Enhanced Ionic Conductivity and Air Stability of Bi2se3-Doped 80li2s-20p2s5 Solid-State Electrolytes

Excellent ionic conductivity and electronic insulation are core properties of solid electrolytes. In this study, we use high-energy ball milling and high-temperature sintering heat treatment to prepare a solid electrolyte, i.e., 80Li 2 S-20P 2 S 5 (LPS), with an Li 2 S crystal state; P 2 S 7 4- and PS 4 3- high-conductive glass phases can be observed inside, and its ionic conductivity (1.52 × 10 -4 Scm -1 ) is comparable with that of Li 2 P 8 S 9 in the glass-ceramic state. On this basis, we modify the prepared LPS solid-state electrolyte through Bi 2 Se 3 doping. First-principles computations based on density flooding theory indicate that Bi 2 Se 3 doping can broaden lithium-ion transport channels and increase the lithium-ion conduction rate. With a doping ratio of 4%, the ion conductivity reaches 3.01 × 10 -3 Scm -1 , which offers good insulation to electrons and a stable [[EQUATION]] –5 V (vs. Li/Li + ) high-voltage platform. Bi 2 Se 3 doping greatly improves the air stability of the LPS solid electrolyte; its adsorption energy to water is reduced in absolute value, and the bridging S is not easily replaced by O in H 2 O. Our research provides a new approach for the development of sulfur-based solid electrolytes and lithium–sulfur battery storage.