Bulk solid electrolyte-enabled solid-state lithium batteries with high energy density and better safety features are proposed to revolutionize battery-operated electric vehicles and other defense appliances. However, poor contact, high interfacial resistance, and inhomogeneous metallic lithium growth are the severe concerns associated with inorganic solid electrolytes. In this regard, solid polymer electrolytes are promising options for solid-state lithium batteries. Although ion-conducting ceramic incorporation has long been sought for polymer reinforcement, their discontinuous and inhomogeneous distribution inside the polymer network hinders ionic transportation. Further, the excess use of such ionic conducting additives reduces the overall mechanical and thermal properties, which in turn results in the poor performance of lithium batteries. Therefore, an advanced interlayer nano engineering is utmost required for improved charge kinetics at electrode/electrolyte interface for high performing and safer Li battery technology.