Free-standing reduced graphene oxide/polypyrrole films with enhanced electrochemical performance for flexible supercapacitors.

Abstract Flexible all-solid-state supercapacitors with specific energy higher than 1 mW h cm−3 after long-term cycles remain a hot research topic in energy storage systems. In this paper, free-standing reduced graphene oxide/polypyrrole films are produced at the ice/ethanol interface following by hydrogen iodide reduction. The reduced graphene oxide/polypyrrole films are featured with high specific surface area, three-dimensional porosity, and tunable thickness and electronic conductivity. The typical flexible all-solid-state supercapacitor based on reduced graphene oxide/polypyrrole films exhibits a high volumetric specific capacitance of 17.3 F cm−3 and a high specific energy of 2.40 mW h cm−3 with corresponding specific power of 136.1 mW cm−3 at a current density of 3 mA cm−2 (ca. 10 A g−1). After 10,000 cycles at 3 mA cm−2, the capacitance retention of the typical flexible supercapacitor retains 73.2%. The enhanced electrochemical properties of the flexible supercapacitors are attributed to the high specific surface area, three-dimensional porosity, and the synergistic effect between reduced graphene oxide and polypyrrole with respect to the composite films. Graphical abstract Image 1 Highlights • Free-standing rGO/PPy films are produced at the ice/ethanol interface. • rGO/PPy films have high specific surface area and three-dimensional porosity. • rGO/PPy-based flexible supercapacitors exhibit high volumetric specific capacitance. • rGO/PPy-based flexible supercapacitors exhibit high volumetric specific energy. [ABSTRACT FROM AUTHOR]