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Preparation and Characterization of Conducting Polymer Modified Carbon Electrode

Author: FangJingRui
Tutor: WangZuo
School: Ocean University of China
Course: Materials Physics and Chemistry
Keywords: Supercapacitor Polyaniline Activated carbon Specific capacitance
CLC: TM53
Type: Master's thesis
Year: 2007
Downloads: 266
Quote: 2
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Abstract

Super capacitor is a new energy storage element between the battery and the static capacitor between power density than batteries and the high number of times the energy density of the number of times higher than the static capacitor with fast charge and discharge, environmental pollution, long cycle life, etc., is expected to become the new green energy in the 21st century. The supercapacitors study focused on the preparation of high-performance electrode materials. According to the type of energy storage mechanism, supercapacitors can be divided based on the principle of an electric double layer of high surface area carbon deposition material with the solution at the interface between the electric double layer capacitor and quasi (pseudo) based on the electrode material on the surface of the electrodeposited copper or redox processes Faraday super capacitor two types of capacitors. The active carbon material having a high specific surface area can produce a large electric double layer capacitor, the conductive polymer rapidly reversible oxidation-reduction reaction resulting in the entire volume of memory in a high density charge quasi capacitor, and thus the two electrodes The material composite can improve the specific capacitance of the electrode. Activated carbon as the electrode raw materials, and higher than the capacitance carbon electrode by optimizing the process preparation. Adsorption in situ chemical polymerization legitimate and in situ electrochemical polymerization method conductive polymer / activated carbon composite electrode by cyclic voltammetry, AC impedance, constant current charge-discharge test and compare the electrochemical performance. The main experimental content and the results are as follows: an activated carbon electrode preparation and process optimization in this paper a more systematic study of the impact of activated carbon (AC) electrode performance factors and found that the performance of the three and content of carbon, conductive agent, a binder, the electrode forming and other factors on the conductivity and specific capacitance of the electrode has a certain impact. Experiments show that activated carbon smaller the particle size, the greater the specific surface area, mixed with a conductive agent, the better, the higher the conductivity of the electrode; carbon black as a conductive agent, the best electrode performance and carbon black content of more than 30% of the conductivity of the electrode change small, but due to the very small capacitance of the carbon black itself, with its carbon content increases the capacity of the electrode decreased; Teflon insulation and hydrophobic binder content increases significantly decreased when the ratio of the capacitance. The milling can be mixed to improve the mixing of the activated carbon and carbon black, thereby improving the electrical conductivity of the electrode, but when the milling time exceeds 2H conductivity remained unchanged. Therefore ultimately determine the specific surface area of ??2600m ~~ 2 / g of activated carbon powder as the electrode body material, and carbon black, polytetrafluoroethylene ratio of 8: 1: 1, 2h milling processing, 0.5mol / L sulfuric acid as the electrolyte, carbon electrode specific capacitance up to 306F / g, equivalent series resistance of about 16 ohms, the specific capacitance is higher than the values ??reported in the literature. Experiments using activated carbon powder particle size is smaller, the preprocessing means and having a high specific surface area, soaking and heat treatment to improve its performance is not obvious, so wrong activated carbon pretreatment experiment. (2) Chemical Preparation of polyaniline / carbon composite electrode adsorption by in situ chemical polymerization method polyaniline (PAn) mixed with activated carbon particles, both the mass ratio of about 7:1, polyaniline yield of about 61%. 0.5mol / L sulfuric acid as the electrolyte, the Composite Electrode than PAN / AC capacitor reached 390F / g, 28% higher than the pure AC electrodes, than capacitor improvement is due to the polyaniline redox reaction Faraday quasi capacitor , but lower the polyaniline utilization in the electrodes (only 49%), and the equivalent series resistance (ESR) of the composite electrode is higher than the AC electrode, about 80Ω, chemically prepared polyaniline poor conductivity . Electrochemical Preparation of PAN / AC composite electrode by cyclic voltammetry and constant potential at the surface of the activated carbon electrode electrochemical polymerization layer of conductive polyaniline and composite electrode by changing the polymerization conditions, to characterize its performance and compare . Experimental results show that the PAN / AC composite electrode showed significant Faraday Pseudo-capacitance and high specific capacitance than the AC electrode. Aniline oxidation potential of the carbon electrode is higher than the glassy carbon, platinum and other inert electrode around in 1.2V. Cyclic voltammetry prepared composite electrode capacitance performance than the constant potential method. Larger scan cyclic voltammetry polymerization rate can not be obtained polyaniline film, the smaller the potential of the scan limit, the higher the obtained polyaniline redox reversibility, the smaller the equivalent series resistance of the electrode, the effective use of polyaniline on the surface of the activated carbon The higher the rate, the higher specific capacitance. Experiments to determine the polymerization potential sweep range of -0.2 to 1.2V, the scan rate for the 1 mV / s, the polymerization period 3, the polyaniline can achieve effective utilization of 89%, the ratio of the capacitor reaches 546F / g than pure AC electrode to improve 78%.

Preparation and Characterization of Conducting Polymer Modified Carbon Electrode

Abstract

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