Abstract: A polymer electrolyte comprises a first polymeric matrix, a second polymeric matrix, and a lithium salt. The first polymeric matrix comprises pores. The second polymeric matrix is disposed in at least some of the pores of the first polymeric matrix. The lithium salt is disposed in at least some of the pores of the first polymeric matrix.

Abstract: A composite separator film using polyethylene terephthalate (PET) substrate coated with an organic polymeric film to reduce apertures and pores disposed about the substrate. The organic polymeric film includes an organic polymeric material having high thermal stability and low shrinkage rate. The organic polymeric film can also include a plasticizer to distribute and render the apertures and pores more uniform. The resulting composite separator film can serve to divide the cathode and anode terminals of a lithium-ion battery with enhanced capacity and discharge rate at various current densities and temperatures.