β‐<scp>CD</scp> and Succinonitrile Reinforced Polymer Electrolytes for All‐Solid‐State Lithium Metal Batteries

ABSTRACT With the advancement of the global dual‐carbon goal, green technology has become a priority in the energy field. Among energy storage technologies, all‐solid‐state batteries attract significant attention due to their high energy density, enhanced safety, and long cycle life. Poly(ethylene oxide) (PEO)‐based polymer solid‐state electrolytes are a research hotspot for next‐generation lithium‐metal batteries because of their flexibility, film‐forming capabilities, and compatibility with lithium salts. In this study, cyclodextrin (β‐CD) is employed as a green filler and combined with high‐modulus polyacrylonitrile (PAN) fibers and plastic crystalline succinonitrile (SN) to synergistically enhance the electrochemical and mechanical properties of PEO‐based electrolytes. The PAN/PEO/LiClO 4 /β‐CD/SN electrolyte achieves an ionic conductivity of 6.5 × 10 −5 S cm −1 at 30°C and a lithium ion transference number of 0.33 at 80°C. PAN fiber significantly improves mechanical properties, achieving a tensile strength exceeding eight times that of the PEO/LiClO 4 membrane. In Li/Li symmetric batteries, the electrolyte demonstrates excellent interfacial stability for over 1100 h at 0.1 mA cm −2 . Additionally, the LiFePO 4 |PAN/PEO/LiClO 4 /β‐CD/SN|Li coin cell exhibits an initial discharge specific capacity of 148 mAh g −1 at 80°C and 0.5C, retaining 70% capacity after 200 cycles. This study presents a novel design approach for utilizing green fillers in SPEs.