Preparation Of Graphene/polyaniline Composites And Their Applications In Supercapacitor Electrode Materials

Polyaniline is a widely used polymer material due to its excellent stability,unique optical,electrical,magnetic properties,etc.It has been widely used for many areas such as supercapacitors,batteries,sensors,electrochromic devices,and so on.On the other hand,graphene,as a new carboneous material,has gained a lot of attention due to its high conductivity,large specific surface area,and good environmental stability,etc.Graphene as well as graphene-based composites have been applied to energy storage,sensors,catalysis,and other fields.It should be noticed that methods of preparing graphene/polyaniline composite in reported literatures are complicated and capacitance of such materials were not very high.So,it is a still challenge to obtain a novel and simple method for preparation of graphene/polyaniline composite and simultaneously achieving high specific capacitance as well as good stability.There are five chapters in this dissertation.The first chapter gives an overview of the structure,doping and conductive mechanisms,synthetic methods and application of polyaniline.At the same time it also reports the structure,properties and preparation method of graphene,as well as knowledge of supercapacitor.In the second chapter,we synthesize polyaniline at varying concentrations of aniline monomer and electrolyte,different number of cycles and kind of electrolytes in order to gain higher capacitive performance.And we also character its electrochemical properties.In the third chapter,we use a novel and simple method for preparation of graphene/polyaniline composites through electropolymerization of aniline monomer in certain electrolyte containing graphene nanosheets.Additionally,we character polyaniline and graphene/polyaniline composites by the Fourier transformation infrared spectrum(FTIR),Ultraviolet-visible Spectroscopy(UV-vis),Raman Spectroscopy and Transmission Electron Microscopy(TEM).It shows that the composite is prepared successfully.In the forth chapter,the composite is investigated by cyclic voltammetry,Constant Current Charge or Discharge and Electrochemical Impedance Spectroscopy.The result indicates that the electrochemical performances of the composite are significantly improved.When the content of graphene is up to 0.8 wt%,a high specific capacitance of 734 F g-1 was abtained at a current density of 0.2 A g-1 and remains 82.3%of the initial value after 500 cycles.The result will be beneficial for developing supercapacitor towards high capacitive performances in the future.The last chapter we give a summary and outlook on the future...