Role of Reduced Graphene Oxide Binder for Supercapacitor with Commercial-Level Mass Loading

Abstract

Effective specific-surface-area (SSA) utilization of active materials and rapid ion/electron transport within electrodes with commercial-level mass loadings (>10 mg cm−2) are critical for the practical applications of supercapacitors (SCs). In this study, we demonstrate a versatile method to achieve high-performance SCs for commercial applications using biomass-derived porous activated carbons (PACs) as the main active material and reduced graphene oxide (rGO) as a multifunctional conductive binder that holds the PACs in an interconnected-network structure across the entire electrode. In the resultant PAC–rGO, the rGO sheets not only effectively maintain the high SSA of the PACs to provide abundant active sites in contact with electrolyte ions but also provide conductive passages through which ions can easily pass to reach the PAC surfaces. Functional groups on the rGO binder also promote substantial ion-adsorption capability by improving electrolyte wettability. Benefiting from the multifunctional roles of the rGO binder, the obtained electrode exhibits outstanding specific and areal capacitances as well as excellent rate capability and cycling performance, even with a high mass loading of 12 mg cm−2, demonstrating its strong potential for use in high-performance SCs.