A comprehensive exploration of Na+ ion transport in NaSICONs using molecular dynamics simulations.

Scandium-substituted Na1+x+y Sc y Zr2-y Si x P3-x O12 NaSICONs have emerged as promising electrolyte materials for all-solid-state sodium batteries. However, the comprehensive investigation of these multi-element structures is challenging due to their vast compositional space, leading to a limited number of compositions explored thus far. In this study, we address this issue by employing low-cost, yet high-precision force field molecular dynamics simulations based on density functional theory to investigate the Na+ mobility and resulting conductivity in Na1+x+y Sc y Zr2-y Si x P3-x O12 (0 ≤ x ≤ 3; 0 ≤ y ≤ 2). Our findings show that the incorporation of Sc3+- and Si4+-substituents enhances the conductivity, achieving values of 10-2 S cm-1 at room temperature for moderate to high substitution degrees. Moreover, our study demonstrates the efficacy of the applied methodology for large-scale screening, enabling the exploration of extensive configurational spaces of NaSICONs and other materials for potential use as solid-state electrolytes.