A Bioderived Dual-Dynamic Binder with Gradient Energy Dissipation Enabling Durable Silicon Anodes for Sustainable Lithium-Ion Batteries

The severe volume expansion of silicon (Si) anodes poses a critical challenge for high-energy-density lithium-ion batteries. Herein, we report a bioderived, dual-dynamic binder, PBT-c-PAEM, constructed by embedding a poly(acrylic acid-co-ethyl acrylate-co-acrylamide) (PAEM) terpolymer within a peach gum-borax-tannic acid network. This architecture integrates dynamic borate ester bonds with gradient hydrogen bonding, affording enhanced mechanical robustness and stable solid electrolyte interphase formation. Notably, the system offers unique compositional tunability, enabling a stress-matching strategy, in which the biomass fraction is tailored to the expansion stress associated with different Si contents. Consequently, the optimized Si@PBT-c-PAEM electrodes deliver an initial discharge capacity of 3450 mAh g–1 with an initial Coulombic efficiency of 90.5% and maintain 1823 mAh g–1 after 500 cycles at 2 A g–1. Multiscale mechanistic investigations confirm that this molecularly engineered network effectively dissipates stress and preserves the electrode integrity. This study presents a sustainable composition-adaptive design strategy for durable silicon-based anodes.