Fast Li + -conducting Zr 4+ -based oxychloride electrolyte with good thermal and solvent stability

Li 2 ZrCl 6 with a trigonal structure is a low-cost Li + -conducting chloride electrolyte, which is stable at high voltages up to 4.2 V and is compatible with high-voltage cathodes. However, its relatively low room-temperature ionic conductivity, poor stability in different solvents and at high temperatures limit its application for next-generation all-solid-state batteries. Herein, we prepared new oxychloride electrolytes with different molar ratios of Li 2 O, ZrCl 4 , and LiCl, replacing Cl − with O 2− anion to optimize the electrolyte performance. The results showed that increasing the Li 2 O content reduced the crystallization degree of trigonal Li 2 ZrCl 6 and induced a monoclinic structure in the prepared oxychloride electrolyte. The oxychloride with the general formula Li 2.22 Zr 1.11 Cl 5.33 O 0.67 had a high room-temperature ionic conductivity above 10 −3 S cm −1 . Moreover, introducing Li 2 O considerably increased the thermal and solvent stability of the electrolyte. Good ionic conductivity and stability of the electrolyte enable the stable cycling of all-solid-state Li-In/LiCoO 2 batteries.