All-solid-state electrochemical cells and batteries employing very thin film, highly conductive polymeric electrolyte and very thin electrode structures are disclosed, along with economical and high-speed methods of manufacturing. A preferred embodiment is a rechargeable lithium polymer electrolyte battery. New polymeric electrolytes employed in the devices are strong yet flexible, dry and non-tacky. The new, thinner electrode structures have strength and flexibility characteristics very much like thin film capacitor dielectric material that can be tightly wound in the making of a capacitor. A wide range of polymers, or polymer blends, characterized by high ionic conductivity at room temperature, and below, are used as the polymer base material for making the solid polymer electrolytes. The preferred polymeric electrolyte is a cationic conductor. In addition to the polymer base material, the polymer electrolyte compositions exhibit a conductivity greater than 1.times.10.sup.-4 S/cm at 25.degree. C. or below and contain an electrically conductive polymer, a metal salt, a finely divided ionic conductor, and a finely divided inorganic filler material. Certain rechargeable batteries of the invention provide high specific energy (250 to 350 Wh/kg) (gravimetric) and energy density (450 to 550 Wh/l) (volumetric), high cycle life (1000 cycles), low self-discharge and improved safety.