Binder design strategies for cathode materials in advanced secondary batteries

As a type of device for the storage and stable supply of clean energy, secondary batteries have been widely studied, and one of their most important components is their cathode material. However, cathode materials are associated with challenges such as volume expansion, hydrogen fluoride corrosion, phase transitions and low conductivity. In addition to intrinsic modifications, binders demonstrate significant potential to enhance the electrochemical performance of cathodes. Nevertheless, despite their controllability, low cost and non-disruptive effect on the inherent structure of the active particles, there is a lack of comprehensive guidance on selecting and designing appropriate binders for cathode materials. Accordingly, this review comprehensively summarizes the cathode failure mechanism of various secondary battery systems including lithium-ion batteries, sodium-ion batteries, S-based batteries and other secondary battery systems. Based on this, the function and effect of binders are evaluated and the corresponding binder design strategies are analyzed and categorized into two classes of common issues and specific issues, providing a clear framework for designing novel binders for cathodes. Finally, crucial characteristics and prospects of advanced multifunctional cathode binders are discussed. This review can also guide attention toward the crucial role of binders in emerging battery systems and future potential systems.