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Supercapacitor, also called electrochemical capacitor, is an ideal device for electric energy storage and usage.Charge storage ability of supercapacitor is mainly limited by the kind of materials.Graphene, which possesses outstanding electron conductivity and immense specific surface area (2630 m2/g, theoretical value),has the great potential application in supercapacitor[1,2].However, Van der Waals force between graphene sheets causes graphene easy to agglomerate, resulting significant decrease in specific surface area and specific capacitance[3].In this study, the three-dimensional graphene hydrogel was synthesized first by hydrothermally treating the graphene oxide(GO) colloidal suspensions with varied concentration (2, 5 and 10 mg/ml) and then freeze-dried to produce three-dimensional graphene aerogel (noted as GAG).The GAG were characterized by SEM, FT-IR, XRD, Raman, and N2 adsorption-desorption.The BET specific surface area, porosity and pore distribution of GAG were influenced by the concentration of precursor graphene oxide suspension.The chemical capacitance of GAG was evaluated in 6M potassium hydroxide using a three-electrode system.The specific capacitance of GAG made from 2, 5, 10 mg/mL GO suspension(labeled as 2GAG, 5GAG and 10GAG respectively) at scan rate of 10 mV/s is 94 F/g, 165 F/g and 149 F/g respectively.For comparison, the specific capacitance of activated carbon in the same case was only 114 F/g.The 5GAG achieved the highest specific capacitance owing to the rational surface aera and pore distribution.The specific capacitance of GAG decrease gradually along with the increasing of the scan rate, and the 10GAG has the best rate capability.