Multiple-Site Interaction-Driven Coordination Mechanism for Lithium-Ion Battery Cathode Recovery Using Water-Containing Intermediate-Strength Acid-Based Green Solvents

Abstract Current hydrometallurgical recycling technologies for spent lithium-ion battery (LIB) cathodes predominantly rely on single-site interactions, which suffer from obvious drawbacks including low leaching efficiency, excessive energy consumption, and usage of highly corrosive strong acids (e.g., sulfuric acid and hydrochloric acid). Herein, we propose a multiple-site interaction-driven coordination (MSIC) mechanism for spent LCO cathode recycling from LIBs using water-containing intermediate-strength acid-based deep eutectic solvents (DESs). The multiple-site interaction arises from the abundant hydroxyl and carbonyl coordination sites in the DESs formed by glycerol and water-containing phosphoric acid. Results show that the proposed MSIC mechanism achieves leaching efficiencies of 94.7% for lithium and 98.1% for cobalt from the LCO cathode under mild intermediate-strength acid conditions. This remarkable performance substantially outperforms conventional single-site interaction-based leaching, which requires harsh strong-acid environments accompanied by severe equipment corrosion and high operational risks.