By hydrothermal synthesis method and orthogonal experiment design

graphene/metal oxide composite electrode materials were prepared from different metal oxides and graphene oxides under different experimental conditions. Moreover

galvanostatic charge-discharge test and AC impedance test were carried out for the composite materials. Then

the obtained electrochemical data was fitted by Origin software. The specific capacitance of the electrodes and the slope of low frequency line in Nyquist diagram were selected as the experimental evaluation indexes. Through comparative analysis of the best data of the two experimental indexes

the optimum synthesized conditions of graphene composites were selected as follows. Metal oxide: MnO2

mass ratio of metal oxide to graphene oxide: 1:1

hydrothermal temperature: 160 °C

hydrothermal time: 10 h. This study provides a reference path for preparation of graphene/metal oxide composite electrode materials by hydrothermal method.