Preparation And Characterization Of Ruthenium Oxide（RuO₂） Based Composite Film Electrode For Supercapacitor

Electrochemical supercapacitor has been recognized as a new type of energy storage devices that fill the gap between batteries and conventional capacitors. Supercapacitors have many characteristics, such as high specific capacitance, high power density, short time of charge, long cycle life. RuO2, which is based on faraday charge-discharge(CD) principle, has been the key electrode material to make supercapacitors. However, the application of RuO2is limited due to its high cost. So, RuO2-based electrode materials have become the research focus today.In this thesis, we used sol-thermal decomposition, colloidal and combination(coating-thermal decomposition and electrodeposition) meth-ods to prepare RuO2-based silica, cobaltosic oxide, and polyaniline composite electrodes, respectively. The structure, morphology and electrochemical performances of these electrods were characterized by XRD, SEM, FT-IR, CHI660C and so on. Got the following main results:1. We prepared (RuO2/SiO2)-nH2O composite film electrode by sol-thermal decomposition method, also explored and optimized the preparation technology. If the molarity ratio of RuCl3·3H2O and TEOS was10:3, the film electrode got best property after sintered2h at35O℃. The results of adhesion testing was21.2MPa, respectively. The film electrode exhibited the best electrochemical property, when we chose H2SO4as electrolyte, its specific capacitance was421F/g, and the inner resistance was about0.49Ω; Besides, its CD curves were symmetrical, which symbolized its hgih CD efficiency.2. Using colloidal method to prepare (RuO2/Co3O4)·nH2O film electrode, we explored the influence which the molar ratio n(Co):n(Ru) of Co2+and Ru3+, sintering temperature and time affected on the film electrode’s morphology, composition structure and property. Besides, we researched the film’s electrochemical behaviour in acid, neutral and alkaline solution, when n(Co):n(Ru)=2:1, the film electrode prepared after sintered at350℃for2.5h exhibited best comprehensive property in acid electrolyte(0.5mol/L H2SO4), RuO2and Co3O4both showed pseudoc-apacitance characteristic. It had high specific capacitance (512F/g, which still kept at96.1%after500CD cycles), long discharge time(1800s) and slihgtly higher inner resistance(1.2Ω).3. Prepared (RuO2/PANI)·nH2O composite film electrode by combination method. This method has sol-thermal decomposition’s advantage of low cost, high adhesion and the electrochemical decompostion’s advantage of simple process, which could provide us ideal electrode materials. This chapter revealed the effect principals that the aniline monomer(AN) concentration, current density and electrodeposition time affected on the morphology and performance of the electrode. When they were0.25mol/L,2mA/cm,15min, respectively, the film electrode had the best comprehensive performance. Its specific surface area and inner resistance was362m/g and0.64Ω, respectively. Besides, the specific capacitance could be458F/g when the scan rate was5mV/s, which decayed12%after1000CD cycles, but the decrease mostly happened at the initial stage, the electrode had high stability.