F-Free Binders for Lithium-Ion Battery Cathodes: Structural Insights and Challenges

초록

The conventional cathode binder, poly(vinylidene fluoride) (PVDF), suffers from inherently weak interfacial adhesion due to its nonpolar molecular structure, resulting in nonuniform formation of the cathode-electrolyte interphase. Moreover, PVDF's strong carbon-fluorine bonds classify it as an environmentally persistent per- and polyfluoroalkyl substance, raising serious global environmental concerns and regulatory pressures. This review provides a comprehensive examination of representative fluorine-free (F-free) cathode binders-including poly(acrylic acid), polyimide, polysiloxane, polysaccharide-based polymers and segmented block copolymers-systematically emphasizing their structural features and electrochemical performance. To the best of our knowledge, this is the first detailed analysis specifically focused on the structure-function relationships of F-free binders for lithium-ion battery cathodes. Additionally, we discuss future research directions, underscoring the crucial need for developing cost-effective, environmentally benign F-free cathode binders optimized for solvent-free dry-electrode processing technologies.

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