A novel two-dimensional binder based on functionalized-graphene oxide for high performance Si anodes of Li ion batteries

To break through the variety limitation on active sites as well as molecular configuration of conventional polymeric chains, a novel two-dimensional binder is proposed to support Si anode via modifying oxidized graphene by p-aminobenzenesulfonic acid. Based on its flexible 2D structure, with the assistance of citric acid as the additive, this functionalized graphene oxide exhibits strong binding effect to anchor Si particles through strong and enriched point-to-plane interactions, which therefore effectively help maintain a pliable and robust 3D structure for the electrode when suffering from severe Si volume effect. Moreover, this binder introduces multiple Li ion transport paths by its sulfonated groups and defects etched on GO layers, so that can remarkably promote the Li⁺ diffusion rate in the electrode. Benefiting from this novel binder, the Si anodes demonstrate a high capacity of 1590 mAh g⁻¹ after 400 cycles under the current density of 1 A g⁻¹. The Li ion diffusion rate increases around one order of magnitude after the sulfonated functionalization of the binder. To sum up, this work verifies noticeable advantages of the GO-based binder on its flexible structure, enriched chemical properties and multi-functionalized potential, revealing a promising prospective of this two-dimensional binder on high performance Si anode applications.