Transformation of Freon to 3D graphene frameworks for high-rate supercapacitors with high capacity retention

Abstract

Transforming carbon-containing wastes into useful porous carbon materials is highly desired. The strategy can not only relieve environmental pollution but obtain porous carbon electrodes for energy storage devices. Herein we report an efficient method to transform the ozone-depleting gas of Freon (CCl3F) into 3D graphene (3DG) frameworks for supercapacitor electrode materials. The 3DG possesses self-supporting interconnected meso- and macropore channels supported by the multilayer graphene frameworks, which can be well kept in actual 3DG electrodes. This characteristic, together with high conductivity, enables 3DG supercapacitors to present high rate performance through the effective synergy between ion and electron transports, thus achieving the high capacitance retention of 76.1% (156 F g−1 at 100 A g−1) relative to the original capacitance (205 F g−1 at 1 A g−1), as well as high energy density retention (42.3% at 100 A g−1). The capacitance retention is much higher than that of typical reduced graphene oxide, and comparable to those of the reported state-of-the-art carbon-based materials. This study provides new strategy to dispose carbon-rich environmental pollutants for useful porous carbon electrode materials.