High-rate capacitive performance of graphene aerogel with a superhigh C/O molar ratio

Abstract

Graphene aerogel (GA) is successfully prepared through hydrogen reduction of graphene oxide aerogel (GOA) which is self-assembled from graphene oxide solution and subsequently dried by a supercritical CO 2 method. The morphology, structure and surface property evolution in the preparation of GA are investigated intensively by a variety of means such as atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), N 2 adsorption, X-ray diffraction (XRD), Raman spectroscopy, ultraviolet-visible absorption spectroscopy (UV-Vis), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). A self-assembly mechanism based on the hydrogen-bonding interactions between hydroxyl groups and carbonyl groups is proposed for the first time to explain the formation of GA. As evidenced by elemental analysis (EA) and electrochemical measurements, this three dimensional GA has an unprecedented high C/O molar ratio of 69.9, which contributes to the excellent high-rate performance of this material for supercapacitor applications.

Enhanced thermal-conductive and anti-dripping properties of polyamide composites by 3D graphene structures at low filler content

“…The GF were synthesized by the hydrothermal process. In this procedure, the GO sheets were partly reduced to RGO sheets, and at the same time, graphene hydrogel with robust porous structures were self-assembled by the overlapped RGO sheets due to their strong p-p interactions [26]. Subsequently, graphene hydrogel converted to GF with density of 13 mg cm À3 by freeze-drying method, present a high porosity, as high as $99% (Table S2).…”

Three dimensional nitrogen-doped graphene aerogels functionalized with melamine for multifunctional applications in supercapacitors and adsorption

“…Therefore, the relative high specific capacitance could be not only attributed to the double layer capacitance as result of the network or porous structures, but also the pseudo-capacitance of unreduced hydroquinone/quinone groups or carboxyl groups and high graphitic N content introduced into graphene. Furthermore, the O-rich surface also increased the hydrophilicity and polarity of NGAs and thus facilitate the wettability between the electrolyte 16 and network surface.…”

“…As a single layer of carbon atoms tightly packed into a two-dimensional (2D) sheet of sp 2 -hybridized carbon, graphene has attracted a great deal of attention in recent years because of its excellent strong mechanical [1,2], high electrical and thermal properties [3][4][5], and large surface area [6,7], which offering great opportunities for potential applications such as batteries [8][9][10][11][12][13], supercapacitors [14][15][16][17], fuel cells [18][19][20][21][22][23], photovoltaic devices [24][25][26][27], photocatalysis [28][29][30][31] and so on. However, due to noncovalent interactions such as π-π stacking and hydrophobic interactions [32,33], the obtained 2D graphene tend to interact with each other to form irreversible aggregates or overlap into graphitic structure between the intersheet of graphene, resulting in a dramatic decrease of the surface area [34].…”

Significant role of ultramicropores on capacitive properties of polypyrrole-based carbons

“…Carbon-based materials, possessing the merits of high electrical conductivity, low-cost, environmental friendly and chemical stability, have been widely studied in the energy-related fields especially in supercapacitor [1][2][3][4][5]. The energy storage mechanisms for carbon-based supercapacitor include electrical double layer (EDL) capacitance generated from the charge separation on the electrode/electrolyte interface and extra pseudocapacitance introduced by some heteroatom functionalities.…”