Porous polymer films and plasticised polymer films of vinylidene fluoride (VDF)-hexafluoropropylene (HFP)-chlorotrifluoroethylene (CTFE) terpolymers have been fabricated from a range of solvents. Significant 2EC/PC solvent uptake was measured at 60 degreesC for VDF-HFP-CTFE terpolymer films but structural integrity was maintained.0.625 Ah soft packaged graphite-LiCoO2 test cells have been fabricated containing porous VDF-HFP-CTFE terpolymer films as separator. Ninety-eight percent of Rated Capacity was measured at 2C rate. Four hundred and fifty-four cycles were obtained at C rate to 80% of Rated Capacity. Thin 4-5 mum plasticised VDF-HFP-CTFE terpolymer films have also been produced. (C) 2003 Elsevier Science B.V. All rights reserved.