Resilient binder network with enhanced ionic conductivity for High-Areal-Capacity Si-based anodes in Lithium-Ion batteries

Abstract

Silicon (Si) anode is a promising candidate for increasing the energy density of lithium-ion batteries (LIBs) owing to its high theoretical capacity (4200 mAh g-1) and low reaction potential (<0.4 V, Li/Li+). Unfortunately, the repeated volume changes of Si during charge/discharge cycles pose a critical challenge for its practical applications. Herein, a resilient binder network with enhanced ionic conductivity is reported to effectively integrate Si-based anodes. The highly stretchable polymer network on Si anodes enables the accommodation of external stress and recovers the damage through fast self-healing properties. In addition, the lithium sulfonate moiety of the polymer facilitates lithium-ion conduction within the binder network. Such an unprecedented binder network exhibits outstanding electrochemical performance in Si-based anodes. The exceptional physicochemical properties of the binder enable the fabrication of an ultra-thick SiOx/Gr electrode with a high mass loading of up to ≈ 19.1 mg cm−2 (≈ 14.3 mAh cm−2) while maintaining stable cycling. This work provides a novel pathway toward achieving high-areal-capacity and long-cycling Si-based anodes for developing high-energy–density batteries.