The present invention relates to a lithium-sulfur electrochemical cell comprising as component (A) an electrode comprising lithium metal or lithium alloy, and lithium ion conductively connected thereto as component (B) a glass ceramic membrane comprising an amorphous phase, as component (C) a liquid electrolyte comprising at least one solvent and at least one lithium salt, as component (D) an electrode comprising sulfur as a cathode active species. The present invention also relates to battery comprising a lithium-sulfur electrochemical cell as defined herein. The present invention further relates to the use of a glass ceramic membrane as defined herein as a separator in (i) a lithium-sulfur electrochemical cell, or (ii) a battery comprising at least one lithium-sulfur electrochemical cell.