Understanding the Role of a Water-Soluble Catechol-Functionalized Binder for Silicon Anodes by Diverse In Situ Analyses

Traditional binders generally interact with silicon particles via weak van der Waals forces and consequently lackinteractions between active materials after volume expansion.Water-soluble binders have recently garnered lots of attention aslow-cost and environmentally benign aqueous media to overcomethe main challenges with practical processing considerations.Herein, we report the development of a multifunctional polymericbinder having a three-dimensional network structure for silicon-based anodes, providing three advantages over traditional binders:greater structural integrity against expansion, stronger adhesion toanode components, and higher ionic conductivity. Diverseoperando observations clearly show that the novel multifunctional binder mitigates the microstructural changes of siliconat nanoscale and microscale levels compared to conventional linear binders, resulting in a high electrochemical performance ofapproximately 1100 mAh g-1even after 1000 cycles. Our systematic study on the effects of this multifunctional binder will beof great help in the rational design of polymer binders for advanced batteries