Self-discharge and potential recovery phenomena at thermally and electrochemically prepared RuO sub(2) supercapacitor electrodes

Films of ruthenium oxide (RuO sub(2)) exhibit large, almost constant capacitance, over a potential range of approximately 1.4 V in aqueous acid solutions. This behaviour has led to their development as supercapacitor materials giving many Farads per gram. Applications of electrochemical capacitors r...

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Bibliographic Details
Published in:Electrochimica acta 1997-01, Vol.42 (23-24), p.3541-3552
Main Authors: Liu, Tongchang, Pell, W G, Conway, B E
Format: Article
Language:English
Online Access:Get full text
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Summary:Films of ruthenium oxide (RuO sub(2)) exhibit large, almost constant capacitance, over a potential range of approximately 1.4 V in aqueous acid solutions. This behaviour has led to their development as supercapacitor materials giving many Farads per gram. Applications of electrochemical capacitors require minimum self-discharge rates. In the present paper, the self-discharge kinetics of charged RuO sub(2) electrodes are studied and a remarkable phenomenon of successive potential recovery after sequential discharge transients is reported. The self-discharge and potential-recovery behaviour is analyzed in terms of a process of diffusion of oxidation state involving proton and electron hopping, treated in a model of the RuO sub(2) film structure having three regions between which redistribution of oxidation states in the oxide film takes place on self-discharge and recovery.
ISSN:0013-4686