▎ 摘　　要

A facile and simple method to prepare tube-like nitrogen-doped graphene (NG)/manganese oxide (Mn3O4) composite is introduced. The transmission electron microscopy patterns show that the Mn3O4 nanotubes were uniformly dispersed on the surface of the NGs. The composite was further investigated by Raman spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The electrochemical properties of NG/Mn3O4 composites were tested by cyclic voltammetry curves and galvanostatic charge-discharge curves. The results of the electrochemical measurement show the high capacitance and good long-term stability of NG/Mn3O4 composites.