In situ generated Li 2 S-LPS composite for all-solid-state lithium-sulfur battery

Li 3 PS 4 (LPS) was in situ formed at the active material Li 2 S through the reaction of Li 2 S and P 2 S 5 by mechanical ball milling, which can be used to composite cathode for Li/S battery. The fine active materials-electrolyte interface will be generated via in situ reaction. Compared with the direct mixing Li 2 S + LPS, the interface impedance between Li 2 S and LPS of Li 2 S-LPS had a significant decrease from 833.3 Ω to 203.7 Ω at room temperature. The effect of heat treatment temperature on the ionic conductivities of Li 2 S-LPS has been studied, and the Li 2 S-LPS-300 showed the highest ionic conductivity of 2.67 × 10 −4 S cm −1 at room temperature. The all-solid-state cell (Li/LPS/Li 2 S-LPS) possessed a larger capacity and better rate performance than that of the cell using Li 2 S + LPS as cathode material, showing a discharge capacity of 624.5 mAh g −1 (g of Li 2 S) for the 20th cycle. We also find that high carbon content of composite cathode will reduce the utilization of Li 2 S. The composite cathode 90Li 2 S-LPS + 10C (wt%) shows the highest capacity of 763.8 mAh g −1 at the current density of 0.1 mA cm −2 .