Inorganic‐Directed Charge Delocalization Channels: Boosting Uniform Charge Distribution and Rapid Na + Transport for Solid‐State Sodium Metal Batteries

ABSTRACT Composite polymer electrolytes (CPEs) are promising for all‐solid‐state sodium metal batteries but suffer from low ionic conductivity, which stems from limited Na‐salt dissociation and narrow polymer amorphous domains, as well as sluggish ion transport caused by discontinuous composite interfacial charge‐transfer paths, and poor electrode/electrolyte interfacial stability. This study proposes an original molecular interface engineering strategy: inorganic Zr 4+ induces organic phase reconstruction to build continuous high‐speed ion channels, simultaneously accelerating Na‐salt dissociation and reducing ion migration energy barriers. Zr 4+ directs the oriented reorganization of polar groups (─C≡N) to alleviate Na‐metal anode interfacial passivation, facilitate NaF/Na 3 N‐rich stable solid electrolyte interphase formation, and enable uniform Na deposition. Moreover, Zr─N═C metal‐ligand coordination at the organic/inorganic interface induces interfacial electronic coupling and charge redistribution, promoting fast Na + migration along continuous coordination pathways. The developed CPEs, denoted as polyacrylonitrile‐metal organic framework@polyethylene oxide‐NaN(SO 2 CF 3 ) 2 (PM@PN), show a synergistic interface‐bulk effect that significantly enhances electrolyte performance, as evidenced by a reduced apparent activation energy of 0.027 eV (derived from Vogel–Tammann–Fulcher, VTF fitting above T m ), an enhanced ionic conductivity of 3.52 × 10 −4 S cm −1 , and a Na + transference number of 0.67 at 60°C, along with an expanded electrochemical window of 5.06 V. The Na|PM@PN|Na symmetric cell demonstrates 0.56 mA cm −2 critical current density and stable Na deposition/stripping over 700 h at 0.4 mA cm −2 . Additionally, the assembled Na 3 V 2 (PO 4 ) 3 |PM@PN|Na full cell maintains 93.99% capacity retention after 200 cycles at 0.1 C, confirming PM@PN's applicability in advanced all‐solid‐state sodium metal batteries.