Preparation and electrochemical performances of graphene/polypyrrole nanocomposite with anthraquinone-graphene oxide as active oxidant

A simple and facile method for graphene/polypyrrole nanocomposite (GPy) was developed using sodium anthraquinone-2-sulfonate monohydrate (AQS) and anthraquinone-2,6-disulfonic acid disodium salt (AQDS) as both the “oxidizing active agents” as well as “redox modifier”. The AQ(D)S modified graphene oxide(GO) played the role of “active oxidant” to in situ polymerize pyrrole and convert itself to AQ(D)S modified graphene synchronously at 70 °C. The analysis of Fourier transform infrared spectroscopy (FTIR), Raman, X-ray Diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) all confirmed the successful polymerization of polypyrrole and the elimination of the oxygen functional groups from GO. The bipolarons present in AQ(D)S-GPy and the high doping level proved by FTIR, Raman, electron spin resonance (ESR) and N1s of XPS analysis endowed the nanocomposite improved electrochemical performances. Specifically, AQ(D)S-GPy provided both higher specific capacitances (237 and 300 F/g) and better cycle stability than that of GPy, PPy or AQDS-Graphene. Moreover, working potential windows were enlarged to 1.5 V and 1.7 V due to the redox activity of the AQ(D)S. The symmetric supercapacitor based on AQDS-GPy exhibited high energy density (31.2 Wh kg−1 at a power density of 1.12 kW kg−1) and good cycling stability (86% capacitance retention after 2000 cycles).

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