The electrochemical properties of mixed-phase composite electrolytes based on poly(ethylene oxide) (PEO), lithium salts (LiClO4, LiBF4, LiPF6, LiCF3SO3, and Li[(CF3SO2)(2)N]), and ferroelectric materials (BaTiO3, PbTiO3, and LiNbO3) have been studied. The ion-conduction and lithium-ion transference numbers of the composite polymer electrolytes were enhanced by the addition of these ferroelectric materials as a ceramic filler. The conductivity behavior of the composite electrolyte depended on the combination of lithium salt and the ferroelectric materials. The conductivity enhancement in the PEO-LiX composite electrolytes with ferroelectric materials was rationalized by correlating the association tendency of anions with lithium cations and the spontaneous polarization of the ferroelectric ceramics due to their particular crystal structure. The combined addition of rutile type TiO2 and BaTiO3 assured long-term interfacial stability. All the electrolytes studied here showed decomposition potentials higher than 4 V vs. Li/Li+