A novel polymer membrane comprising poly(vinylidene difluoride hexafluoropropylene) (PVdF-HFP) copolymer was prepared by phase inversion technique with two different nonsolvents. The membranes were gelled in an electrolyte solution of 1 M of LiPF6 in EC/DMC and were subjected to a.c. impedance analysis at temperatures ranging from - 30 to 70 degreesC. The films were characterized by SEM, adsorption/desorption, NMR spectroscopy and charge-discharge studies. The morphology, pore diameter, pore volume, and the ionic conductivity of the films varied greatly with the nonsolvent. The diffusion coefficients of Li-7 and F-19 ionic species were separately identified using the pulsed-field gradient NMR (PFG-NMR) and the results are discussed. The morphology and other physical properties of the films are correlated with the structure of the nonsolvent used.