Anodic electrodeposition of redoxable film from manganese oxide nanosheet

Abstract

Manganese oxide electrodeposited films were grown from the solutions containing manganese oxide nanosheet colloid. The nanosheet solutions were prepared by exfoliation of protonated layered manganese oxide by acid treatment of Na- or K-birnessite. The amount of deposit depends on the size of nanosheet, the concentration of added tetrabutylammonium salt and the current between electrodes. The thick film was deposited at low concentration of the salt; however, it was prone to peel off during deposition in the solution. The smooth and flat film can be prepared from the solution with tetrabutylammonium chloride concentration of 1.66 mmol/dm3. The grown films were examined for electrochemical properties by galvanostatic charge-discharge curves and cyclic voltammograms in the NaClO4 acetonitrile solution. The maximum capacitance estimated by the charge-discharge curves was around 224 F/g; however, the capacitance decrease logarithmically depending on the mass of deposit. The obtained cyclic voltammograms with ideal rectangle shape seemed to result from the electric double layer rather than redox reaction. Therefore, these voltammograms confirm that such capacitive behaviors are possibly controlled by iondiffusion through the films. © 2008 The Ceramic Society of Japan. All rights reserved.