Polypyrrole (PPy) decorated on reduced graphene oxide (rGO) films is successfully prepared with pyrrole (Py) monomers and rGO through one-step combining oxidation with polymerization reaction. Compared with the pure individual components, rGO/PPy compound turns out better electrochemical characteristics owing to the introduction of rGO sheets, which improves the specific surface area and the conductivity of composite material. When the amount of rGO is 10% of the total, the rGO/PPy compound delivers the best capacitance of 389.3 F g−1 at 1.0 A g−1 in a three-electrode system and 266.8 F g−1 at 0.25 A g−1 in the symmetric supercapacitor system. In addition, asymmetric device (rGO/PPy//AC) has been successfully fabricated using optimized rGO/PPy compound as positive electrode, activated carbon as negative electrode (AC) and 1 M Na2SO4 aqueous solution as electrolyte. The device obtains long cycle stability under the high-voltage region from 0 to 1.6 V, meanwhile displaying the satisfied energy density of 19.7 Wh kg−1 at 478.1 W kg−1. Besides, the rGO/PPy//AC device presents satisfactory rate capability and long life time.

    Abstract
    1 Introduction
    2 Experimental procedure
        2.1 Materials
        2.2 Preparation of reduced graphene oxide and rGOPPy compound
        2.3 Assemble about supercapacitor
        2.4 Characterization
    3 Results and discussion
        3.1 Characterization of materials
        3.2 Electrochemical measurements
        3.3 The performance of asymmetric supercapacitor
    4 Conclusions
    Acknowledgements 
    References

• Guijing Liu(School of Chemistry and Materials Science, Ludong University, Engineering Research Center of Environment‑Friendly Functional Materials, Ministry of Education, College of Materials Science and Engineering, Huaqiao University)
• Yanying Shi(School of Chemistry and Materials Science, Ludong University)
• Lei Wang(MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology)
• Yadong Song(School of Chemistry and Materials Science, Ludong University)
• Shanmin Gao(School of Chemistry and Materials Science, Ludong University)
• Dong Liu(School of Chemistry and Materials Science, Ludong University)
• Leqing Fan(Engineering Research Center of Environment‑Friendly Functional Materials, Ministry of Education, College of Materials Science and Engineering, Huaqiao University)