▎ 摘　　要

Colloidal Mn3O4 nanocrystals supported by graphene oxide (GO) and reduced graphene oxide (RGO) (Mn3O4/GO and Mn3O4/RGO nanocomposites) have been fabricated through a facile synthetic route with ultrasonic-assisted in ethanol amine (ETA)-water system. It is proposed that in the formation mechanism of these intriguing nanocomposites, investigated by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), ultraviolet-visible absorption spectroscopy (UV-vis), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, the manganese ions are anchored on GO nanosheets (GOs) or enwrapped in curved RGO nanosheets (RGOs), followed by the nucleation and growth of Mn3O4 nanoparticles in ethanol ETA-water system via hydrolysis and oxidation, which in turn results in the exfoliation of GOs or RGOs. Based on the surface properties of GO and RGO, this work firstly explains how the synergetic compositing structure of Mn3O4/GO and Mn3O4/RGO nanocomposites plays a very important role in their properties for electrochemical capacitors (ECs) or lithium ion batteries (LIBs). The opinions we put forward may be readily extended to a strong basis for other classes of hybrids based on GOs or RGOs to make a wise choice between the ECs and LIBs applications.