▎ 摘　　要

Supercapacitors have been caught great attention owing to their high power density and fast charge/discharge ability with superior capacitance retention which originates from the formation of an electrical double layer on high surface area electrodes. In this study, Two-step organic sol-gel procedure is applied to graphene oxide to produce high surface area nitrogen doped graphene samples varying in surface area and nitrogen content. The higher impacts of specific surface area and porosity on capacitative performance of graphene than nitrogen content are observed in different electrolytes. All the samples give superior capacitative performance than those of graphene oxide and blank sample, but higher in acidic electrolyte than the alkaline yielding a volumetric specific capacitance of similar to 118 F.cm(-3) with Coulombic efficiency of >99% and capacitance retention >80% after 10,000 successive cycle. Based on the weight of active material, the maximum gravimetric energy density is as high as 39 Wh.kg(-1) in acidic electrolyte at 0.1 A.g(-1), which is almost 2.6 times of graphene oxide used in this study. (C) 2020 Elsevier B.V. All rights reserved.