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Electrochemical Impedance Imaging on Conductive Surfaces
Journal article   Peer reviewed

Electrochemical Impedance Imaging on Conductive Surfaces

Yaping Shi, Guangxia Feng, Xiaoliang Li, Xu Yang, Abdulsattar H Ghanim, Paul Ruchhoeft, David Jackson, Syed Mubeen and Xiaonan Shan
Analytical chemistry (Washington), Vol.93(36), pp.12320-12328
09/14/2021
DOI: 10.1021/acs.analchem.1c02040
url
https://www.osti.gov/biblio/1859279View
Open Access

Abstract

Electrochemical impedance spectroscopy (EIS) is a powerful tool to measure and quantify the system impedance. However, EIS only provides an average result from the entire electrode surface. Here, we demonstrated a reflection impedance microscope (RIM) that allows us to image and quantify the localized impedance on conductive surfaces. The RIM is based on the sensitive dependence between the materials’ optical properties, such as permittivity, and their local surface charge densities. The localized charge density variations introduced by the impedance measurements will lead to optical reflectivity changes on electrode surfaces. Our experiments demonstrated that reflectivity modulations are linearly proportional to the surface charge density on the electrode and the measurements show good agreement with the simple free electron gas model. The localized impedance distribution was successfully extracted from the reflectivity measurements together with the Randles equivalent circuit model. In addition, RIM is used to quantify the impedance on different conductive surfaces, such as indium tin oxide, gold film, and stainless steel electrodes. A polydimethylsiloxane-patterned electrode surface was used to demonstrate the impedance imaging capability of RIM. In the end, a single-cell impedance imaging was obtained by RIM.

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