Reduced graphene oxide aerogel with high-rate supercapacitive performance in aqueous electrolytes
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NANO EXPRESS
Open Access
Reduced graphene oxide aerogel with high-rate supercapacitive performance in aqueous electrolytes Weijiang Si1†, Xiaozhong Wu1†, Jin Zhou1, Feifei Guo1, Shuping Zhuo1*, Hongyou Cui1 and Wei Xing2*
Abstract Reduced graphene oxide aerogel (RGOA) is synthesized successfully through a simultaneous self-assembly and reduction process using hypophosphorous acid and I2 as reductant. Nitrogen sorption analysis shows that the Brunauer-Emmett-Teller surface area of RGOA could reach as high as 830 m2 g−1, which is the largest value ever reported for graphene-based aerogels obtained through the simultaneous self-assembly and reduction strategy. The as-prepared RGOA is characterized by a variety of means such as scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. Electrochemical tests show that RGOA exhibits a high-rate supercapacitive performance in aqueous electrolytes. The specific capacitance of RGOA is calculated to be 211.8 and 278.6 F g−1 in KOH and H2SO4 electrolytes, respectively. The perfect supercapacitive performance of RGOA is ascribed to its three-dimensional structure and the existence of oxygen-containing groups. Keywords: Supercapacitor, Reduced graphene oxide aerogel, Current density, Cyclic voltammetry
Background As a novel energy storage device that bridges the gap between conventional capacitors and batteries, supercapacitor has attracted much attention for its high power density and long cyclic life [1]. The studies about supercapacitor mainly focus on the electrode materials such as transition metal oxides, conducting polymers, and particularly carbon materials that are perfect electrode materials because of their good conductivity, cyclic stability, and large specific surface area [2-4]. Carbon materials with different structures such as carbon nanotubes, carbon nanofibers, hierarchical porous carbons, and ordered mesoporous carbons are widely studied in recent years [5-8]. Apart from these carbon materials, graphene and graphene-based materials have also been widely studied as electrode materials of supercapacitor [9-13]. Graphene is a two-dimensional sheet of sp2-hybridized carbon, which possesses many remarkable properties such as high surface area, excellent mechanical strength, and low electrical resistivity [14,15]. However, * Correspondence: [email protected]; [email protected] † Equal contributors 1 School of Chemical Engineering, Shandong University of Technology, Zibo 255049, People’s Republic of China 2 School of Science, State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, People’s Republic of China
the practical preparation (chemical reduction process) of graphene-based material is often accompanied by the sacrifice of graphene surface area because the graphene layers are easy to restack through a π-π interaction during the chemical reduction process. In order to obtain graphene-based material with high specific surface area,
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