The Impact of Concentration and Electric-Field Dependent Susceptibilities on Electrolyte Models

Abstract

Electrolytes have a significant role in a range of scientific and technological fields such as fundamental electrochemistry, biochemical systems, semiconductors, and industrial devices. A widely used mathematical framework for describing electrolytes is based on Poisson-Nernst-Planck-type equations and their successors[1], but the Poisson equation assumes a constant dielectric susceptibility. However, recent research has developed a thermodynamically consistent model for the dielectric susceptibility that accounts for its dependence on both concentration and electric field [5,6]. This allows for the inclusion of the dependency of the susceptibility on salt concentration in liquid electrolytes, referred to as dielectric decrement[2,3,4], as well as the decline in susceptibility for large electric fields[8], known as dielectric saturation.The research findings highlight the importance of considering the variable dielectric susceptibility in electrolyte models, particularly in relation to the decrease in dielectric permittivity in front of a charged electrode surface[7]. The study demonstrates the impact of the concentration and electric-field-dependent susceptibility on the overall equation system for electrochemical double layers. By providing insights into the theoretical aspects of the approach, the researchers aim to contribute to the development of more accurate and comprehensive models of electrolytes that consider the complex interplay of various factors.