Low-Temperature Hydrothermal Relithiation of Spent Lithium-ion Battery Cathodes by Redox Mediation

A process for low temperature hydrothermal relithiation of spent lithium-ion battery cathode materials adds a reducing agent to an aqueous Li solution at 80-100° C. followed by a short anneal to achieve complete recovery of composition, crystal structure, and electrochemical performance for heavily degraded cathode materials.