3. Classification of polymer electrolytes and their limits

The first dry solid polymer electrolytes (EPS) were obtained from lithium salts, such as LiClO ₄ or LiBF ₄ , and the high-molecular-weight poly(oxyethylene) POE . In such systems, no liquid organic solvent is used; the host polymer acts as a solid solvent. POE contains ether coordination sites that enable salt dissociation, as well as a flexible macromolecular structure that promotes ionic transport. Nevertheless, the presence of crystalline zones in POE interferes with ion transport, which requires an amorphous phase. This affects ionic conductivity at temperatures below the melting point of POE, around 65°C....