Page 38 - Read Online

Li et al. J. Mater. Inf. 2025, 5, 21 https://dx.doi.org/10.20517/jmi.2024.87 Page 3 of 15

Figure 1. Workflow for screening promising potassium-ion conductors.

MATERIALS AND METHODS
GT approach
The cationic conductivity of inorganic compounds is largely governed by the presence of a continuous
network of channels and voids within the crystal structure, which facilitate cation migration. In the Voronoi
partition approach, the crystal space is divided into two dual subspaces: atoms and voids. To analyze cation
migration pathways, the vertices and edges of Voronoi polyhedra are treated as elementary voids and
channels, based on key criteria derived from known solid electrolytes. The construction of the graph and
polyhedral representations of the void space, as well as the subsequent analysis of their GT characteristics, is
[42]
implemented in the ToposPro software package . This GT approach has been successfully applied to
+[44]
+[43]
predict suitable cathode and electrolyte materials for various cations, including Li , Na , and Zn 2+[45] .
To assess the geometric criteria for cation migration, we computed the radii of the elementary channels
(r ) and compared them with the minimum threshold value, r (min) = γ(r(K) + r(P)), where r(K) and r
chan
chan
(P) represent the Slater radii of K and P, respectively . The deformation coefficient γ is a function of the
[46]
characteristics of the mobile cations and framework anions. For this study, we used γ = 0.8, reflecting the
large radius and high charge of the P anion, and adopted r (min) = 2.5 Å as the minimal channel radius
3-
chan
sufficient for potassium migration . Additionally, we excluded channels that were solely surrounded by
[47]
cations, regardless of their size, to investigate their impact on the overall conductivity pattern.
BVSE calculations
[48]
The BVSE approach , implemented in the GUI version of the softBV program [49,50] , has become a widely
adopted tool in crystal chemistry for investigating ionic migration pathways. This method is based on the