In this study, we report the first use of a "high salt concentration ionic liquid" electrolyte with high molecular weight PEO to form high-performance solid polymer electrolytes, and their application in all-solid-state lithium metal batteries. These designed electrolytes are featured with unique interconnected and locally aligned ion clusters and pores that provide extra Li + ion transport pathways, leading to both high room temperature ionic conductivity and wide ESW. Benefiting from the organized structure change and increased ion dynamics by adding concentrated IL, ionic conductivity of 5.6 x10 -4 S cm -1 at 30°C is achieved with the optimal composition. Further FTIR and solid-state MAS NMR investigations confirm that these promising behaviors can be ascribed to a Li + environment change including increased Li + -FSI -interactions and weakened Li + -EO interactions, leading to the formation of interconnected ion clusters as a distinct phase. The coordinated ions and surrounded ion clusters protect EO from oxidation, leading to improved oxidation stability (5.1 V). The novel PiHCIL-SPE provide stable Li symmetric cycling and promising electrochemical performance with a composite LFP cathode using the designed PiHCIL-SPE as the binder material, reflecting the superiority of the "PEO-in-HCIL" strategy. The implications of this research bring a new understanding of PEO-based SPEs, promising not only to advance the field of all-solid-state LMBs but also to contribute to the broader pursuit of sustainable and high-performance energy storage solutions.