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Molecular adsorption at electrolyte/α-Al2O3interface of aluminum electrolytic capacitor revealed by sum frequency vibrational spectroscopy
- Source :
- The Journal of Chemical Physics. 146:194706
- Publication Year :
- 2017
- Publisher :
- AIP Publishing, 2017.
-
Abstract
- The operating voltage of an aluminum electrolytic capacitor is determined by the breakdown voltage (Ub) of the Al2O3 anode. Ub is related to the molecular adsorption at the Al2O3/electrolyte interface. Therefore, we have employed sum-frequency vibrational spectroscopy (SFVS) to study the adsorption states of a simple electrolyte, ethylene glycol (EG) solution with ammonium adipate, on an α-Al2O3 surface. In an acidic electrolyte (pH < 6), the Al2O3 surface is positively charged. The observed SFVS spectra show that long chain molecules poly ethylene glycol and ethylene glycol adipate adopt a “lying” orientation at the interface. In an alkaline electrolyte (pH > 8), the Al2O3 surface is negatively charged and the short chain EG molecules adopt a “tilting” orientation. The Ub results exhibit a much higher value at pH < 6 compared with that at pH > 8. Since the “lying” long chain molecules cover and protect the Al2O3 surface, Ub increases with a decrease of pH. These findings provide new insights to study the breakdown mechanisms and to develop new electrolytes for high operating voltage capacitors.
- Subjects :
- Inorganic chemistry
Analytical chemistry
General Physics and Astronomy
02 engineering and technology
Electrolyte
010402 general chemistry
021001 nanoscience & nanotechnology
01 natural sciences
0104 chemical sciences
law.invention
Ammonium adipate
Anode
ARTICLES
Capacitor
chemistry.chemical_compound
Adsorption
chemistry
law
Aluminum electrolytic capacitor
Breakdown voltage
Physical and Theoretical Chemistry
0210 nano-technology
Ethylene glycol
Subjects
Details
- ISSN :
- 10897690 and 00219606
- Volume :
- 146
- Database :
- OpenAIRE
- Journal :
- The Journal of Chemical Physics
- Accession number :
- edsair.doi.dedup.....63656bae81ac15c3176d307a1ce9d9d3