Dual‐Functional PDA/CMC‐Li Supramolecular Bridging Networks Unlock Trans‐Phase Li ⁺ Conduction in Composite Solid Electrolytes for High‐Performance Lithium Metal Batteries

ABSTRACT

Composite solid electrolytes (CSEs) hold immense promise for high‐energy‐density solid‐state lithium metal batteries, yet their practical application remains severely hampered by filler agglomeration and sluggish interfacial Li ⁺ transport. Herein, dual‐functional supramolecular bridging networks are constructed by employing lithiated carboxymethyl cellulose (CMC‐Li) as dynamic bridges to interconnect polydopamine (PDA)‐modified Li _6.28 Al _0.24 La ₃ Zr ₂ O ₁₂ (LLZAO) fillers within a PVDF‐HFP matrix. This synergistic architecture helps promote a more uniform filler dispersion and actively mediates ion solvation dynamics via simultaneous anion trapping and cation extraction. Crucially, this dual‐regulation fundamentally mitigates the space‐charge layer (SCL) effect at organic‐inorganic boundaries, actively unlocking a highly efficient trans‐phase Li ⁺ percolation pathway through the LLZAO ceramic bulk, thereby bypassing conventionally sluggish interfacial routes. The resulting spatially homogeneous ion flux may reduce localized current hotspots and suppress lithium dendrite proliferation. Consequently, the optimized PVPL electrolyte empowers Li||Li symmetrical cells to maintain stable plating/stripping over 1400 h. Furthermore, LiFePO ₄ ||PVPL||Li full cells deliver 83% capacity retention after 400 cycles at 2 C, while NCM811||PVPL||Li cells maintain 88% capacity retention over 200 cycles. This dual‐functional bridging strategy establishes a generalizable and effective paradigm for engineering advanced CSEs with optimized structural and Li ⁺ transport kinetics.