Supercritical CO2 processing to improve the electrochemical properties of graphene oxide

Porous graphene oxide (GO) structures at different oxidation levels have been obtained by a SC-CO2 assisted process performed at 200 bar, 35 degrees C and different durations up to 24 h. Supercritical CO2 processing was aimed at exfoliating and reducing graphene oxide. Different techniques were used to characterize the materials obtained: transmission electron microscopy (TEM), Raman and FT-IR Spectroscopy, X-ray diffraction analysis and N-2 adsorption desorption at 77 K. The materials with high surface area up to 930 m(2)/g, obtained after SC-CO2 treatment, exhibited unique mesoporous structure based on curve graphene sheets and a high capacitive performance with values of 253 F/g at 1 A/g and of 210 F/g at 16 A/g; moreover, a good long cycle stability in aqueous electrolytes (higher than 90% after 2 x 10(3) cycles) has been also obtained. SC-CO2 processing proved to be successful and simple to be realized, producing high performance materials, characterized by high specific surface areas and supercapacitive performances. (C) 2016 Elsevier B.V. All rights reserved.