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arXiv · 1305.5416

New Methods for Calculating the Free Energy of Charged Defects in Solid Electrolytes

Robert M. Horton·Andrew J. Haslam·Amparo Galindo·George Jackson·Michael W. Finnis
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Abstract

A methodology for calculating the contribution of charged defects to the configurational free energy of an ionic crystal is introduced. The temperature-independent Wang-Landau Monte Carlo technique is applied to a simple model of a solid electrolyte, consisting of charged positive and negative defects on a lattice. The electrostatic energy is computed on lattices with periodic boundary conditions, and used to calculate the density of states and statistical-thermodynamic potentials of this system. The free energy as a function of defect concentration and temperature is accurately described by a regular solution model up to concentrations of 10% of defects, well beyond the range described by the ideal solution theory. The approach, supplemented by short-ranged terms in the energy, is proposed as an alternative to free-energy methods that require a number of simulations to be carried out over a range of temperatures.

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Robert M. Horton, Andrew J. Haslam, Amparo Galindo, George Jackson, Michael W. Finnis. 2013-05-23. New Methods for Calculating the Free Energy of Charged Defects in Solid Electrolytes. https://doi.org/10.1088/0953-8984%2F25%2F39%2F395001

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