Determining Through-Plane Membrane Conductivity using Four-Electrode EIS

In-plane or through-plane conductivity?

Four-electrode impedance spectroscopy is a really powerful method for studying the ionic conductivity of membranes. However with the common setup, only the in-plane conductivity is being measured, even though the through-plane conductivity is usually the relevant quantity. Using the TCE Cell One, the through-plane conductivity of a membrane can be determined in a simple and reproducible manner, as demonstrated in the application note below.

Two- or four-electrode mode?

Ionic conductivity is one of the key properties of membranes used in fuel cells, redox flow batteries, electrolyzers, and many more applications. Using a four-electrode (rather than a two-electrode) configuration allows for more precise measurements since no current is passing through the sensing electrodes. However, if all four electrodes are placed on one side of the membrane (as it is most commonly applied), surface effects can lead to inaccurate results, only showing the in-plane conductivity. In the TCE Cell One, however, electrodes are placed on either side of the membrane, leading to probing the through-plane conductivity exclusively.

One cell, many configurations

The TCE Cell One presents a simple and versatile way to perform two- or four-electrode measurements on membranes and separators, specifically probing through-plane conductivity! The application note below describes the four-electrode measurement, while a previous application note shows the two-electrode setup.