A novel sodium ion conducting gel polymer electrolyte comprising room temperature ionic liquid, 1-ethyl 3-methyl imidazolium trifluoro-methane sulfonate (EMITf) incorporated with ethylene carbonate and propylene carbonate and its solution with sodium trifluoromethane sulfonate (NaTf) entrapped in poly(vinylidinefluoride-co-hexfluoropropylene) (PVdF-HFP) is prepared using solution cast technique. The gel electrolyte is obtained in the form of free-standing transparent film. The gel electrolyte offers electrical conductivity of ∼10−3Scm−1 at ∼30°C with good mechanical, thermal and electrochemical stability window. The electrical conductivity is measured as a function of temperature and found to be consistent with Vogel-Tamman-Fulcher (VTF) relationship in the temperature range from 30°C to 75°C. Sodium ion conduction in the gel electrolyte film is confirmed from cyclic voltammetry and transport number measurements. The value of the sodium ion transport number of the ionic liquid based gel electrolyte is ∼0.19. The sodium sulfur battery with the gel electrolytes delivers the first discharge capacity of 267mAhg−1 sulfur and then it decreases with repeated charge–discharge cycles. •A novel, free standing Na+ gel electrolyte is reported.•The gel electrolyte offers ionic conductivity ∼10 −3 S cm−1 at 30°C.•Cyclic voltammetry and transport number measurement confirms the Na+ conduction in electrolyte film.•The Na-S battery with the gel electrolyte delivers discharge capacity of 267mAhg−1 sulfur.