Preparation of sulfonated graphene/polyaniline composites in neutral solution for high-performance supercapacitors

Sulfonated graphene/polyaniline (SG/PANI) composites have been prepared via in situ chemical polymerization doped by SG without the protonation through any other inorganic or organic acids. The sulfonate groups of SG serve as the dopant for PANI. Scanning electron microscope and transmission electron microscope images show that the morphologies of the composites are controlled by varying the synthesis condition. Doping effect of SG, proved by ultraviolet absorption and X-ray diffraction spectra, is optimized by tuning the mass ratios of SG to aniline monomers to improve the electrochemical performance of SG/PANI composites. The maximum specific capacitance of the SG/PANI composites achieves 676 F g−1 with a mass ratio of SG to aniline 1:30 at a current density of 0.1 A g−1. The SG/PANI composite also shows a good cycling stability retaining over 97 % of its initial capacitance after 1,000 cycles, and the excellent rate performance with 74 % capacitance retention from 0.1 to 10 A g−1. The SG/PANI composite with excellent capacitor behaviors can be developed to be an excellent electrode material for high-performance supercapacitors.