Spider web-inspired structural design for an energy-dissipating polymer binder enabling stabilized silicon anodes

Abstract

Silicon (Si) is considered one of the most promising anode materials for next-generation lithium-ion batteries due to its ultrahigh theoretical capacity. However, its application is significantly limited by severe volume expansion, leading to structural degradation and poor cycling stability. Polymer binders play a critical role in addressing these issues by providing mechanical stabilization. Inspired by the mechanically adaptive architecture of spider webs, where stiff radial threads and extensible spiral threads act in synergy, a dual-thread architecture polymer binder (PALT) with energy dissipation ability enabled by integrating rigid and flexible domains is designed. The rigid poly (acrylic acid lithium) (PAALi) segments offer structural reinforcement, while the soft segments (poly (lipoic acid-tannic acid), LT) introduce dynamic covalent bonds and multiple hydrogen bonds that function as reversible sacrificial bonds, enhancing energy dissipation during cycling. Comprehensive experimental and computational analyses demonstrate effectively reduced stress concentration, improved structural integrity, and stable electrochemical performance over prolonged cycling. The silicon anode incorporating the PALT binder exhibits a satisfying capacity loss per cycle of 0.042% during 350 charge/discharge cycles at 3580 mA g⁻¹. This work highlights a bioinspired binder design strategy that combines intrinsic rigidity with dynamic stress adaptability to advance the mechanical and electrochemical stability of silicon anodes.