(533c) Measurement of Ionic Conductivity of Intact Battery Electrodes Using a Four-Line Probe

Measurement of Ionic Conductivity of Intact Battery Electrodes
Using a Four-Line Probe

In order to optimize Li-ion battery performance, an accurate
understanding of ionic and electronic conductivity within the porous electrode
is needed. Measuring effective ionic conductivity for an electronically
conductive battery electrode is a challenge, since for commonly used techniques
electronic conductivity contributes to the measured conductivity. To remedy
this problem, our research group has previously measured ionic conductivity
using a polarization-interrupt method; however, the prior work required a
destructive test, namely that the electrode film was delaminated from its
current collector. The goal of this work is to measure local effective ionic
conductivity for an intact battery electrode. To do this we are using a micro-four-line-probe
technique which is related to the commonly used four-point-probe method. Effective
conductivity of the thin-film electrode at multiple locations can be calculated
using an apparent resistance determined by the probe combined with a shape
factor determined by a mathematical model. To test the method, the ionic
conductivities of representative cathode and anode films as well as separators
were determined. To validate the new method, results are compared to those of
previous methods.

	Fig. 1.  Micro-four-line-probe with electrode film sample on top.