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

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.