SULFIDE-BASED SOLID ELECTROLYTE AND ALL-SOLID-STATE LITHIUM ION BATTERY

Provided are sulfide-based solid electrolyte with good ionic conductivity and an all-solid lithium ion battery using the same. A sulfide-based solid electrolyte having an argyrodite-type structure, wherein a composition of the sulfide-based solid electrolyte is represented by the formula: LiGeSTe in which: -0.5 ≤ x < 0, 0 < x ≤ 0.375.