Materials Chemistry and Physics, Vol.146, No.3, 446-451, 2014
Porous graphene gels: Preparation and its electrochemical properties
Ultra-light porous 3D network graphene oxide (GO) gels were prepared using a simple process of aqueous gel precursor freezing, solvent exchange, and ethanol drying rather than supercritical drying technology. The GO sheets were consolidated by cross-linked sodium alginate (SA) and the obtained GO-SA gel was reduced by glucose to prepare graphene nanosheet-SA (GN-SA) gel. The gels were characterized by FTIR, XRD, SEM, and nitrogen adsorption-desorption measurements. SA was proven to attach to GO or GN surfaces to form gels composed of macropores and mesopores. GO-SA gel exhibited a bulk density of 16.79 mg cm(-3), and adsorbed water 17.4 times, ethanol 20.5 times, and soybean oil 22.4 times the weight of GO-SA gel, while GN-SA gel exhibited a lower bulk density of 12.93 mg cm(-3), and adsorbed water 122 times, ethanol 16.9 times and soybean oil 323 times the weight of GN-SA gel. The electrochemical performance of the GN-SA gel was analyzed using cyclic voltammetry, electrochemical impedance spectrometry, and chronopotentiometry. The results revealed that GN-SA gel displayed superior capacitive performance with large capacitance (114.12 F g(-1)) and excellent cyclic performance. (C) 2014 Elsevier B.V. All rights reserved.