Crosslinked, highly conductive binder unlocks low-temperature silicon anodes for lithium-ion batteries

Abstract

Silicon (Si) is a promising anode material for high-energy-density lithium-ion batteries, due to its ultrahigh theoretical specific capacity and suitable lithiation/delithiation potential. However, its ∼300% volume expansion during charge/discharge cycles severely destroys the structure integrity of the electrode, causing poor cycling stability. Developing functional binders represents a facile and effective strategy to address this challenge. Herein, a novel multifunctional binder with enhanced adhesion strength and mixed ionic–electronic conductivity is rationally designed by integrating poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and guar gum (GG). This binder forms robust interactions with Si particles through abundant hydrogen bonds, ensuring an exceptional mechanical adhesion. Meanwhile, ether–oxygen-rich GG boosts lithium-ion conductivity, while PEDOT enables fast electron transport, synergistically accelerating the electrode reaction kinetics. As a result, the Si electrode fabricated with this multifunctional conductive binder delivers excellent cycling stability (1539.6 mAh g⁻¹ at 1.0 A g⁻¹ after 400 cycles), outstanding temperature tolerance, and superior rate capability (1388.9 mAh g⁻¹ at a high current density of 5.0 A g⁻¹). The work proposes a novel approach for the design of a multifunctional binder targeting next-generation Si-based electrodes for high-energy-density lithium-ion batteries.