Striking a Balance: Exploring Optimal Functionalities and Composition of Highly Adhesive and Dispersing Binders for High‐Nickel Cathodes in Lithium‐Ion Batteries

Abstract Nickel‐rich layered oxide, LiNi x Co y Mn z O 2 (NCM, x > 0.8), has emerged as a promising cathode material for lithium‐ion batteries due to its high specific capacity and energy density. However, there remains a challenge regarding NCM degradation during cycling, associated with interfacial side reactions and microcrack formation. Herein, a functional poly(norbornene‐ co ‐norbornene dicarboxylic acid‐ co ‐heptafluorobutyl norbornene imide) (PNCI)‐based binder system is introduced, with controlled functionalities and monomer compositions, to preserve the structural integrity of NCM. The PNCI binder system incorporates three different norbornene‐derived monomers with distinct functionalities, allowing for multifunctionality, including electro‐chemo‐mechanical stability, strong adhesion, and dispersibility. By systematically adjusting the molar composition of the PNCI binders, the overall binder characteristics are fine‐tuned, optimizing the adhesion and dispersion of electrode components. The optimized PNCI binder, with desired adhesion strength, surface energy, and polarity, plays a crucial role in facilitating the formation of a uniform electrode structure with a high areal mass loading of NCM, ensuring long‐term cycling stability. This study highlights the significance of striking a balance between functionalities and composition in binder systems to achieve high‐performance NCM cathodes.