Electrochemical Capacitor Behavior of Layered Ruthenic Acid Hydrate

A hydrous ruthenic acid possessing a layered structure with a crystalline framework was prepared by proton exchange of a layered potassium ruthenate. Its electrochemical capacitor behavior was studied by cyclic voltammetry in various electrolytes. Specific capacitance up to 390 F at a scan rate of 50 mV s −1 , which is a ten-fold increase compared to conventional anhydrous was obtained using layered ruthenic acid hydrate in 0.5 M electrolyte. Slightly lower values were obtained for 1 M and 1 M KOH electrolytes. The difference in the specific capacitance of anhydrous ruthenium oxide, hydrous ruthenium oxide, hydrous ruthenic acid, and restacked ruthenic acid nanosheets in the various electrolytes is discussed. © 2004 The Electrochemical Society. All rights reserved.