Understanding the influence of local structure distortions on Na-ion migration in perovskite solid electrolytes

The perovskite structured oxides of composition ABO₃ are considered strong candidates for solid-state electrolytes in all-solid-state batteries due to their chemical and structural flexibility. However, further improvements must be made before they become commercially viable, and this requires a clear understanding of the structure-property relationships. In this study, the local structure of the perovskite sodium-ion solid electrolyte series Na_1/2−xLa_1/2−xSr_2xZrO₃ (NLSZ, x = [Formula presented], [Formula presented], [Formula presented], [Formula presented]) was investigated via neutron total scattering. Small-box modelling against the neutron pair distribution function with the orthorhombic Pbnm structure showed local-scale features that deviate from the average structure. Big-box modelling revealed significant differences between the bonding configurations of the different A-site cations, which impacts the ionic conductivity of the material. This study demonstrates how understanding local-scale disorder is important for tuning the structure-property relationships of inorganic solid-state electrolyte materials in sustainable battery technologies.