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Manganese Oxide Nanoparticle Synthesis by Thermal Decomposition of Manganese(II) Acetylacetonate
Published on: June 18, 2020
Surface characterisation of chemically reduced electrolytic manganese dioxide
Aaron P Malloy1, Scott W Donne
1Discipline of Chemistry, University of Newcastle, Callaghan, NSW 2308, Australia.
Journal of Colloid and Interface Science
|January 22, 2008
Summary
Chemically reduced electrolytic manganese dioxide (EMD) exhibits amphoteric surface properties with distinct acidic and basic hydroxyl groups. Reduction increases basicity and hydroxyl groups, impacting electrochemical performance.
Area of Science:
- Materials Science
- Electrochemistry
- Surface Chemistry
Background:
- Electrolytic manganese dioxide (EMD) is a key material in battery technology.
- Understanding the surface properties of EMD is crucial for optimizing its electrochemical performance.
- Chemical reduction alters the surface chemistry and properties of EMD.
Purpose of the Study:
- To characterize the amphoteric surface properties of chemically reduced EMD samples.
- To investigate the relationship between the degree of reduction and surface characteristics.
- To correlate surface properties with electrochemical performance.
Main Methods:
- Titration technique to determine acidic and basic hydroxyl group concentrations and equilibrium constants.
- Crystallographic calculations to determine surface oxide and hydroxyl sites.
- Electrochemical analysis in 9 M KOH to assess battery capacity and charge contribution.
Main Results:
- EMD surface consists of independent acidic and basic hydroxyl groups.
- Chemical reduction increases basic site concentration (Kb) and weakens Mn-O bonds.
- Acidic site concentration (Ka) initially decreases then increases slightly at higher reduction levels.
- Calculated and titrated surface hydroxyl groups show good agreement and increase with reduction.
- Electrochemical capacity decreases with increasing reduction, with altered charge contributions from different MnO2 domains.
Conclusions:
- Chemical reduction significantly modifies the amphoteric surface properties of EMD.
- The observed changes in surface chemistry directly influence the electrochemical behavior of EMD.
- The study provides insights into the structural and chemical changes governing EMD performance in batteries.
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