Hydrothermal synthesis of well-standing δ-MnO2 nanoplatelets on nitrogen-doped reduced graphene oxide for high-performance supercapacitor

Nanocomposites of well-standing δ-MnO2 nanoplatelets on nitrogen-doped reduced graphene oxide (δ-MnO2/NRGO) were synthesized via a simple hydrothermal method. Herein, p-phenylenediamine serves as the molecule for “anchoring” δ-MnO2 on graphene oxide, as well as the nitrogen source. Especially, graphene oxide was functionalized with p-phenylenediamine firstly, which was used as the substrate for growing of uniform MnO2 nanostructures. δ-MnO2/NRGO nanocomposites were characterized by Scanning Electron Microscopy, Transmission Electron Microscopy, X-ray Diffraction, Fourier Transform Infrared Spectroscopy, and X-ray Photoelectron Spectroscopy. The electrochemical performance of the as-synthesized nanocomposites was investigated, which displayed excellent specific capacitance (299.5 F g−1 at 5 mV s−1), superior cycle stability (97.8% retention after 8000 cycles) and good energy density (24.2 Wh kg−1 with the power density at 242 W kg−1). The improvement is primarily attributed to the specific nanostructure, as well as the doping of nitrogen which provides more active sites and promotes charge transferring.