Preparation Of Nitrogen Doped Carbon Materials And Their Capacitance Performance For Supercapacitor

Supercapacitor, as a new type of energy storage device, have the superior properties of high power density, long cycle life, wide range of temperature adaptation and fast charging and discharging rate and become the research focus in the field of energy today. Electrode materials are usually considered to play the crucial role in the supercapacitors, whose composition and structure can affect the overall performance and the application fields of the supercapacitors. Carbon nanomaterials have unique physical and chemical and electronic properties, on the basis of it the research will have broad prospect of application of electrode materials. High specific surface area, suitable pore structure, surface chemical properties, good conductivity and high price Ratio are the main indicator of evaluation index of carbon materials as excellent electrochemical capacitor electrode material. Studies show that nitrogen atoms doped carbon materials can effectively improve the wettability of carbon materials, conductivity and capacitance performance. In this paper, in order to improve the electrochemical properties of the carbon material to proceed, we synthesized a series of different morphologies of nitrogen-doped carbon material. Morphologies of products were characterized by scanning electronmicroscope(SEM) and transmission electronmicroscope(TEM).The crystal structures were studies by X ray diffraction(XRD). X-ray photoelectron spectroscopy(XPS) and elemental analysis(CHN), infrared spectroscopy(IR) to characterize the material properties by means of surface chemistry and elemental composition analysis. Supercapacitive behaviors were investigated by cyclic voltammetry tests(CV), galvanostatic charge/discharge curves(GCD) and electrochemicalimpedance spectroscopy(EIS). The main contents are as follows:1. The three-dimensional Nitrogen-doped Carbon(3D N-CNs) were developed by an integrated and facile strategy to prepare using pyrrole monomer as nitrogen source and carbon source, FeCl3 as oxidant and carbonization catalyst. In the synthesis process, the FeCl3 serves as an oxidant for oxidative polymerization of pyrrole monomers. Simultaneously, it serves as the carbonization catalyst to promote nitrogen-doped carbon nanomaterials formation. More attractively, the surface area, pore size can be adjusted by changing the molar ratio of FeCl3 and Ppy. 2. Nitrogen doped carbon nanomaterials were synthesized by hydrothermal treatment with Urea, Ammonium, Melamine, Triethanolamine, Triethylenediamine, ethylenediamine, Ethylenediamine as nitrogen source and Reduced graphene oxide as carbon source, high temperature calcined under nitrogen protection. Research results showed that the preparation of melamine as the nitrogen source of nitrogen doped graphene has a relatively high nitrogen content, larger specific surface area and high specific capacitance. 3. Melamine as nitrogen, formaldehyde resin as a carbon source, tri-block copolymer F127 as a soft template, potassium hydroxide as activating agent prepared by controlled synthesis of nitrogen-doped mesoporous carbon. BET characterization results showed that the honeycomb nitrogen doped carbon materials with high specific surface area of 2094.28 m2 g-1. The electrochemical test results showed that the introduction of a nitrogen atom, a substantial increased in the electrochemical activity of the ordered mesoporous carbon material, the current density of 0.5 A g-1 ratio when the capacitance of up to 409 F g-1, When the current density increased by 0.5A g-1 to 20 A g-1 when the specific capacitance of 320 F g-1, its retention rate as high as 78.3%, indicating that the honeycomb nitrogen doped carbon material has excellent rate performance. At the same time, the material also has a good cycle stability(10000 laps after retention rate of 98%). Research results showed that the honeycomb nitrogen doped carbon material is a great value electrode material.In this thesis, different small organic molecules were selected as the precursors. Fabrication of novel N-doped carbon materials with controlled structure and composition were realized through synthetic route design and optimization. Such N-doped carbon materials could dramatically enhance the supercapacitor performances.