The interfacial incompatibility of the poly (ethylene oxide)-based electrolytes hinder the longevity and further practice of all-solid-state batteries. Herein, we present a productive additive 1-Fluoroadamantane facilitating to the distinct performance of the poly (ethylene oxide)-based electrolytes. Attributed to the strong molecular interaction, the coordination of the Li⁺-EO is reduced and the ‘bonding effect’ of anion is improved. Thus, the Li ⁺ conductivity is promoted and the electrochemical window is widened. The diamond building block C₁₀H₁₅^– strengthens the stability of the solid polymer electrolytes. Importantly, the 1-Fluoroadamantane mediates the generation of LiF in the interfaces, which fosters the interfacial stability, contributing to the long-term cycling. Hence, the symmetric cell (Li/Li) exhibits a long-term lithium plating/stripping for over 2,400 h. The 4.3 V LiNi_0.8Mn_0.1Co_0.1O₂/Li all-solid-state battery with the 1-Fluoroadamantane-poly (ethylene oxide) improved electrolyte delivers 600 times, with an impressive capacity retention of 84%. Also, the cell presents high capacity of 210 mA·h/g, and 170 mA·h/g at 0.1 C and 0.3 C respectively, rivalling the liquid electrolytes.

Poly (ethylene oxide) (PEO)-based polymer electrolytes show the prospect in all-solid-state lithium metal batteries; however, they present limitations of low room-temperature ionic conductivity, and interfacial incompatibility with high voltage cathodes. Therefore, a salt engineering of 1, 1, 2, 2, 3, 3-hexafluoropropane-1, 3-disulfonimide lithium salt (LiHFDF)/LiTFSI system was developed in PEO-based electrolyte, demonstrating to effectively regulate Li ion transport and improve the interfacial stability under high voltage. We show, by manipulating the interaction between PEO matrix and TFSI⁻-HFDF⁻, the optimized solid-state polymer electrolyte achieves maximum Li⁺ conduction of 1.24 × 10⁻⁴ S cm⁻¹ at 40 °C, which is almost 3 times of the baseline. Also, the optimized polymer electrolyte demonstrates outstanding stable cycling in the LiFePO₄/Li and LiNi_0.8Mn_0.1Co_0.1O₂/Li (3.0–4.4 V, 200 cycles) based all-solid-state lithium batteries at 40 °C.