Comparative Operando XPS and SEM Spatiotemporal Potential Mapping of Ionic Liquid Polarization in a Coplanar Electrochemical Device
Andrei Kolmakov, Evgheni Strelcov
The polarization response of a co-planar electrochemical capacitor covered with an ionic liquid as the electrolyte has been examined by a combination of two powerful analytic techniques, X-Ray Photoelectron Spectroscopy and Secondary Electron Microcopy. Spatio-temporal distribution of the ionic liquid surface potential, upon DC or AC (Square-Wave) biasing has been monitored via binding energy shifts using XPS and secondary electrons intensity variations using SEM. The magnitude of the electrical potential can be quantified with XPS which has a higher chemical specificity. SEM, with its higher spatial and temporal resolution, in conjunction with a data mining algorithm, enables mapping of the surface potential distribution across the capacitor. Interestingly, despite the differences in the detection principles, both techniques yield similar polarization relaxation time constants. This demonstrates the power of a synergistic combination of the two techniques with complementary capabilities.
and Strelcov, E.
Comparative Operando XPS and SEM Spatiotemporal Potential Mapping of Ionic Liquid Polarization in a Coplanar Electrochemical Device, Analytical Chemistry, [online], https://doi.org/10.1021/acs.analchem.1c02779, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=932555
(Accessed February 27, 2024)