Quantitative Analysis of Topographic Crosstalk in DART‐ESM Arising from Feedback‐Loop‐Delay‐Induced Contact Stiffness Variations in Battery Materials

Electrochemical Strain Microscopy (ESM) is widely used to probe nanoscale ion dynamics in battery materials, particularly at grain boundaries, where ionic transport is often proposed to be localized. However, interpretation of ESM signals remains challenging because topography‐induced artifacts can artificially enhance the measured response. Here, topographic crosstalk arising from contact stiffness variation induced by feedback‐loop delay is quantitatively analyzed in Dual AC Resonance Tracking (DART)‐ESM using ionically inactive single‐crystal silicon as a reference material. Artificial trench structures are introduced to emulate grain‐boundary‐like topography commonly encountered in battery electrodes and solid electrolytes. Simple harmonic oscillator (SHO) analysis of contact‐resonance dynamics shows that ESM amplitude enhancement can arise from contact stiffness variations independent of ionic motion. These silicon‐based measurements provide a practical reference for identifying topographic crosstalk and estimating its magnitude. Reproducibility is confirmed across multiple silicon calibration samples and further validated in practical battery materials, including a graphite anode and a Na 2 Zn 2 TeO 6 (NZTO) solid electrolyte, indicating that such artifacts are inherent to DART‐ESM under practical measurement conditions. Cooling Cross‐Section Polishing (CCP) effectively suppresses these artifacts by reducing surface roughness and stabilizing contact resonance. These results provide a practical framework for reliable interpretation of nanoscale electrochemical activity in battery materials.