Functionalized Cellulose‐Based Binders for Lithium Cobalt Oxide Cathodes: Improving Stability and Lithium‐Ion Transport Under High Voltage

Lithium cobalt oxide (LCO) is a key material for high-energy-density lithium-ion batteries, but its application at high voltages is hindered by structural instability and interfacial side reactions. This study introduces a functionalized cellulose-based binder designed to address these challenges. By grafting polar groups onto cellulose, the material's crystallinity is reduced, solubility is improved, and strong adhesion with enhanced ion transport is achieved. The binder enables LCO cathodes to retain 95.9% of their capacity after 200 cycles at 4.6 V, significantly outperforming conventional polyvinylidene fluoride (PVDF) binders. Furthermore, the binder reduces polarization and facilitates lithium-ion diffusion, contributing to improved electrode stability and electrochemical performance. These results highlight the potential of functionalized cellulose-based binders as sustainable and effective solutions for stabilizing high-voltage LCO cathodes, paving the way for next-generation high-energy-density lithium-ion batteries.