Fast Lithium Ionic Conductivity in Complex Hydride‐Sulfide Electrolytes by Double Anions Substitution
Tengfei Zhang, Yifei Shao, Xiang Zhang, Yuqin Huang, Shuai Wang, Wei Zhou, Peng Li, Guanglin Xia, Xuebin Yu
Abstract
Abstract Hydride‐based solid‐state electrolytes (SSEs) can maintain their stability against Li metal and exhibit high compatibility with a Li metal anode owing to their reducing property and flexible character. However, poor ionic conductivity at room temperature is a major challenge for hydride materials used as SSEs in a lithium ion battery. In this work, a room‐temperature fast lithium‐ion conductor is explored in response to double anion substitution, (100‐ x )(3LiBH 4 ‐LiI)‐ x P 2 S 5 (LLP x , 0 ≤ x ≤ 50). Among these samples, LLP20 respectively delivers an ionic conductivity up to 3.77 × 10 −4 S cm −1 at 30 °C and 1.0 × 10 −2 S cm −1 at 100 °C, with a stable electrochemical window of 0–5 V. A Li plating/stripping test has been conducted under a current density of 1.0 mA cm −2 , which exhibits an excellent stability even after 1000 h. Moreover, the all solid‐state cell exhibits a remarkable electrochemical performance in a wide temperature range including high reversible capacity, good rate capability, and long cycling durability. These outstanding performances present a practical strategy for developing ambient‐temperature, fast ionic conductors for all solid‐state batteries in near future.