Improved experimental setup to reach a broad frequency domain in local electrochemical impedance spectroscopy measurements

Abstract

We report a new experimental setup enabling local electrochemical impedance spectroscopy (LEIS) measurements over a wide frequency range, including the low frequency domain. First, an improved signal treatment was performed using a potential shifter to minimize the DC component of the measured potential, allowing for the local AC potential to be probed using an ideal electrochemical system. Then, a unique, three-electrode LEIS probe was implemented to study the influence of radial and lateral contributions on the LEIS response. The radial LEIS response is highest when the LEIS probe is positioned in the middle of the gold electrode substrate, whereas the lateral LEIS response is similar in both measured regions. Both experimental modifications were implemented to study the LEIS response over a corroding aluminum substrate, for which reliable results are obtained in the low frequencies. These tools could be used in future LEIS studies in other fields that require time-sensitive measurements.