One-step construction of graphene-polypyrrole hydrogels and their superior electrochemical performance

Graphene-polypyrrole (GPPy) composites with 3-dimensional macrostructure were prepared by a one-step self-assembly process, in which the continuous oxidation-reduction reaction of pyrrole monomers and graphite oxide in the existence of Cu2+ finally resulted in the formation of macroporous hydrogels. The as-prepared hydrogel exhibited a high specific capacitance of 498 and 295 F g(-1) respectively at the scan rate of 5 mV s(-1) and the discharge current density of 1 A g(-1). Furthermore, a specific capacitance of 240 F g(-1) could be achieved even if at a high current density of 10 A g(-1), and maintained 80% of the capacitance value after charge-discharge for 5000 cycles. Such excellent capacitive properties in rate stability and cycling stability endow the GPPy hydrogels with great potential applications in high-performance energy storage devices. Besides, this study also provides new insights into the design and synthesis of graphene-based materials.