Preparation and characterisation of graphene oxide/ carbon nanotubes films

Three types of carbon nanotubes (CNTs) that were single-walled carbon nanotube (SWCNT), multi-walled carbon nanotubes (MWCNTs) and multi-walled carbon nanotubes with hydro xyl groups (MWCNTs-OH), were used to fabricate a series of graphene oxide (GO)/CNTs hybrid thin films by a simple solution casting method. The hybrid films showed excellent self-capacitance. The capacitance of the hybrid films was strongly dependent on the types of the CNTs and the size of GO/CNTs films. The hybrid films with MWCNTs or MWCNTs-OH incorporated showed significant high capacitance, compared with that of GO/SMCNT films. The maximal specific capacitance was 113.19 F/g observed in GO/ MWCNTs film with 83 wt% MWCNTs incorporated. The capacitance of the films was further elevated by altering the film sizes. The effects of the microstructure and film size on the electrical properties were assessed. Moreover, quantum effect was clearly observed in thick hybrid films. The origin of the quantum effect was revealed based on the analysis of the layer-by-layer structure of the hybrid films.