Preparation And Electrochemical Properties Of Polyaniline Composites

Supercapacitors, which are known as electrochemical capacitors. In comparison with traditional secondary battery, the supercapacitors exhibit faster and higher power capability, long life, wide thermal operating range and low maintenance cost. Nowadays, polyaniline is attracting more and more focus as a potential material for supercapacitors due to its facile synthesis, environmental stability and simple acid/base doping/dedoping chemistry. In this article, the different synthesis methods were prepared polyaniline/grapheme oxide/MnO2, polyaniline/graphene/MnO2, polyaniline carbon spheres, polyaniline/Fe3O4/SiO2/SnO2and so on composite material. The prepared composite material are applied in the electrochemical capacitors. The main results are as follows:First, we synthesis of polyaniline/graphene oxide hybrid material, and then treated with hot sodium hydroxide solution to obtain the reduced graphene oxide/poly aniline hybrid material. Finally, mixing the above hybrid materials with KMnO4, effect of KMnO4concentration on loading amount of MnO2on surfaces of polyaniline/graphene hybrid material is investigated. Polyaniline acted as both a carrier and a reducing agent for KMnO4in the composite. Products were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), X photoelectron spectroscopy (XPS) and ultraviolet-visible (UV-vis) spectra. Electrochemical studies show that the MnO2/polyaniline/graphene hybrid material has specific capacitance as high as704.3F/g at current density of0.2A/g and shows a good cyclability performance at a high rate.The carbon spheres were prepared from glucose under hydrothermal conditions. The degree of crystallinity can be improved by annealed in nitrogen (400℃,600℃,800℃). And then chemical oxidative polymerization of aniline in the presence of the carbon spheres yielded composite materials with a layer of polyaniline deposited on the external surface of the carbon spheres. Products were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and so on. The composite materials showed better electrochemical performance than the pure individual components, and with the increase of anneale temperature,electrochemical properties also be improved.First prepared the uniform Fe3O4magnetite microspheres by hydrothermal method. Due to incompatibility of Fe3O4,uniform Fe3O4magnetite microspheres were coated with a thin silica layer through a sol-gel approach to obtain nonporous silica Fe3O4composites(designated Fe3O4/SiO2). And then SnO2be deposited on the external surface of Fe3O4/SiO2through the hydrothermal method. Silica coating not only reduces the surface curvature but also modifies the surface properties, which are beneficial to subsequent hydrothermal deposition of polycrystalline SnO2forming uniform shells. Finally, chemical oxidative polymerization of aniline in the presence of the Fe3O4/SiO2SnO2yielded composite materials with a layer of polyaniline deposited on the external surface of the Fe3O4/SiO2/SnO2. Products were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and so on. The composite material can be applied in lithium-ion batteries.