Objective:
The direct recycling of lithium iron phosphate (LFP) cathodes from both production scrap (PScr) and end-of-life (EoL) cells is essential to reducing the environmental impact of lithium-ion batteries (LiBs) and reclaiming valuable materials for reuse in the battery lifecycle.[1,2] This study evaluates an aqueous delamination approach for direct recycling of LFP cathodes with different binders—CMC/SBR and PVDF—and examines how factors such as the state of charge (SoC) and electrolyte variations of EoL influence delamination behavior and recycling potential.

Methods:
LFP cathodes from PScr and EoL cells were subjected to an aqueous delamination process. The resulting materials were analyzed using SEM, XRD, and various electrochemical techniques to determine any potential damage from delamination. Different solvents, selected for their polarity and molecular size, were applied to investigate binding interactions between cathode material, binders, and the current collector.

Results:
Water proved to be a highly effective delamination agent for both CMC/SBR and PVDF binder systems. Elevated temperatures enable processing times of under a minute. Analytical results shed light on possible damage to the active materials, suggesting that this method maintains the material’s integrity for reuse. Delamination efficiency varied significantly with factors such as electrolyte composition and SoC in EoL cells, while solvent temperature and pH were key parameter influencing processing time.

Discussion:
Aqueous delamination offers a sustainable approach to LFP cathode recycling, especially for cathodes using CMC/SBR binders, potentially supporting an economic and environmentally friendly recycling process. Nonetheless, the binding mechanisms require further understanding to extend this approach to other cathode systems. SoC and electrolyte composition should be considered when designing cathodes optimized for future recycling. Overall, this work supports sustainable recycling methods for LFP cathodes, contributing to the circular economy in battery manufacturing.

[1] J. Dunn, M. Slattery, A. Kendall, H. Ambrose, S. Shen, Environ. Sci. Technol. 2021, 55, 5189.
[2] A. Wolf, F. Nagler, P. Daubinger, C. Neef, K. Mandel, A. Flegler, G. A. Giffin, Energy Environ. Sci. 2024.