Study on Reaction Mechanism of MnFe2O4 Supercapacitors by EQCM
Date Issued
2009
Date
2009
Author(s)
Su, Mei-Hui
Abstract
Electrodeposition of MnFe2O4 film was succesfully prepared by using anodic electroplating method from optimized precusors composed of MnSO4 and FeSO4 solutions. After calcination of as-deposited film, from EDX and XRD analysis, film composition was attributed to 97.4% amount of MnFe2O4 and 2.6% amount of Fe3O4, as a co-deposited MnFe2O4 film electrode. In addition, film electrodes annealed at low temperature showed more likely current profiles for supercapacitors in NaCl(aq).urthermore, pseudocapacitive charge-storage reaction of MnFe2O4 in several aqueous alkali salts, alkaline salts and sulfate solutions, including LiCl, NaCl, KCl, CaCl2 and Na2SO4, has been studied on sprayed MnFe2O4 thin-films. Electrochemical quartz-crystal microbalance and X-ray photoelectron spectroscopy data further indicated that, the predominant reduction/oxidation of the Mn ions at the tetrahedral sites of the spinel was mainly balanced by insertion/extraction of the solution cations, H3O+, Li+ and Ca+2 into/from the ferrite structure while in NaCl, LiCl and CaCl2 electrolytes respectively, or balanced by some extent of chemisorption of K+ on ferrite surface along with insertion/extraction of H3O+ into the bulk materials in KCl solution.
Subjects
supercapacitor
MnFe2O4
EQCM
reaction mechanism
Type
thesis
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