On the influence of the coherence length on the ionic conductivity in mechanochemically synthesized sodium-conducting halides, NaInZrCl

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2024-03, Vol.12 (12), p.715-724
• Main Authors: Zhao, Tong, Sobolev, Alexander N, Martinez de Irujo Labalde, Xabier, Kraft, Marvin A, Zeier, Wolfgang G
• Format: Article
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d3ta07209f

The Na + ionic conductivity of ball milled Na 3− x In 1− x Zr x Cl 6 rises with increasing Zr content, while that in the subsequently annealed Na 3− x In 1− x Zr x Cl 6 compounds reaches a maximum conductivity at an intermediate substitution degree ( x = 0.5). To clarify the underlying mechanism causing the differing trends, the local structure and coherence length of the ball milled Na 3− x In 1− x Zr x Cl 6 solid solutions were investigated by pair distribution function analyses. The structural evolution in the ball milled Na 3− x In 1− x Zr x Cl 6 series resembles those found in their annealed counterpart, however, its structural coherence length decreases with higher Zr content. By further investigating the transport properties using impedance spectroscopy, this work uncovers a correlation between the coherence length and the ionic conductivity in ball milled Na 3− x In 1− x Zr x Cl 6 , in which lower structural coherence leads to higher ionic transport. This work indicates an influence of the microstructure beyond unit cell scale onto macroscopic transport properties in these sodium-conducting halide solid electrolytes. A decreasing coherence length with higher Zr content in ball milled Na 3− x In 1− x Zr x Cl 6 is observed, which leads to a negative correlation between the ionic conductivity and the material's coherence length.