钽电容器用钽壳内壁RuO_2薄膜电极的表征及电化学性能

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

采用涂覆热分解氯化钌的方法,在金属钽壳内壁表面形成二氧化钌薄膜涂层,作为钽电容器的负极材料,可以提高全钽电容器的寿命及可靠性.采用扫描电子显微镜和X射线衍射仪对二氧化钌薄膜的表面形貌和结构进行表征.采用循环伏安、恒流充放电和电化学阻抗谱等测试手段来表征二氧化钌薄膜电极的电化学性能.研究结果表明,热处理温度为280℃时制备的二氧化钌薄膜呈无定形的非晶态,薄膜电极具有212F/g的电容量,电化学性能良好.组装成ST3型60V330μF全钽电容器,经过赋能、电老化后容量约为345μF,等效串联电阻小于1Ω,漏电流小于10μA.

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.