Simultaneous electrochemical preparation and reduction of graphene with low oxygen content and its electrochemical prope
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Simultaneous electrochemical preparation and reduction of graphene with low oxygen content and its electrochemical properties for highperformance supercapacitors Guoxiang Xin1,2 · Yao Zhai1 · Bangwen Zhang1 · Jinling Song1 · Jinhui Zhang3 · Yanhui Wang2 · Jianbing Zang2 Received: 18 February 2020 / Accepted: 8 July 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Graphene with low oxygen content via an electrochemically anode exfoliation is desired. Here, an electrochemical exfoliation method to realize the simultaneous electrochemical preparation and reduction of graphene with low oxygen content is proposed using a flexible graphite sheet (FGS). Under water bath, the FGS is soaked into a NaBH4 solution under an electric field of 3 V/cm for 3, 9, 15 or 21 h (Gr-3/Gr-9/Gr-15/Gr-21). The C/O ratios of the FGS, Gr-3, Gr-9, Gr-15 and Gr-21 increase in turn by the X-ray photoelectron spectroscopy. The comparison between the electrochemical properties of the FGS, Gr-3, Gr-9, Gr-15 and Gr-21 indicates that the Gr-15 possesses a specific capacitance of 181 F/g and capacitance retention of 93.8% over 3000 cycles, which shows better electrochemical performances than the FGS, Gr-3, Gr-9 and Gr-21. The symmetric supercapacitor based on the Gr-15 achieves an energy density as high as 22.56 Wh/kg at a power density of 0.85 kW/kg.
1 Introduction Graphene, which possesses outstanding electrical, thermal, optical and mechanical performances as well as a large specific surface area [1–4], has been intensively researched in recent years since it was first exfoliated from graphite using scotch tape [5]. Since then, a number of methods have been reported for producing graphene, such as mechanical Electronic supplementary material The online version of this article (doi:https://doi.org/10.1007/s10854-020-03967-7) contains supplementary material, which is available to authorized users. * Guoxiang Xin [email protected] * Yanhui Wang [email protected] 1
School of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Baotou 014010, People’s Republic of China
2
State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, 066004 Qinhuangdao, People’s Republic of China
3
Department of Environmental and Chemical Engineering, Tangshan University, Tangshan 063000, People’s Republic of China
exfoliation [6], chemical reduction [7], chemical vapor deposition [8] and epitaxial growth [9]. As a method to prepare graphene, the electrochemical exfoliation of graphite garnered tremendous attention due to its desirable merits containing simple operation, high yield, low cost, and environmental friendliness [10–12]. The electrochemical exfoliation method is categorized into cathodic exfoliation and anodic exfoliation, according to the different types of potentials applied: positive or negative bias. The cathodic exfoliation may improve the integrity of graphene by protecting the graphit
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