Cost-Effective and High Ionic Conductivity Sulfide Solid Electrolyte Li_7.3P_2.9S_10.75X_0.3 (X = F, Cl, Br, and I) for All-Solid-State Lithium Batteries

High Resolution Image Download MS PowerPoint Slide Sulfide solid electrolytes (SSEs) have some huge advantages in high room-temperature conductivity, good thermal stability, low interfacial resistance, etc. They are one of the ideal solid electrolytes for developing high energy density and high safety for all-solid-state lithium batteries (ASSLBs). However, the preparation of SSEs requires expensive Li 2 S as the raw material, whose high cost limits its practical application. Herein, a cost-effective SSE Li 7.3 P 2.9 S 10.75 X 0.3 (X = F, Cl, Br, and I) was designed and prepared by using low-cost lithium and sulfur instead of expensive Li 2 S. Significantly, the cost of SSEs was reduced from $169.72 to $28.13 kg –1 based on replacing the Li 2 S strategy. Moreover, the prepared Li 7.3 P 2.9 S 10.75 X 0.3 (X = F, Cl, Br, and I) solid electrolytes have a high ionic conductivity of 1.86–2.73 mS cm –1 at room temperature and a high voltage window of 5 V. On this basis, we assembled the all-solid-state lithium battery TiS 2 /Li 7.3 P 2.9 S 10.75 I 0.3 /Li–In, which presented a high initial discharge capacity of 219 mA h g –1 at room temperature and satisfactory cycle stability with a capacity retention of 86.7% after 100 cycles at 0.50 mA cm –2 . This work provides an effective strategy for reducing the cost of SSEs, advancing the practical process of ASSLBs.