Synthesis of polypyrrole wrapped graphene hydrogels composites as supercapacitor electrodes

Highlight
• Synthesis of pyrrole on the 3D framework of graphene hydrogel was performed.
• The hydrogel has the advantages of pseudo-capacitance of polypyrrole and the double layer capacitance of graphene.
• The hydrogel exhibits large specific capacitance, good rate capability and cycle stability.

Different mass ratios of polypyrrole (PPy) to graphene hydrogel (GH) nanocomposites were synthesized by hydrothermal reduction of graphene oxide and chemically oxidative polymerization of pyrrole, forming a three-dimensional framework of PPy wrapped on the surface of GH without adding any toxic reductive agents. Electrochemical tests show that PPy/GH15 nanocomposite exhibits unique electrochemcial properties, such as enhanced electrolytic permeability and high electric capacity. Thanks to the synergistic effect of the pseudo-capacitance of PPy and the electric double layer capacitance of GH, PPy/GH15 exhibits a high specific capacitance of 375 F g−1 at a scan rate of 10 mV s−1. In addition, the PPy/GH15 electrode shows good cycling stability, and its specific capacitance retention is 87% even after 4000 charge–discharge cycles in the potential window of −0.1 to 0.6 V, suggesting it an ideal electrode material for supercapacitor.