Fabrication and characterization of a SnO2−RuO2 composite anode for a hybrid thin film battery

Abstract

A SnO2−RuO2 composite (SnRuO) thin film possesses unique electrochemical properties for a hybrid between batteries and supercapacitors due to the fact that the SnRuO system shows battery and supercapacitor characteristics simultaneously. SnRuO thin films were prepared through the magnetron co-sputtering method in order to investigate the feasibility of a monolithic thin film hybrid battery. The SnRuO thin film as an anode film for a secondary battery demonstrated a first discharge capacity of 1557 μAh/cm2·μm; the second discharge capacity was 52% of the first discharge capacity. The degree of capacity fade of the SnRuO thin film was almost the same as that of the SnO2 thin film, even though the capacity of the SnRuO thin film was larger than that of the pure SnO2. In addition, the SnRuO thin film showed a supercapacitor behavior and exhibited a specific capacitance of 14 mF/cm2 μm during 1000 cycles. These results suggest that SnRuO thin film could be used as a thin film supercapacitor as well as a thin film battery. Furthermore, this composite thin film holds promise for the fabrication of a monolithic thin film high power hybrid battery based on micro-processes.