Free-standing graphene films prepared via foam film method for great capacitive flexible supercapacitors

摘要

Recently, graphene films have always attracted attention due to their excellent characteristics in energy storage. In this work, a novel graphene oxide (GO) film with excellent mechanical properties, whose thickness was regulated simply via changing the concentration of the surfactant, was successfully prepared by foam film method. After chemical reduction, the reduced GO (rGO) films have excellent electrical conductivity of similar to 172 S cm(-1). Moreover, the supercapacitors based on the rGO films exhibit satisfied capacitive performance of similar to 56 mF cm(-2) at 0.2 mA cm(-2) in 6 M KOH aqueous solution. Meanwhile, the flexible all solid state supercapacitors (FSSCs) based on the rGO films also show great volumetric capacitance of similar to 2810 mF cm(-3) at 12 mA cm(-3) (similar to 1607 mF cm(-3) at 613 mA cm(-3)) with polyvinyl alcohol-KOH gel electrolyte. Besides, after 10000 cycles and continuously bent to 180 degrees. for 300 times, the volumetric capacitance of the FSSC remains at 81.4% and 90.4% of its initial capacitance value, respectively. Therefore, the free-standing rGO films prepared via foam film method could be considered as promising electrode materials for high performance flexible supercapacitors. (C) 2017 Elsevier B.V. All rights reserved.