TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The linear block copolymer is a diblock copolymer. The diblock copolymer is characterized by bicontinuous phases of the conductive polymer block and the structural polymer block. The structural linear polymer block comprises a major phase of the block copolymer. The major phase structural polymer block forms a rigid framework and the conductive polymer block forms nanostructured ionically conductive channels with the rigid framework. The structural polymer has a molecular weight of at least 5000 Daltons. The structural polymer has an elastic modulus of 1x107 Pa to 3 Gpa. The conductive polymer has an elastic modulus of less than or equal to 1 Mpa. The conductive and structural polymers each have molecular weights of at least 15000 (preferably 50000) Daltons. The structural polymer block is ionically non-conductive. The structural polymer block comprises polystyrene, and the conductive polymer block comprises poly(ethylene oxide). The conductive polymer block further comprises a Li salt. The Li salt is concentrated in a central portion of the ionically conductive channels. The ionic conductivity of the block copolymer increases with increasing molecular weight of the conductive polymer block. The ionic conductivity is at least 1x10-4 Scm-1. The bicontinuous phases have a lamellar arrangement. The block copolymer is a triblock copolymer further comprising an additional linear polymer block. The triblock copolymer is a polystyrene-block-polyisoprene-block poly(ethylene oxide) (S-I-EO) triblock copolymer. Preferred Process: The preparation of the polymer electrolyte involves: synthesizing the structural polymer block by living anionic polymerization; adding a monomer of the conductive polymer block and a cryptand catalyst to the structural polymer block living anionic polymerization mixture; allowing a diblock copolymerization reaction to proceed; terminating the reaction; precipitating and freeze-drying the resulting diblock copolymer product; blending the freeze-dried diblock copolymer with the Li salt in a dry solution such that the Li salt is dissolved into the conductive polymer block; and freeze-drying the polymer/salt solution. The process further involves subjecting a portion of the freeze-dried polymer/salt solution to heat and pressure to form a freestanding polymer electrolyte film. The Li salt is LiN(SO2CF3)2. EXAMPLE - No suitable example is given.