Oxygen Ion Conduction Property of Solid Oxide Membrane Based on Multi-scale Analysis

Abstract

There have been reports of decreased ion transport properties at the grain boundaries (GB). Multiscale analysis is necessary to analyze the relationship between small-scale phenomena near the GB and large-scale ion transport properties across the membrane. We perform bottom-up analysis from Density Functional Theory (DFT) to kinetic Monte Carlo methods. In this study, we analyzed the effect of GB on ion transport properties using DFT-based molecular dynamics (MD) simulation. The following results were obtained by changing the number of SrSc0.1Co0.9O3-δ (SSC) and Sm0.2Ce0.8O2-δ (SDC) unit cells in the dual-phase solid oxide electrolyte membrane (SOEM). As the crystal size of SSC increased, both the diffusion coefficient and activation energy increased. As the crystal size of SDC increased, the diffusion coefficient decreased, and the activation energy increased. Furthermore, the calculated diffusivity of the x, y, and z directions show that the diffusivity was decreasing in the direction of the GB exist.