Boosting the electrochemical capacitive properties of polypyrrole

          We report a new dopant, carboxylated graphene oxide (GO–COOH), to boost the electrochemical capacitive properties of polypyrrole (PPy). Herein, PPy/GO–COOH composite electrodes are fabricated via a facile one-pot electrochemical polymerization in aqueous dispersion containing pyrrole monomers and GO–COOH, in which GO–COOH is obtained from GO through treatment with carboxylation. Electrochemical measurements indicate that PPy/GO–COOH composite electrodes possess markedly enhanced electrochemical capacitive properties as compared to PPy/GO composite electrodes. It is because that the GO–COOH, all-round carboxyl-covered nanosheets with edged and basal oxygen-containing sites, provides more active sites for PPy heterogeneous nucleation. In contrast, the nanosheets of GO only use the edged carboxyl groups. The as-prepared PPy/GO–COOH composite electrodes exhibit electrochemical capacitive properties with a high areal specific
capacitance of 170.9 mF cm-2 at 0.5 mA cm-2, superior rate capability, as well as cycling stability (retaining 96.9% of initial capacitance for 5000 cycles). This work is anticipated to stimulate further research interest for GO–COOH based composite electrodes in electrochemical energy storage applications.