LaCl3-based sodium halide solid electrolytes with high ionic conductivity for all-solid-state batteries

• Published in: Nature communications Vol. 15; no. 1; p. 4315
• Main Authors: Fu, Chengyu, Li, Yifan, Xu, Wenjie, Feng, Xuyong, Gu, Weijian, Liu, Jue, Deng, Wenwen, Wang, Wei, Abeykoon, A. M. Milinda, Su, Laisuo, Zhu, Lingyun, Wu, Xiaojun, Xiang, Hongfa
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 21.05.2024; Nature Publishing Group UK; Nature Portfolio
• Subjects: Channels; Compressibility; Conductivity; Current density; Diffusion; Electrolytes; Fine structure; First principles; Ion currents; Lanthanum chlorides; Molten salt electrolytes; Sodium; Sodium chromites; Sodium-ion batteries; Solid electrolytes; Solid state; Structural analysis; Ultrastructure; X ray absorption; X-ray diffraction
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-48712-4

Abstract To enable high performance of all solid-state batteries, a catholyte should demonstrate high ionic conductivity, good compressibility and oxidative stability. Here, a LaCl 3 -based Na + superionic conductor (Na 1 − x Zr x La 1 − x Cl 4 ) with high ionic conductivity of 2.9 × 10 −4  S cm −1 (30 °C), good compressibility and high oxidative potential (3.80 V vs . Na 2 Sn) is prepared via solid state reaction combining mechanochemical method. X-ray diffraction reveals a hexagonal structure ( P6 3 /m ) of Na 1 − x Zr x La 1 − x Cl 4 , with Na + ions forming a one-dimensional diffusion channel along the c- axis. First-principle calculations combining with X-ray absorption fine structure characterization etc. reveal that the ionic conductivity of Na 1 − x Zr x La 1 − x Cl 4 is mainly determined by the size of Na + -channels and the Na + /La 3+ mixing in the one-dimensional diffusion channels. When applied as a catholyte, the NaCrO 2 ||Na 0.7 Zr 0.3 La 0.7 Cl 4 ||Na 3 PS 4 ||Na 2 Sn all-solid-state batteries demonstrate an initial capacity of 114 mA h g −1 and 88% retention after 70 cycles at 0.3 C. In addition, a high capacity of 94 mA h g −1 can be maintained at 1 C current density.