Honeycomb graphene–polyaniline nanocomposites as novel electrode materials for high-performance supercapacitors

Honeycomb graphene–polyaniline (HG–PANI) nanocomposites are synthesized through a facile electrostatic self-assembly approach, and the obtained material is characterized as the electrode for supercapacitor applications. HG–PANI comprises of fibrous polyaniline embedded within honeycomb graphene nanosheets, preventing the stacking of nanosheets and suppressing the volume expansion of polyaniline. In the nanocomposite, nitrogen (≈8 at%) exists in the form of quinonimine (N–), amine (–NH–) and positively charged nitrogen cation radical (N+), and the latter effectively enhances both the electronic conductivity of graphene and the surface activity of the electrode improving the capacitive performance of the nanocomposite. HG–PANI exhibits a mesoporous structure with an average pore size of 3.78 nm and a specific surface area of 40 m2 g−1 providing sufficient channels for the ion transport. The electrical conductivity of HG–PANI (80%) was measured to be 6289.31 S m−1, a 10-fold increase in electrical conductivity over the unmodified material HG. The specific capacitance of the material is measured to be 736.2 F g−1 at a current density of 0.5 A g−1, 81.6% higher than that of HG without the involvement of PANI. This article reports on the simple, scalable and low-cost preparation of a honeycomb graphene–polyaniline nanocomposite, and its supercapacitor application.