Microwave-assisted methanol-sulfosalicylic acid leaching system for efficient and closed-loop lithium-ion battery cathode recycling.

Effective recycling of spent lithium-ion batteries (LIBs) is critical to mitigating resource scarcity and environmental degradation amid rising global demand for energy storage. However, LIB recycling faces two persistent challenges: non-recyclable reductants in organic acid systems and inefficiencies in processing mixed cathode powders. Herein, we introduce a closed-loop methanol-sulfosalicylic acid (MeOH-SSA) system for rapid, sustainable metal recovery. Leveraging microwave-assisted leaching, this approach achieves exceptional efficiencies (>99 % within 15 min) for extracting Li, Ni, Co, and Mn, governed by an internal diffusion-controlled mechanism with notably low activation energies (15.39, 17.57, and 17.55 kJ mol for Ni, Co, and Mn, respectively). Our integrated recovery process, encompassing oxalate coprecipitation, MeOH regeneration, and LiPO isolation, achieves complete recovery of Ni and Co, high recovery of Mn (97 %), and effective Li recovery (95.87 % with 94 % purity), alongside 92.53 % MeOH reuse. A techno-economic analysis highlights significant advantages: a net profit of $22.59 per kg of processed cathode material with an energy consumption of 28.09 MJ kg, outperforming conventional methods in cost-efficiency and environmental footprint. Notably, this system excels across both single-component and mixed cathode compositions. By simultaneously addressing reductant reusability and mixed-cathode compatibility, this work establishes a versatile, eco-efficient framework for LIB recycling.