Preparation of flexible and free-standing polypyrrole/graphene film electrodes for supercapacitors

Abstract

A flexible self-supporting and binder-free supercapacitor electrode is fabricated by embedding a polypyrrole (PPy) nanostructured network into only one side of a graphene thin film via a spin coating method and a subsequent hydrothermal process. Based on the amphiphilic nature of the graphene oxide (GO) thin film, the well-defined PPy nanoparticles are well dispersed and form a reticular structure on the thin film surface. After reduction treatment at a temperature of 180 °C, the reduced graphene oxide (rGO) thin film not only provides a large accessible surface area for the dispersion of PPy nanoparticles but also acts as a binder-free conductive current collector. The polypyrrole/graphene film (PGF) electrode material exhibits an excellent electrochemical performance in the three-electrode configuration, including a high specific capacitance of up to 455 F g⁻¹ at 1 A g⁻¹ and outstanding cycling stability (97% capacitance retention after 1000 cycles). In addition, the symmetric PGF supercapacitor shows a specific capacitance of up to 49.3 F g⁻¹ at a cell voltage of 1.4 V and exhibits a maximum energy density of 13.4 W h kg⁻¹ at a power density of 700 W kg⁻¹, with 96% capacitance retention after 1000 cycles. This work shows impressive potential in fabricating high-performance flexible electrodes for supercapacitors.