One of the major drawbacks of lithium/sulfur (Li/S) batteries is the dissolution of polysulfides into liquid electrolytes. In order to overcome this difficulty, polymer/silicate nanocomposite electrolytes composed of polyvinylidene fluoride-co-hexafluoropropylene (PVdF-HFP) and different types of nano-layered silicates were fabricated and analyzed. All the electrolyte membranes showed ionic conductivity of 5-7 mS/cm at room temperature and electrochemical stability window up to 4.8 V. Tested by two different sulfur composite cathodes, PVdF-HFP/organically-modified-silicate (OMMT) nanocomposite electrolyte delivered a higher discharge capacity and showed an improved cyclability compared to the other cells. Such electrochemical performance is attributed to the small and uniformly distributed pores within the structure of the polymer nanocomposite membrane, which promotes immobilizing the electrolyte solution and prevents dissolution of polysulfides. (C) 2013 The Electrochemical Society. All rights reserved.