Continuous hierarchical carbon nanotube/reduced graphene oxide hybrid films for supercapacitors

Abstract

3D hierarchical carbon nanotube/reduced graphene oxide (CNT/rGO) hybrid films of enhanced electrochemical performance are obtained, by dispersing graphene oxide (GO) sheets into ethanol carbon source, ferrocene as catalyst and thiophene as promoter, the hybrid films are fabricated in novel direct injection floating catalyst chemical vapor deposition (CVD) method. With the addition of the rGO sheets, the hybrid films with enhanced surface area still retain the connecting structures of CNT networks. The resulting CNT/rGO films exhibit high specific capacitances of 151F/g in 2M KOH aqueous solution and 80F/g in 1M Na2SO4 aqueous solution under the scan rate of 5mV/s, respectively. The hybrid films with low content of rGO sheets receive more than triple specific capacitances as compensation for the pure CNT films. In addition, the capacitance retention of 97% after 5000 cycles demonstrates an excellent cycling property. These results indicate a promising material for scalable products to capacitive applications.