Thin film supercapacitors using a sputtered RuO2 electrode

An all solid-state thin film supercapacitor (TFSC) was fabricated with an a morphous ruthenium oxide (RuO2) thin film electrode and an amorphous LixPOy Nz (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-fabricate d TFSC was found to be much lower than the bulk one and showed a rapid decr ease in capacity. This can be explained by excess oxygen ions and interfaci al structure modification. The discharge yield dropped by 53% after 500 cyc les. The capacitance per volume of the RuO2/Lipon/RuO2/Pt TFSC at the first cycle is 38 mF/cm(2) mum. (C) 2001 The Electrochemical Society. All rights reserved.