Novel 3D graphene foam-polyaniline-carbon nanotubes supercapacitor prepared by electropolymerization

In this work, we present a novel supercapacitor (SC) material based on 3D graphene foam-polyaniline (Pani)-Carbon nanotubes (CNTs) composite for supercapacitor applications. Graphene foam was fabricated by chemical vapor deposition (CVD) on Ni foam using acetylene carbon source and hydrogen gas carrier at 700°C for 3 minutes. Next, the foam was etched in 3M HCl for an hour to remove most of Ni support. Multi-wall CNTs powder were then dispersed in 1M HCl and 0.2 M aniline monomer was then added, stirred and filtered to remove non-dispersed CNTs. Electro-polymerization in the CNTs-aniline monomer solution was then conducted at working electrode potential of 0.55 V vs. Ag/AgCl. SEM and Raman characteirzation confirmed the incorporation of CNTs in Pani/graphene foam network with a number of nanowire features appeared on graphene foam surface and dominant D and G carbon´s peaks. SC performances were then tested by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) measurements in 2M H₂SO₄ electrolyte. CV results showed that PANI´s redox peaks were broadened due to the presence of CNTs, indicating enhanced pseudocapacitance. From GCD measurements, it is found that CNTs-Pani-graphene foam exhibits a high specific capacitance of 920 Fg-1 at a specific current of 0.8 Ag-1, which is more than twice higher than that of Pani-graphene foam (430 Fg-1).