Capacitive Properties and Structure of RuO2-HfO2 Films Prepared by Thermal Decomposition Method

Binary RuO2-HfO2 films on Ti substrates were prepared by a thermal decomposition method. cyclic voltammetric and charge/discharge properties of the RuO2-HfO2 electrodes were characterized. It was determined that the incorporation of HfO2 into RuO2 greatly improved the capacitive properties of the material. The RuO2-HfO2 electrodes showed excellent cyclic stability, with no decay in charge capability during 1000 CV cycles in acidic solution. A nominal content of 50 mol% RuO2 and 50 mol% HfO2 gave the highest specific capacitance of 789.3 F/g (RuO2). The excellent capacitive properties and stability were related to the hydrous amorphous mixed-oxides formed in the film. This work proves that high capacitive performance of RuO2-based electrode materials can be obtained by thermal decomposition, even with the retained chloride in the film.