Overscreening and Underscreening in Solid-Electrolyte Grain Boundary Space-Charge Layers
Abstract
Polycrystalline solids can exhibit material properties that differ significantly from those of equivalent single-crystal samples, in part, because of a spontaneous redistribution of mobile point defects into so-called space-charge regions adjacent to grain boundaries. The general analytical form of these space-charge regions is known only in the dilute limit, where defect-defect correlations can be neglected. Using kinetic Monte Carlo simulations of a three-dimensional Coulomb lattice gas, we show that grain-boundary space-charge regions in non-dilute solid electrolytes exhibit overscreening -- damped oscillatory space-charge profiles -- and underscreening -- decay lengths that are longer than the corresponding Debye length and that increase with increasing defect-defect interaction strength. Overscreening and underscreening are known phenomena in concentrated liquid electrolytes, and the observation of functionally analogous behaviour in solid electrolyte space-charge regions suggests that the same underlying physics drives behaviour in both classes of systems. We therefore expect theoretical approaches developed to study non-dilute liquid electrolytes to be equally applicable to future studies of solid electrolytes.
Cite
@article{arxiv.2104.00623,
title = {Overscreening and Underscreening in Solid-Electrolyte Grain Boundary Space-Charge Layers},
author = {Jacob M. Dean and Samuel W. Coles and William R. Saunders and Andrew R. McCluskey and Matthew J. Wolf and Alison B. Walker and Benjamin J. Morgan},
journal= {arXiv preprint arXiv:2104.00623},
year = {2021}
}