Electrochemistry at conductor/insulator/electrolyte three-phase interlines: A thin layer model

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Electrochemical conversion of insulators to conductors is crucial for various applications.
• Understanding the interface dynamics at the conductor/insulator/electrolyte three-phase interline (3PI) is essential.
• Mass diffusion effects in the electrolyte can complicate conversion processes.

Purpose of the Study:

• To develop a thin layer model for insulator-to-conductor electrochemical conversion at the 3PI.
• To analyze the influence of negligible mass diffusion on the conversion process.
• To validate the model with experimental data and derive kinetic parameters.

Main Methods:

• Development of a thin layer electrochemical model.
• Potentiostatic condition application to predict current and 3PI length variations.
• Experimental validation using electroreduction of AgCl and SiO2.
• Derivation of kinetic parameters, including the electron transfer coefficient (alpha).

Main Results:

• The model predicts a linear relationship between current or 3PI length and time under potentiostatic conditions.
• A linear increase of current/time or 3PI-length/time ratio with applied potential was observed for large polarizations.
• Experimental data for AgCl and SiO2 electroreduction closely matched model predictions.
• Kinetic parameters were successfully derived, with alpha values of ~0.29 for AgCl and ~10(-2) for SiO2.

Conclusions:

• The proposed thin layer model effectively describes insulator-to-conductor electrochemical conversion at the 3PI.
• The model provides a valuable tool for understanding and predicting electrochemical processes at interfaces.
• The derived kinetic parameters offer insights into the specific reduction mechanisms of AgCl and SiO2.