Encapsulating and Operating a Stable Li3ErBr6-Based Solid Li-SeS2 Battery at Room Temperature

Rare earth-based halide solid electrolytes (RE-HSEs) are noted due to their comprehensive properties of good ionic conductivity, electrochemical window, and deformability. However, the types and applications of RE-HSEs need to be further expanded. Here, a highly purified RE-HSE Li3ErBr6 (LErB) is synthesized successfully by a vacuum evaporation method. The prepared LErB possesses a high ionic conductivity of 1.0 mS cm(-1) with an electrochemical window of 1.5-3.4 V. The LErB is applied in a solid Li-SeS2 battery, which can realize stable cycling performance for 300 cycles and good rate performance at room temperature. Moreover, to evaluate the practicability of the LErB-based Li-SeS2 battery, a pouch-type cell is assembled, which can light a diode array even after bending and cutting. These results demonstrate that LErB-based solid Li-SeS2 cells possess advantages in battery packaging and operation, which can improve the practicability of all-solid-state lithium batteries.