An all solid-state thin film supercapacitor ~TFSC! was fabricated with an amorphous ruthenium oxide (RuO2) thin film electrode and an amorphous LixPOyNz ~Lipon! thin film electrolyte. The electrochemical behavior of the RuO2 /Lipon/RuO2 /Pt TFSC was characterized by a charge-discharge technique in the potential range of 0-2 V. The RuO2 /Lipon/RuO2 /Pt TFSC exhibited a behavior of a bulk-type supercapacitor, even though the capacity of an as-fabricated TFSC was found to be much lower than the bulk one and showed a rapid decrease in capacity. This can be explained by excess oxygen ions and interfacial structure modification. The discharge yield dropped by 53% after 500 cycles. The capacitance per volume of the RuO2 /Lipon/RuO2 /Pt TFSC at the first cycle is 38 mF/cm2 mm.

2001 The Electrochemical Society. @DOI: 10.1149/1.1350666# All rights reserved.