Characterization and Electrochemical Properties of RuO_2 Film Electrode on the Inner-wall of Tantalum Shell for Capacitor

Using the methods of coated and thermal decomposed ruthenium chloride,the RuO_2 thin film was synthesized on the inner-wall surface of tantalum shell.Its morphology and structure were characterized by scanning electron microscope and X-ray diffraction.The electrochemical performances of the RuO_2 thin film electrode were tested by cyclic voltammetry,galvanostatic charging/discharging and electrochemical impedance spectroscope.The results show that the RuO_2 thin film calcinated at 280℃has amorphous structure and the specific capacitance of the electrode is 212F/g(in 0.5 mol/L H_2SO_4 electrolyte) with good electrochemical performance.When the films are assembled into ST3 type 60 V 330μF tantalum capacitors,the capacitance can still maintain 345μF after celaring and electrical aging.The equivalent series resistance(ESR) is less than 1Ω,and the leakage current is less than 10μA.