Characteristics of thin film supercapacitor with ruthenium oxide electrode and Ta sub(2)O sub(5+x) solid oxide thin film electrolyte

• Published in: Journal of electroceramics Vol. 17; no. 2-4; pp. 639 - 643
• Main Authors: Lee, Man-Jong, Kim, Joo Sun, Choi, Sun Hee, Lee, Jae Joon, Kim, Soo Ho, Jee, Seung Hyun, Yoon, Young Soo
• Format: Journal Article
• Language: English
• Published: 01.12.2006
• Subjects: Capacitors; Electrodes; Electrolytes; Oxides; Ruthenium oxide; Supercapacitors; Tantalum oxides; Thin films
• ISSN: 1385-3449; 1573-8663
• DOI: 10.1007/s10832-006-7777-z

We report findings related to a solid-state thin film supercapacitors (TFSCs) fabricated with ruthenium oxide electrodes and hydrogen doped tantalum oxide electrolyte in order to investigate a feasibility for solid oxide thin film electrolyte in all solid state micropower sources with hydrogen conducting electrolyte. The TFSCs in this study has a cell structure of RuO sub(2)/Ta sub(2)O sub(5 )/RuO sub(2)/Pt. Radio frequency, off-axis r.f. sputtering deposition of a Ta sub(2)O sub(5) thin film was performed on the bottom amorphous RuO sub(2) electrode which was deposited by an on-axis direct current reactive sputtering, within hydrogen atmosphere to enhance the concentration of mobile proton (H super(+)) ions. Scanning electron microscopy (SEM) measurements reveal that the RuO sub(2)/Ta sub(2)O sub(5 )/RuO sub(2) hetero-interfaces have no inter-diffusion problems. Room temperature charge-discharge measurements with constant current clearly reveal typical supercapacitor behavior. Also, owing to the fast diffusion of H super(+) ions within the Ta sub(2)O sub(5) lattice without any structural deterioration, the capacitance per volume of RuO sub(2)/Ta sub(2)O sub(5 )/RuO sub(2)/Pt TFSCs was maintained to be constant during above 800 cycles. This result indicated that the solid oxide thin film has possibility as the solid proton conducting electrolyte for all solid state micropower sources.