Sb‐ and O‐Cosubstituted Li10SnP2S12 with High Electrochemical and Air Stability for All‐Solid‐State Lithium Batteries

Abstract

AbstractThe development of solid‐state electrolytes with high ionic conductivity, broad electrochemical stability, and high air stability is the key to realizing the practical application of all‐solid‐state batteries. Herein, Sb‐ and O‐cosubstituted Li10SnP2S12 sulfide electrolytes are prepared for the first time. An appropriate amount of Sb and O substitution provides the optimized Li10SnP1.84Sb0.16S11.6O0.4 electrolyte with the highest ionic conductivity of 2.58 mS ⋅ cm−1 at RT. Furthermore, the cyclic voltammetry analysis results demonstrate that the Li10SnP1.84Sb0.16S11.6O0.4 electrolyte displays a broader electrochemical window of 1.4–5.0 V vs. Li+/Li than that of 1.7–2.4 V vs. Li+/Li for the nonsubstituted Li10SnP2S12. Moreover, benefitting from the soft acid Sb5+ and hard base O2− dual substitution, the air stability of electrolyte has been improved. Furthermore, the LiNbO3@LiCoO2/Li−In cell assembled with the Li10SnP1.84Sb0.16S11.6O0.4 electrolytes exhibits a high initial discharge specific capacity of 124.7 mAh ⋅ g−1 at 0.05 C and maintains 85 % capacity retention after 200 cycles at 0.5 C and 25 °C, which is much higher than that of the cell assembled with the Li10SnP2S12 electrolytes. XPS measurement results revealed that the mechanism of improving cell stability is the inhibition of electrolyte side reaction in the cathode. Sb‐ and O‐cosubstituted Li10SnP2S12 was demonstrated to be a promising solid electrolyte for practical all‐solid‐state batteries.