Journal article

Publication year: 2021

Journal: Scientific Reports

Volume number: 11

Issue number: 1

ISSN: 2045-2322

Open access status: Gold

DOI Link: https://doi.org/10.1038/s41598-021-96602-2

Publisher: Nature Research

Abstract: 
Electrochemical strain microscopy (ESM) has been developed with the aim of measuring Vegard strains in mixed ionic-electronic conductors (MIECs), such as electrode materials for Li-ion batteries, caused by local changes in the chemical composition. In this technique, a voltage-biased AFM tip is used in contact resonance mode. However, extracting quantitative strain information from ESM experiments is highly challenging due to the complexity of the signal generation process. In particular, electrostatic interactions between tip and sample contribute significantly to the measured ESM signals, and the separation of Vegard strain-induced signal contributions from electrostatically induced signal contributions is by no means a trivial task. Recently, we have published a compensation method for eliminating frequency-independent electrostatic contributions in ESM measurements. Here, we demonstrate the potential of this method for detecting Vegard strain in MIECs by choosing Cu2Mo6S8 as a model-type MIEC with an exceptionally high Cu chemical diffusion coefficient. Even for this material, Vegard strains are only measurable around and above room-temperature and with proper elimination of electrostatics. The analyis of the measured Vegards strains gives strong indication that due to a high charge transfer resistance at the tip/interface, the local Cu concentration variations are much smaller than predicted by the local Nernst equation. This suggests that charge transfer resistances have to be analyzed in more detail in future ESM studies.

Harvard Citation style: Badur, S., Renz, D., Cronau, M., Goeddenhenrich, T., Dietzel, D., Roling, B., et al. (2021) Characterization of Vegard strain related to exceptionally fast Cu-chemical diffusion in Cu₂Mo₆S₈ by an advanced electrochemical strain microscopy method, Scientific Reports, 11(1), Article 18133. https://doi.org/10.1038/s41598-021-96602-2

APA Citation style: Badur, S., Renz, D., Cronau, M., Goeddenhenrich, T., Dietzel, D., Roling, B., & Schirmeisen, A. (2021). Characterization of Vegard strain related to exceptionally fast Cu-chemical diffusion in Cu₂Mo₆S₈ by an advanced electrochemical strain microscopy method. Scientific Reports. 11(1), Article 18133. https://doi.org/10.1038/s41598-021-96602-2