Scanning thermo-ionic microscopy for probing local electrochemistry at the nanoscale
- Department of Mechanical Engineering, University of Washington, Seattle, Washington 98195 (United States)
- Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105, Hunan (China)
- Department of Chemical Engineering, University of Washington, Seattle, Washington 98195 (United States)
Conventional electrochemical characterization techniques based on voltage and current measurements only probe faradaic and capacitive rates in aggregate. In this work we develop a scanning thermo-ionic microscopy (STIM) to probe local electrochemistry at the nanoscale, based on imaging of Vegard strain induced by thermal oscillation. It is demonstrated from both theoretical analysis and experimental validation that the second harmonic response of thermally induced cantilever vibration, associated with thermal expansion, is present in all solids, whereas the fourth harmonic response, caused by local transport of mobile species, is only present in ionic materials. The origin of STIM response is further confirmed by its reduced amplitude with respect to increased contact force, due to the coupling of stress to concentration of ionic species and/or electronic defects. The technique has been applied to probe Sm-doped Ceria and LiFePO{sub 4}, both of which exhibit higher concentrations of mobile species near grain boundaries. The STIM gives us a powerful method to study local electrochemistry with high sensitivity and spatial resolution for a wide range of ionic systems, as well as ability to map local thermomechanical response.
- OSTI ID:
- 22596728
- Journal Information:
- Journal of Applied Physics, Vol. 119, Issue 20; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CERIUM OXIDES
CONCENTRATION RATIO
DEFECTS
DOPED MATERIALS
ELECTRIC POTENTIAL
ELECTROCHEMISTRY
GRAIN BOUNDARIES
IMAGES
MICROSCOPY
NANOSTRUCTURES
PROBES
SAMARIUM
SENSITIVITY
SPATIAL RESOLUTION
THERMAL EXPANSION
VALIDATION