Overview
- KAIST announced on Monday that a Small Methods paper demonstrates Electrochemical Strain Microscopy (ESM) can show false ion‑movement signals when surface roughness changes the probe’s contact with a sample.
- The team traced the artifact to variations in tip‑sample contact stiffness combined with delays in Dual AC Resonance Tracking (DART‑ESM) feedback, which turn mechanical contact changes into electrical signals that mimic ion flow.
- Researchers proved the effect by etching fine trenches in ionically inactive single‑crystal silicon and still observing ESM signals, and then confirmed the same topographic crosstalk on real battery materials including graphite anodes and Na2Zn2TeO6.
- As a practical fix, the group used Cooling Cross‑Section Polishing (CCP) with an inert argon ion beam to flatten cross‑sections; polished surfaces no longer showed the enhanced grain‑boundary signals that had been taken as fast‑ion pathways.
- The findings mean past ESM maps that flagged grain boundaries as fast‑ion routes may need re‑evaluation and offer a way to produce cleaner nanoscale data for battery development and machine‑learning models that predict material performance.