Super-capacitors Of Ruo <sub> 2 </ Sub> And (ru-sn) The O <sub> 2 </ Sub> Thin Film Electrode Materials Preparation Process And Its Performance

The dissertation got three films of RuO₂·nH₂O, SnO₂·nH₂O and (Ru-Sn)O₂·nH₂O on tantalum substrate by electrodepositon. Morphology and phase were studied by metallography microscopy, scan electron microscopy and x-ray diffraction. Capacitance of three films were studied by the electrochemical system of CH660B. It focused on the pretreatment of substrate, composition of electrolyte and optimization, technology of electrodepositon and optimization, effect of heat-treatment on capacitance of three films. The effct of molar concentration ratio of Ru³⁺ and Sn²⁺ in the initial electrodepositon bathe to the performance of (Ru-Sn) O₂·nH₂O films were also studied. The main results are as follows:(1) The optimum deparameter electrodepositon of RuO₂·nH₂O , SnO₂·nH₂O and (Ru-Sn) O₂·nH₂O films as follows: 25℃is a optimum temperature of electrolyte. 0.075 mol·L^-1 is a optimum concentration of NaNO₃ .The optimum concentration of solution is 10mM(RuCl3·2H₂O),5 mM(SnCl₂·2H₂O),5mM and 10mM(RuCl-3·2H₂Oå'ŒSnCl₂·2H₂O) ; The optimum cathodic current density is 10,5 and 8 mA·cm^-2. The optimum initial PH is 2.3,1.6 and 2.0. The optimum time of electrodeposition is 2h, 3h and 3h; The electrodepositon of SnO₂·nH₂O and (Ru-Sn) O₂·nH₂O films need to have a concentration of HNO₃ solution 0.01 mol·L^-1 in the initial electrodepositon solution.(2) Heat-treatment can improve the capacitance stability of RuO₂·nH₂O film, but special capacitance of RuO₂·nH₂O film increase and then decrease with the ascent of temperature. Maximum of special capacitance occur when the temperature of heat-treatment is about 100℃. The maximum capacity reached 563 F/g, the adhension also reached 11.3 MPa.(3) The adhension of SnO₂·nH₂O films can be improve by the increase of the heat-treatment temperature between 100℃to 300℃. The max adhension of SnO₂nH₂O films is 12MPa when the heat-treatment temperature was 300℃; When the heat-treatment temperature above 300℃, the adhension of SnO₂·nH₂O films decrese deaply.(4) By the increase of the heat-treatment temperature , the capacitance of SnO₂·nH₂O films can be improve firstly, but the increased.The max capacitance of SnO₂·nH₂O films is 262F/g,when the heat-treatment temperature is 100℃and the heat-treatment is 3 hours.(5) By the increase of the Sn²⁺ in the initial electrodepositon bathe, the capacitance of (Ru-Sn)O₂·nH₂O films will be decreased.When the molar concentration ratio of Sn²⁺ and Ru³⁺ in the initial electrodepositon bathe change from 1:0.5 to 3:1, the capacitance of (Ru-Sn)O₂·nH₂O films change from 350F/g to 321F/g, only have a decreasion of 8.3%. 1:2 is a optimum molar concentration ratio of Sn²⁺ and Ru³⁺ in the initial electrodepositon bathe. At that condition, the capacity os (Ru-Sn)O₂·nH₂O films reached 330 F/g and the adhension reached 12.8 MPa.