Manipulating Fluorinated Nanochannels in Porous Aromatic Frameworks for Ultra‐Stable Sodium‐Ion Transport

ABSTRACT Quasi‐solid‐state sodium metal batteries suffer from sluggish Na + transport and unstable interphases due to strong ion pairing and unfavorable solvation structures. Herein, fluorinated nanochannels are constructed by grafting flexible perfluoroalkyl chains into porous aromatic frameworks (PAF‐1‐F), generating a weakly coordinating environment that promotes ion‐pair dissociation and fluorine‐polarization‐assisted Na + transport. The resulting PAF‐1‐F quasi‐solid‐state electrolyte exhibits an impressive ionic conductivity of 2.79 × 10 −4 S cm −1 , a high Na + transference number of 0.562, and a wide electrochemical stability window of 4.98 V. The fluorine‐rich nanochannels further induce the formation of uniform NaF‐rich interphases, enabling stable Na plating/stripping for over 5700 h with suppressed dendritic growth. When evaluated in full cells, the PAF‐1‐F quasi‐solid‐state electrolyte achieves stable cycling over 1300 cycles with 91.3% capacity retention and maintains durable operation for more than 4000 cycles even at −20°C. This work establishes nanochannel‐mediated weak coordination as a strategy for coupling ion transport and interfacial stability in quasi‐solid‐state electrolytes.