Electrolytes structure near electrodes with molecular size roughness

TL;DR

This paper presents a model describing how electrode surface roughness at the molecular scale affects electrolyte structure and capacitance, offering insights for optimizing supercapacitor performance.

Contribution

A novel model linking electrode surface roughness to electrolyte ion distribution and capacitance behavior, surpassing flat-electrode theories.

Findings

Increased electrostatic field near rough surfaces enhances ion separation.

Capacitance exhibits sharper dependence on applied potential due to surface roughness.

Model aligns with observed simulation results of electrolyte behavior.

Abstract

Understanding the electrodes' surface morphology influence on the ions' distribution is essential for designing the supercapacitors with enhanced energy density characteristics. We develop a model for the structure of electrolytes near the rough surface of electrodes. The model describes an effective electrostatic field's increase and associated intensification of ions' spatial separation at the electrode-electrolyte interface. These adsorption-induced local electric and structure properties result in notably increased values and sharpened form of the DC dependence on the applied potential. Such capacitance behavior is observed in many published simulations, and its description is beyond the capabilities of the established flat-electrodes theories. The proposed approach could extend the quantitatively verified models providing a new instrument of the electrodes surface-parameters optimization for specific electrolytes.