In this paper the characteristics and performance of composite polymer electrolytes formed by dispersing selected ceramic (e.g. γ-LiAlO2, Al2O3, SiO2) powders in poly(ethylene oxide)–lithium salt (e.g. PEO–LiCF3SO3) matrices, are reported and discussed. Particular emphasis is devoted to the role of these composite electrolytes in providing the conditions for stabilizing the interface with the lithium metal electrode, as well as for enhancing the electrolyte’s overall transport properties. Finally, results based on tests of practical prototypes demonstrate that these unique properties allow the development of new types of high performance, rechargeable lithium polymer batteries.