Search

Monoclinic natrium superionic conductors (NASICON; Na3Zr2Si2PO12) are well‐known Na‐ion solid electrolytes which have been studied for 40 years. However, due to the low symmetry of the crystal structure, identifying the migration channels of monoclinic NASICON accurately still remains unsolved. Here, a cross‐verified study of Na+ diffusion pathways in monoclinic NASICON by integrating geometric analysis of channels and bottlenecks, bond‐valence energy landscapes analysis, and ab initio molecular dynamics simulations is presented. The diffusion limiting bottlenecks, the anisotropy of conductivity, and the time and temperature dependence of Na+ distribution over the channels are characterized and strategies for improving both bulk and total conductivity of monoclinic NASICON‐type solid electrolytes are proposed. This set of hierarchical ion‐transport algorithms not only shows the efficiency and practicality in revealing the ion transport behavior in monoclinic NASICON‐type materials but also provides guidelines for optimizing their conductive properties that can be readily extended to other solid electrolytes. [ABSTRACT FROM AUTHOR]

High-throughput analysis of the ion transport pathways is critical for screening fast ion conductors. Currently, empirical methods, such as the geometric analysis and bond valence site energy (BVSE) methods, are respectively used for the task. Geometric analysis method can only extract geometric and topological pathway properties without considering the interatomic interactions, while the BVSE method alone does not yield a geometric classification of the sites and interstices forming the pathway. Herein, we propose a highly efficient and informative method to identify interstices and connecting segments constructing an ion transport network by combining topological pathway network and BVSE landscape, which enables to obtain both the geometry and energy profiles of nonequivalent ion transport pathways between adjacent lattice sites. These pathways can be further used as the input for first-principles nudged elastic band calculations with automatically generated chains of images. By performing high-throughput screening of 48,321 Li-, Na-, Mg- and Al-containing ionic compounds from the Inorganic Crystal Structure Database based on the filter combining geometric analysis and BVSE methods, we obtain 1,270 compounds with connected ionic migration pathways of suitable sizes and low migration energy barriers, which include both previously reported fast ion conductors, and new promising materials to be explored further. Image, graphical abstract [ABSTRACT FROM AUTHOR]