3D porous PTFE membrane filled with PEO-based electrolyte for all solid-state lithium–sulfur batteries

Owing to the low cost and high theoretical energy density, lithium–sulfur battery has become one of the most promising energy storage battery systems. However, the inherent cycle instability and safety problems of traditional liquid lithium–sulfur batteries greatly limit their commercial applications. In this work, polytetrafluoroethylene (PTFE) membrane was introduced into Li₇La₃Zr₂O₁₂ (LLZO)@poly(ethylene oxide) (PEO)-based composite electrolyte as a supporting framework to prepare a new PTFE@LLZO@PEO composite electrolyte for lithium–sulfur battery. The introduction of PTFE membrane further improved the mechanical properties and thermal stability of the electrolyte. The ionic conductivity of the prepared PTFE@LLZO@PEO solid electrolyte was 5.03 × 10⁻⁵ S·cm⁻¹ at 30 °C and 2.54 × 10⁻⁴ S·cm⁻¹ at 60 °C. Moreover, the symmetric battery exhibited high cycle stability (300 h). The Li–S battery based on PTFE@LLZO@PEO electrolyte exhibited excellent electrochemical performance.