▎ 摘　　要

Nanocomposites of well-standing delta-MnO2 nanoplatelets on nitrogen-doped reduced graphene oxide (delta-MnO2/NRGO) were synthesized via a simple hydrothermal method. Herein, p-phenylenediamine serves as the molecule for "anchoring" delta-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. delta-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 (24.2Wh 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. (C) 2019 Elsevier B.V. All rights reserved.