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Measuring individual overpotentials in an operating solid-oxide electrochemical cell
Farid El Gabaly1, Michael Grass, Anthony H McDaniel
1Sandia National Laboratories, CA 94550, USA. felgaba@sandia.gov
Physical Chemistry Chemical Physics : PCCP
|August 10, 2010
Summary
Photo-electrons probe electrical potentials in solid-oxide electrochemical cells. This reveals that Ni electrodes favor water splitting, while Pt electrodes favor hydrogen oxidation, offering insights into catalytic efficiency.
Area of Science:
- Electrochemistry
- Materials Science
- Spectroscopy
Background:
- Solid-oxide electrochemical cells are crucial for energy conversion.
- Understanding interfacial electrical potentials is key to optimizing cell performance.
- Current methods for measuring these potentials can be invasive or lack spatial resolution.
Purpose of the Study:
- To develop and validate a non-contact method for measuring local electrical potentials in solid-oxide electrochemical cells.
- To directly quantify overpotentials at electrode-electrolyte interfaces.
- To compare the electro-catalytic efficiencies of Nickel (Ni) and Platinum (Pt) electrodes.
Main Methods:
- Utilizing photo-electrons as a non-contact probe.
- Employing spatially-resolved X-ray photoemission spectroscopy (sXPS) for in operando characterization.
- Validating measurements with electrochemical impedance spectroscopy (EIS).
Main Results:
- Direct measurement of overpotentials at Ni/YSZ and Pt/YSZ interfaces.
- Demonstrated ability to characterize electrochemical cells under near-ambient pressure.
- Quantified differences in electro-catalytic activity between Ni and Pt electrodes.
Conclusions:
- Photo-electron spectroscopy provides a powerful tool for probing interfacial phenomena in electrochemical cells.
- Ni electrodes exhibit higher efficiency for H(2)O splitting compared to H(2) oxidation.
- Pt electrodes show greater efficiency for H(2) oxidation than H(2)O splitting, highlighting distinct catalytic behaviors.
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