Ultrastrong Single-Walled Carbon Nanotubes/Graphene Oxide Nanosheets Hybrid Network Films as Flexible Electrode for Energy Storage

Homogeneous free-standing SWCNT/GO hybrid network films were fabricated using vacuum filtration method and their performances to be used as flexible electrodes in electrochemical capacitors were studied. Firstly, the SWCNT/GO hybrid films were treated under different temperature to investigate the influence of oxygen-containing groups on GO nanosheets on capacitive performance of them. Our results showed that the content of oxygen-containing groups had great influence on the capacitive performance of SWCNT/GO hybrid films and that the film annealed at 250 degrees C under 5% H2/Ar flow displayed an optimal capacitive performance. For the film with SWCNT/GO mass ratio of 1:4, specific capacitances of 171.85, 162.9, 148.98, 133.8, 112.8 and 82.24 F/g corresponding to discharge current of 5, 10, 20, 40, 80 and 160 A/g, respectively, were achieved. Secondly, the influence of mass ratio of SWCNT/GO on capacitive performance of SWCNT/GO hybrid films was also demonstrated. The hybrid films exhibited extremely high mechanical strength with tensile strength up to 461 MPa and specific capacitance of 105.2 F/g at current density of 5 A/g in case of 1:1 mass ratio of SWCNT/GO. A higher specific capacitance of 206.7 F/s at discharge current of 5A/g was obtained for the films with SWCNT/GO mass ratio of 1:8. Our SWCNT/GO hybrid network films showed good flexibility and durability over 2000 bending cycles test, indicating the potential to be used in flexible energy-storage devices.