Related Experiment Video
Updated: Jun 16, 2026

In Situ Neutron Powder Diffraction Using Custom-made Lithium-ion Batteries
Published on: November 10, 2014
Charge reversal of surfaces in divalent electrolytes: the role of ionic dispersion interactions
Drew F Parsons1, Barry W Ninham
1Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT 0200, Australia.
Abstract:
Surface potentials of alkali earth nitrates at a mica surface are calculated using a modified Poisson-Boltzmann approach that includes nonelectrostatic ion-surface dispersion interactions. New ab initio dynamic polarizabilities are used to determine dispersion interactions. A hydration model describing the hydration shell of cations is presented. Excellent agreement with experiment is achieved, including charge reversal at high electrolyte concentration without the need for site binding models. This suggests that specific ionic dispersion forces provide the mechanism for ion surface binding. An asymptotic surface potential is found in the limit of very high concentration. A Hofmeister series is predicted according to the strength of charge reversal, with Mg > Ca > Sr > Ba. The ion-surface dispersion adsorption energies of hydrated ions appear to explain the apparent repulsive secondary hydration forces observed experimentally between mica surfaces when taken with a surface hydration layer.
Related Concept Videos
Electrochemical Systems
Intermolecular Forces
Electrolytes: van't Hoff Factor
The Electrical Double Layer
Ionic Association
Theory of Strong Electrolytes

