Preparation Of Polyaniline Doped By Modified Graphene And Their Electrochemical Properties

Supercapacitors, with the advantages of rapid charge/discharging rates, longcycle life, environmental friendliness and convenience; have raised enormousattention owing to their promising applications in energy field. They act assupplementary power sources for tranditional capacitors and batteries in electricvehicles and digital devices. In our study, polyaniline (PANI) based compositeelectrode materials were prepared to achieve property complementary. Finally highperformance electrodes were obtained based on the synergistic effect of individualcomponent.In this study, PANI was synthesized by cyclic voltammetric method, and theeffects of different parameters during the synthesis process, including theconcentration of aniline monomers and H2SO4, were studied. The grapheneoxide/polyaniline (GO/PANI) composite was prepared by the one-stepelectrochemical co-deposition method. The different mass concentrations of GO wereutilized to improve the electrochemical performances. The maximum specificcapacitance of the GO/PANI composite achieved1136.4F g-1with a GOconcentration of10mg L-1at a scan rate of1mV s-1, which is almost two-fold higherthan that of PANI (484.5F g-1). The GO/PANI composite also showed a good cyclingstability, retaining over89%of its initial capacitance after1000cycles. Highelectrochemical performances were attributed to increasing active sites for thedeposition of PANI provided by large surface areas of GO sheets and the synergisticeffect between GO and PANI, shortening the ion diffusion paths.Furthermore, the sulfonated graphene/polyaniline (SG/PANI) composites havebeen prepared via in-situ chemical polymerization doped by SG without protonatedthrough any other inorganic or organic acids. The sulfonate groups of SG are servedas the dopant for PANI. The maximum specific capacitance of the SG/PANIcomposites achieves676F g-1with the mass ratio of SG and aniline1:30at a currentdensity of0.1A g1. The SG/PANI composite also shows the advantage of goodcycling stability retaining over97%of its initial capacitance after1000cycles, andexcellent rate performance with74%capacitance retention from0.1A g1to10A g1,while PANI only keeps26%of initial capacitance. The SG/PANI composite withexcellent capacitor behaviors is supposed to be an excellent electrode material forcapacitors.