Electrochemical in situ polymerization of reduced graphene oxide/polypyrrole composite with high power density

We demonstrate a novel method of in situ galvanostatic polymerization to prepare reduced graphene oxide (RGO)/polypyrrole composite (RGO-PPy) for supercapacitors electrode. The PPy and the RGO interact closely and form the composite with porous structure. The BET specific surface area of RGO-PPy reaches 108 m2 g−1. The RGO-PPy composites show the high protonation level on polypyrrole (PPy) ring (41.1%), which can be related to the doping of PPy by oxygen-containing groups in RGO sheet. The RGO-PPy electrodes exhibit good electrochemical performance. The specific capacitance of RGO-PPy electrodes still reaches 224 F g−1 at charge/discharge current density of 240 A g−1 within an electrochemical windows of 0.8 V in 3 M KCl aqueous solution. The specific power of RGO-PPy electrodes reaches 38.6 kW kg−1 when its specific energy reaches 2.5 Wh kg−1 in two-electrode cell. The RGO-PPy electrodes have good cycle stability and show less than 17% specific capacitance decay at a charge/discharge current of 30 A g−1 within an electrochemical windows of 0.8 V after 5000 cycles.