Graphene-wrapped nitrogen-containing carbon spheres for electrochemical supercapacitor application

Graphene-wrapped nitrogen-containing carbon spheres (PLG) was fabricated by facile co-pyrolysis of graphene oxide (GO) and polyaniline-lignosulfonate (PL) composite at 800 °C, in which GO was regarded as skeleton, polyaniline was used as a nitrogen source, and lignosulfonate was served as a dispersant and morphology control agent of polyaniline. The nitrogen-containing carbon spheres obtained from PL precursor not only acted as spacers that prevent graphene nanosheets from aggregation, but also provided high specific surface area and channel for electrolyte ions to reach, playing an important role in improving the electrochemical properties of PLG composite. As supercapacitor electrodes, the graphene-wrapped carbon spheres structure of PLG exhibits a high specific capacitance and good cycling stability during repeating cyclic voltammetry measurement. A high specific capacitance of PLG is presented to be 266.7 F g−1 at a current density of 0.5 A g−1 and increased to 103.8% after 1000 cycles.