Minimizing Artifacts in Three-electrode Double Layer Capacitance Measurements Caused by Stray Capacitances

摘要

We analyze the influence of stray capacitances on three-electrode electrochemical impedance measurements with ion-blocking electrodes. This setup is widely used for double layer capacitance measurements. The analysis is based on a three-terminal equivalent network and reveals that stray capacitances lead to different types of capacitive and inductive artifacts. We show that the type of artifact depends strongly on (i) the positioning of the reference electrode between the working and the counter electrode and (ii) on ratio of the double layer capacitance of the working electrode to the stray capacitances. We compare the theoretical results to experimental results obtained for the double layer capacitance of the working electrode in three electrochemical cells with different areas and positions of the electrodes. On the basis of this work, we give advice on how to minimize and/or correct three-electrode artifacts in double layer capacitance measurements. (C) 2015 Elsevier Ltd. All rights reserved.