Solvent and HF-free removal of polyvinylidene fluoride binder from spent lithium-ion battery cathode materials via attrition milling and liquid–liquid particle separation

Document Type

Article

Publication Date

8-30-2026

Department

Department of Chemical Engineering

Abstract

Direct recycling of lithium-ion battery cathode is hindered by the difficulty of removing polyvinylidene fluoride (PVDF) binder from cathode active materials (CAMs). Conventional methods, such as pyrolysis and solvent washing, generate hazardous gas emissions and secondary waste. In this study, we developed a solvent-free, toxic-gas-free process to liberate and separate PVDF from CAMs using mechanical and physical separation methods. Attrition milling effectively liberated PVDF from cathode particles, followed by liquid-liquid separation to recover high-purity CAMs. Under optimal conditions, the process produced a concentrate containing 99.5 wt.% CAM at a 97.2% recovery yield. Compared with conventional froth flotation, liquid-liquid separation achieves superior performance due to the enhanced hydrophobicity of PVDF in the oil phase and improved particle-droplet attachment efficiency. The recovered PVDF can be further purified by acid washing for potential reuse, while the recovered CAMs retains their original morphology and particle size, making them suitable for direct regeneration into new battery cathodes. These results highlight that liquid-liquid separation as a promising technique for producing high-purity CAMs and advancing direct lithium-ion battery recycling.

Publication Title

Resources Conservation and Recycling

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