Synthesis of a Graphene-Polypyrrole Nanotube Composite and Its Application in Supercapacitor Electrode

A novel composite was obtained by hybridizing polypyrrole (PPY) nanotubes with chemically reduced graphene sheets, which comprehensively utilizes the advantages of electric double layer (EDL) capacitor and pseudo-capacitor. Scanning electron microscopy and transmission electron microscopy images revealed that graphene sheets in the graphene-polypyrrole (GP) composite obtained intimately interacted with PPY nanotubes. Raman and UV-vis spectra of the GP composite were measured and a solid interaction between graphene and PPY was observed. The electrochemical performance of the GP composite was evaluated and a specific capacitance of 400 F/g at a current density of 0.3 A/g was obtained; this capacitance is higher than that of a previously reported graphene-polypyrrole nanofiber composite. Furthermore, at a current density of 1.5 A/g, the specific capacitance of the GP composite fabricated in this work is as high as 324 F/g, suggesting its possible application in supercapacitors.