Functionalized Chitosan-based Polymer Binder in Silicon-carbon Negative Electrodes
Using chitosan as the foundation,we ingeniously introduced carboxyl groups to enhance its water solubility and further grafted phenylboronic acid groups with hydroxyl-terminated polydimethylsiloxane(PDMS-OH)for crosslinking,successfully fabricating a polymer binder with a three-dimensional network structure.This innovative design not only significantly improved the water solubility of the binder but also strengthened its interaction with active materials,resulting in higher stability during battery cycling.Additionally,the introduction of the flexible PDMS segment created efficient channels for lithium ion transport,while the boron element in the grafted phenylboronic acid groups facilitated the desolvation of lithium ions,further accelerating their transport.Consequently,this binder conferred exceptional lithium ion diffusion coefficients(both charge and discharge coefficients reaching 10-9.6)to the battery,enabling it to maintain outstanding specific capacity even at high current densities.This significantly enhanced the battery's rate performance and achieved a remarkable initial Coulombic efficiency of 96.27%.With its robust binding strength and high lithium ion diffusion coefficient,the binder prepared in this study exhibited excellent performance in silicon-carbon anodes,providing rapid and stable performance for batteries during high-rate cycling.Therefore,this CFPO binder undoubtedly stands out as an outstanding choice for silicon-carbon anodes.
Silicon/Graphiteboronic acidChitosanlithium ion diffusion coefficientwater soluble binder
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