Crystalline Li-Ta-Oxychlorides with Lithium Superionic Conduction

Nowadays, some amorphous and microcrystalline solid-state electrolytes (SSEs) with dual anions have attained high ionic conductivity and good compatibility with electrodes in all-solid-state lithium-ion batteries (ASSLIBs). In this work, crystalline SSEs of series A (Li1+xTaO1+xCl4−x, −0.70 ≤ x ≤ 0.50) and B (LiTaO2+yCl2−2y, −1.22 ≤ y ≤ 0), having great application potential well over ambient temperatures, were prepared at 260–460 °C for 2–10 h using Li2O, TaCl5, and LiTaO3 as the raw materials. The three-phase coexisting samples attained high σ values ranging from 5.20 to 7.35 mS cm−1, which are among the reported high values of amorphous co-essential SSEs and other alloplasmatic crystalline ones. It is attributed to the synergistic effect of the polyanion trans-[O2Cl4] and cis-[O4Cl2] octahedra framework.