New Insight for Solid Sulfide Electrolytes LSiPSI by Using Si/P/S as the Raw Materials and I Doping

Solid sulfide electrolyte has been researched for several years, and a high ionic conductivity has been acquired. However, it is difficult to apply in industrial manufacturing partly because the raw materials, such as SiS2, GeS2, P2S5, et al., have strict preparing conditions and are sensitive to water and oxygen in the air. Herein, we report a new method to produce solid sulfide electrolytes Li9.54Si1.74P1.44S11.7X0.3 (LSiPSX) (X = F, Cl, Br, I), that is, using elementary substances Si, P, and S as the starting raw materials, which not only is a promising way to ease the harsh storage conditions of the SiS2 and P2S5 as starting raw materials but also provides a feasible choice for the preparation of solid sulfide electrolyte. The conductivity of solid sulfide electrolyte is further adjusted by controlling the particle size of raw material silicon and the different halogen doping. As a result, the Li9.54Si1.74P1.44S11.7I0.3 releases the highest ionic conductivity of 1.35 mS/cm at room temperature and a wide electrochemical window up to 9 V versus Li/Li+ which is prepared from the 3 nm particle size Si and I doping. The all-solid-state lithium–sulfur battery (ASSLSB) is constructed with LSiPSI and with a good performance. Our study demonstrates the possibility of preparing the LGPS crystal type solid sulfide electrolytes by using elementary substances.