Lengthscale puzzles in concentrated electrolytes
Fluids and Materials Seminar
7th March 2019, 2:00 pm – 3:00 pm
Main Maths Building, SM3
The structure and interactions in electrolytes at high concentration have implications from energy storage to biomolecular interactions and colloidal stability. Recent experiments have shown that the force between charged surfaces across concentrated electrolytes has a short-ranged, oscillatory component superimposed onto a long-ranged exponentially decaying component. The length scale of the short-ranged oscillations, as well as the long-ranged decay, both depend intricately on ion concentration, and are completely at odds with the conventional wisdom given by classical mean-field Poisson-Boltzmann theory. In my talk, I will attempt to explain those lengthscale puzzles using a combination of classical density functional theory and a scaling analysis. Our results shed light on the mechanism of energy storage in electrical double layer supercapacitors, as well as the activity coefficient in electrolytes.