Fast Lithium Ionic Conductivity in Complex Hydride-Sulfide Electrolytes by Double Anions Substitution

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)-xP(2)S(5) (LLPx, 0 <= x <= 50). Among these samples, LLP20 respectively delivers an ionic conductivity up to 3.77 x 10(-4) S cm(-1) at 30 degrees C and 1.0 x 10(-2) S cm(-1) at 100 degrees 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.

Automated summary

The study explores a fast lithium-ion conductor LLPL20 at room temperature, which exhibits relatively high ionic conductivity and good stability at 30 degrees Celsius, providing a practical strategy for the development of all solid-state batteries.