Screen-Printable and Flexible RuO2 Nanoparticle-Decorated PEDOT:PSS/Graphene Nanocomposite with Enhanced Electrical and Electrochemical Performances for High-Capacity Supercapacitor.

This work describes a ternary screen-printed electrode system, composed of aqueous poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonic acid) ( PEDOT: PSS), graphene, and hydrous ruthenium(IV) oxide (RuO2) nanoparticles for use in high-performance electrochemical capacitors. As a polymeric binder, PSS allows stable dispersion of graphene and hydrous RuO2 nanoparticles (NPs) in an aqueous PEDOT: PSS system through electrostatic stabilization, ensuring better utilization of the three components. Additional PSS molecules were added to optimize the solution viscosity to obtain screen-printed electrodes. The effects of graphene and hydrous RuO2 NPs on the electrical and electrochemical properties of PEDOT: PSS were systematically investigated. The graphene sheets greatly enhanced the charge-transport properties, such as the doping level and conjugation length, through strong π-π stacking interactions with the PEDOT structure. The hydrous RuO2 NPs anchored to the PEDOT: PSS/graphene surfaces facilitated redox reactions with the surrounding electrolyte, and significantly enhanced the specific capacitance of the electrode materials. The resulting RuO2/PEDOT:PSS/graphene electrode with a thickness of ∼5 μm exhibited high conductivity (1570 S cm(-1)), a large specific capacitance (820 F g(-1)), and good cycling stability (81.5% after 1000 cycles).