- Title
- Electrodeposition mechanism of cathodically-prepared manganese dioxide thin films from permanganate for use in electrochemical capacitors
- Creator
- Gibson, Andrew J.; Latham, Kenneth G.; Burns, Robert C.; Donne, Scott W.
- Relation
- Electrochimica Acta Vol. 236, p. 198-211
- Publisher Link
- http://dx.doi.org/10.1016/j.electacta.2017.03.014
- Publisher
- Elsevier
- Resource Type
- journal article
- Date
- 2017
- Description
- Herein the various steps in the electrodeposition mechanism of manganese dioxide from permanganate are elucidated. Two primary mechanisms are described, dependent on applied potential and hydrodynamics. The first is a combined reduction and disproportionation reaction involving the reduction of MnO₄⁻ to MnO₄²⁻, which subsequently hydrolyses and disproportionates to form the Mn(V) species H₂MnO₄⁻. This is then further reduced to form manganese dioxide. This reaction continues over the whole potential range, however whether the system is dynamic or static has an effect on this, with the former leading to continued reaction from an influx of MnO₄⁻, and the latter not having available MnO₄⁻ to proceed. The second mechanism involves a dissolution of already existing manganese dioxide, through a MnOOH intermediate to form aqueous Mn²⁺. This Mn²⁺ then reacts with MnO4⁻ in solution to form manganese dioxide. These mechanisms have been substantiated with scanning electron microscopy and X-ray photoelectron spectroscopy. The performance of these materials as capacitor electrodes has also been investigated, achieving 363 F/g when cycled at 25 mV/s.
- Subject
- electrochemical capacitors; electrodeposition; permanganate; manganese dioxide
- Identifier
- http://hdl.handle.net/1959.13/1395424
- Identifier
- uon:33879
- Identifier
- ISSN:0013-4686
- Language
- eng
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