Study On Preparation And Electrochemical Properties Of Polyaniline/Graphene Composite Electrode Material

Polyaniline was constantly applied to prepare various composite materials owing to its high electrical conductivity. However, the bad cyclic property limited its development. Graphene has always been hotspots in the field of science research since it has been found. The two-dimensional crystal structure of graphene determined that it had features such as good conductivity and large ratio surface. The polyaniline was compound with graphene in this paper. Consequently, we not only ensured the conductivity of the composite material but also overcame the cycle stability of polyaniline at the same time. Meanwhile, the electric capacity of composite materials had also been greatly improved.Firstly, the graphene dispersion was prepared by electrolytic stripping method in this paper. And then Polyaniline/graphene composite was controlled made by cyclic voltammetry using quartz crystal microbalance. The composite was characterizated by scanning electron microscopy. The electrochemical performance was tested through cyclic voltammograms, constant current charge and discharge and electrochemical impedance. The specific content mainly includes the following aspects:(1) The preparation of graphene dispersion:with using graphite paper as raw material, using electrolytic stripping prepared graphene dispersion. This preparation process was simple. The products were mostly few-layer graphene rather than oxidized graphene. The stability of graphene dispersion was very well.(2) The constant potential adsorption of graphene:this paper also made some discussion on constant potential adsorption of graphene. The results demonstated that the graphene sheet could adsorb on the surface of gold electrode, with applied voltage of 0.8 V. The mass of the film was 0.46μg as the adsorption time was 2 h and the surface active agent was sodium dodecyl benzene sulfonate.(3) The layer by layer combination of polyaniline and graphene:using cyclic voltammetry scanning two circles prepared polyaniline layer and using the constant potential adsorption method made graphene layer. Cyclic voltammograms curves showed that the current plateau improved obviously after the adosorption of graphene, which reflected the contribution of graphene to composite material’s capacitance property.(4) Electrochemical Synthesis and characterization of Polyaniline/graphene composite films:according to certain proportion, mixing the prepared graphene dispersion with aniline monomer solution, polyaniline/graphene composite films were self-assembled by cyclic voltammograms. Changing the proportion between polyaniline and graphene and adding different surfactants, composite materials could obtain with different electrochemical properties. The results of scanning electron microscopy indicated that polyaniline spread over the surface of graphene sheets uniformly. The cyclic voltammograms test results suggested that when adding sodium dodecyl benzene sulfonate was surfactant, the cycle number was five, scanning potential range was in-0.1～1.0 V and the scanning speed was 10 mV-s-1, the mass of the firm at gold electrode was 4.66μg and the specific capacitance of the composite was 1738 F·g-1.When adding sodium 4-methylbenzenesulfonate was surfactant, the mass of the firm at gold electrode was 2.26μg and the specific capacitance of the composite was 1927 F·g-1 at the same condition.