# Electrolyte solutions at curved electrodes. II. Microscopic approach

## TL;DR

This paper employs density functional theory to analyze the microscopic structure of electrolyte solutions near curved electrodes, revealing how particle size and surface charge influence the electric double layer and capacitance.

## Contribution

It introduces a microscopic approach using the civilized model to study electrolyte-electrode interactions, extending beyond mesoscopic models and highlighting the impact of microscopic details.

## Key findings

- Small electrode radii lead to charge-independent results.
- Large radii show significant effects of particle size and surface charge.
- Electrode shape determines the necessity of detailed microscopic modeling.

## Abstract

Density functional theory is used to describe electrolyte solutions in contact with electrodes of planar or spherical shape. For the electrolyte solutions we consider the so-called civilized model, in which all species present are treated on equal footing. This allows us to discuss the features of the electric double layer in terms of the differential capacitance. The model provides insight into the microscopic structure of the electric double layer, which goes beyond the mesoscopic approach studied in the accompanying paper. This enables us to judge the relevance of microscopic details, such as the radii of the particles forming the electrolyte solutions or the dipolar character of the solvent particles, and to compare the predictions of various models. Similar to the preceding paper, a general behavior is observed for small radii of the electrode in that in this limit the results become independent of the surface charge density and of the particle radii. However, for large electrode radii non-trivial behaviors are observed. Especially the particle radii and the surface charge density strongly influence the capacitance. From the comparison with the Poisson-Boltzmann approach it becomes apparent that the shape of the electrode determines whether the microscopic details of the full civilized model have to be taken into account or whether already simpler models yield acceptable predictions.