Nano‐Confined Synergistic Conduction Enables Electrolytes for All‐Solid‐State Lithium Metal Batteries

Abstract An ultrathin (15 µm) composite polymer solid‐state electrolyte is engineered by embedding a dual‐polymer matrix (PEO/PVDF‐HFP) and nano‐LATP particles within a negatively charged nanofiber scaffold (PPLNF). This architecture enables a nano‐confined synergistic conduction (NCSC) mechanism, which electrostatic repulsion from functionalized pore walls excludes TFSI − anions, while LATP promotes LiTFSI dissociation and chemically anchors anions via Lewis acid sites. This dual action localizes anions and elevates free lithium ion (Li⁺) concentration/mobility, while low‐crystallinity polymer segments synergize with the scaffold to form efficient Li⁺ transport channels. The PPLNF achieves high ionic conductivity (1.04 × 10 −3 S cm −1 at 25 °C), Li⁺ transference number (0.75), and electrochemical stability (>5.0 V). It demonstrates exceptional interfacial compatibility, dendrite‐free Li anode cycling over 1000 h, and a critical current density of 2.0 mA cm −2 . NCM811||PPLNF||Li full cells retain >90% capacity after 200 cycles. This work establishes NCSC as a new paradigm for designing high‐performance solid‐state electrolytes toward next‐generation lithium metal batteries.