Controlled Formation And Electrochemical Performance Of Graphene/Polyaniline Hybrids

Graphene and polyaniline (PANI) can be used as electrode materials of supercapacitors due to their unique physical and chemical properties. However the low specific capacitance and natural agglomeration of graphene nanosheets limit its applications. Individual PANI is also restricted because of the poor cycling life. In this thesis, the graphene/Polyaniline (GEP) hybrid electrode materials with high performance have been successfully fabricated. The hybrids were tested by Transmission Electron Microscope (TEM), Field Emission Scanning Electron Microscope (FE-SEM), X Ray Diffraction (XRD), Raman spectrum, FT-Infrared (FT-IR) Spectrum, electrical work station, Land battery system and 4-piont station. The main results are as follows:(1) The sandwich-like and nanowire-bridged hybrid materials of GEP were successfully fabricated with different proportion of isopropanol to water in solvent. The highest specific capacitance of hybrids obtained from the mixed electrolyte (1:1) could reach as high as 1350 F·g-1.It is a good candidate for supercapacitor electrode materials.(2) The hybrids with uniform morphology were synthesized in the mixed media (Visopropanol:Vwater=3:1) when the concentration of aniline was 0.125 mol·L-1. The specific capacitance of the obtained material was about 814 F·g-1, much higher than that of graphene (284 F·g-1) at the same conditions.(3) Various GEP materials were prepared from different precursors of graphene oxide with different degree of oxidation. Among of these, using graphene oxide from the mixed acids, the composite was bridged by PANI nanowires, and showed good performance of supercapacitance with the specific capacitance as high as 1150 F·g-1.(4) The GEP hybrids with different dopants of organic acids were controllably synthesized. The conductivity of the composite doped withβ-naphthalenesulfonic acid was as high as 7.1 S·cm-1. After 1000 charge/discharge cycles, the retention of the specific capacitance of this hybrid was still 65%, when the current density was 1 A·g-1.