Effect of conductivity and frequency on detection of heterogeneities in solid/liquid interfaces using local electrochemical impedance: Theoretical and experimental study

This short communication demonstrates, by solving the Laplace equation with proper boundary conditions (BC) using finite element method (FEM), that it is not possible to establish a correlation between what happens in the electrolyte near an active boundary and what really occurs at the actual boundary if adequate ranges of electrolyte conductivity and input AC signal frequency are not selected, especially when inhomogeneities approximated by Neumann BC are present. Experimental evidence obtained by local electrochemical impedance mapping (LEIM) supports the theoretical results.

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► The detection of irregularities in solid/liquid interfaces has been studied.
► FEM and the Laplace equation with proper boundary conditions were used.
► Adequate ranges of conductivity and input AC signal frequency should be selected.
► Active borders are more affected by the above variables than fixed potential ones.
► Experimental evidences obtained by LEIS mapping support the theoretical results.