Effects of graphene reduction degree on capacitive performances of graphene/PANI composites

• The reduction of graphene oxide affected its surface chemistry, aggregation and conductivity.
• The use of reduced graphene oxide was successfully used for preparing RGO/PANI composites.
• The RGO/PANI composite exhibited high capacitances and good cycling stability.
• A proper load of PANI was required for high capacitances and good rate performance of the composite.

Reduced graphene oxide (RGO) was compounded with polyaniline (PANI) to prepare supercapacitor electrode materials. For the preparation, graphene oxide (GO) was reduced with glucose and ammonia, and then PANI was in situ deposited onto the RGO nano-sheets by polymerizing aniline with ammonium persulfate (APS) as oxidizing agent. The obtained composites were characterized with scanning electron microscope, Fourier transform infrared spectroscopy, Raman spectroscopy, UV–vis absorption spectroscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy (EIS). It was found that with increasing reduction time, the oxygen content on the surface of GO was decreased, leading to increased ID/IG ratio in the Raman spectra of GO and increased conductivity of GO. Consequently, the capacitance properties of RGO/PANI composites could be significantly improved by the reduction of GO. It was also observed that the initial concentrations of aniline being used for the polymerization could influence the rate performance of the composite. Under the optimal preparation conditions (the reduction time of graphene 60 min, the initial concentration of aniline 0.025 mol L−1, and the molar ratio of aniline to APS 1:1), the obtained composites exhibited a specific capacitance as high as 1045 F g−1, along with a retention of 97% after 1000 cycles.

The reduction of graphene oxide improved significantly the capacitance of RGO/PANI composites.Figure optionsDownload as PowerPoint slide