Beyond liquid electrolytes, the development of other electrolyte systems is needed to cover all needs for novel batteries suited for detailed usage. Lithium polymer electrolytes for next-generation batteries cover a broad range of emerging energy applications, including their further investigation of solid polymer ionic conductors. Possibility of transferring Li⁺ cations through the unique polymer structure forces modifications of a solid polymer electrolyte. The host matrix is immobile, while long-range cation transport must involve dissociative steps where solvated cations are transferred between neighboring coordination sites, in combination with migration and diffusion of ion aggregates weakly coordinated to the polymer solvent. Most of the current models can be successfully applied to amorphous monophase systems. There are many concepts leading to the increase in flexibility, conductivity performance, and extended storage time for several months, which might be useful for even very demanding battery applications. This review provides readers with a comprehensive background for understanding current knowledge and opportunities for lithium polymer electrolytes.