Experimental Limitations in Impedance Spectroscopy. Part 3. Effect of Reference Electrode Geometry/Position.
Experimental Limitations in Impedance Spectroscopy.
Part 3. Effect of Reference Electrode
Geometry/Position.
(1191 K)
Hsieh, G.; Mason, T. O.; Garboczi, E. J.; Pederson, L.
R.
Solid State Ionics, Vol. 96, 153-182, 1997.
Keywords:
impedance spectroscopy; building technology; counter;
electrodes; electrolyte; pseudoreference; reference;
simulation; working
Abstract:
Experiments and computer simulations on Pt/YSZ specimens
in various electrode configurations were performed to
investigate the effect of reference electrode
geometry/position on the accuracy of impedance
measurements. The internal, Luggin probe-type, geometry
is the preferred reference electrode configuration as it
accurately measures both electrolyte and electrode
impedances. External, 'pseudoreference', electrodes
sample an averaged effective potential and can register
inaccurate electrolyte resistances, sometimes with
distorted electrode arcs. A symmetric configuration can
accurately measure the impedance of an electrode;
however, the electrolyte resistance will not scale
linearly according to sample dimensions, as one might
exptect. An asymmetric configuration exhibits both
non-linear partitioning of electrolyte resistance and
distortions in the electrode impedance arc under certain
circumstances. The reliability of three-electrode
measurements is very sensitive to aspect ratio and
electrode configuration.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899