Porous graphene gels: Preparation and its electrochemical properties

Abstract

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 12.2 times, ethanol 16.9 times and soybean oil 32.3 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.