Conductive Binder Integrated with Hydrogen Bonding and Coulombic Interactions Enables Self-Healing and Robust Silicon Anodes

Abstract

The poor conductivity and severe volume effect of silicon anodes lead to sluggish lithiation/delithiation kinetics and electrode pulverization, largely impeding the cyclability of the batteries. A multifunctional binder system that can simultaneously address these issues is highly demanded. Herein, we report a conductive interpenetrating gel network (marked as CGP) constructed by cationic guar gum and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) through dynamic H-bonds and Coulombic interactions, which further donates self-healing capability to accommodate volume expansion. The lone-pair electrons of the oxygen and sulfur heteroatoms abundant in CGP coordinate with Li⁺ to optimize ion diffusion, while the conductive PEDOT:PSS facilitates electron transport, together achieving stable solid electrolyte interphases and enhanced reaction kinetics. Consequently, the Si@CGP electrode delivers a high initial discharge capacity of 3997.8 mAh g^–1 at 0.5 A g^–1 with a Coulombic efficiency of 84.1% and retains a reversible capacity of 1973.8 mAh g^–1 after 100 cycles. Notably, it still retains a high capacity of 1428.4 mAh g^–1 at 4.0 A g^–1, indicating its excellent cyclability and rate performance. The design of a conductive, self-healing binder may broaden the way toward efficient binder systems for high-performance silicon anodes.