cost. Figure 1