Data‐Driven Discovery of MOF–Polymer Synergies Enabling High‐Performance Solid‐State Sodium Batteries

ABSTRACT Solid‐state batteries (SSBs) are widely regarded as a promising next‐generation energy storage technology owing to their intrinsic safety and high energy density. Solid polymer electrolytes (SPEs) have been esteemed as a cost‐effective route to realize commercial SSBs, however, it's hindered by the low ionic conductivity at room temperature. Here, we present a data‐driven strategy to screen a broad library of M‐MOF‐74 structures and identify Zn‐MOF‐74 as an optimal filler for poly(vinylidene difluoride)‐based electrolytes after comprehensive structure‐conductivity correlation analysis and performance prediction. The SPE‐Zn‐MOF electrolyte achieves an ionic conductivity of 1.02 × 10 −3 S cm −1 at room temperature and a high Na + transference number (t Na+ ) of 0.84. Various structural characterizations reveal that Zn‐MOF‐74 suppresses the formation of PVDF microcrystallinity and anomalously inhibits the re‐crystallinity of polymer during cycling, which also promotes anion dissociation through Lewis‐acidic metal sites and the formation of NaF‐rich interphase. These synergies extend the electrochemical stability window up to 5.1 V and support prolonged cycling stability beyond 4000 h in Na||Na cells. When integrated with layered oxide or Na 3 V 2 (PO 4 ) 3 cathodes, the optimized SPE enables both full cells achieving superior cycling stability and excellent rate capability at room temperature.