Measuring individual overpotentials in an operating solid-oxide electrochemical cell.
We use photo-electrons as a non-contact probe to measure local electrical potentials in a solid-oxide electrochemical cell. We characterize the cell in operando at near-ambient pressure using spatially-resolved X-ray photoemission spectroscopy. The overpotentials at the interfaces between the Ni and Pt electrodes and the yttria-stabilized zirconia (YSZ) electrolyte are directly measured. The method is validated using electrochemical impedance spectroscopy. Using the overpotentials, which characterize the cell's inefficiencies, we compare without ambiguity the electro-catalytic efficiencies of Ni and Pt, finding that on Ni H(2)O splitting proceeds more rapidly than H(2) oxidation, while on Pt, H(2) oxidation proceeds more rapidly than H(2)O splitting.
El Gabaly
Farid
F
Sandia National Laboratories, CA 94550, USA. felgaba@sandia.gov
Grass
Michael
M
McDaniel
Anthony H
AH
Farrow
Roger L
RL
Linne
Mark A
MA
Hussain
Zahid
Z
Bluhm
Hendrik
H
Liu
Zhi
Z
McCarty
Kevin F
KF