In Situ Coordinated MOF-Polymer Composite Electrolyte for Solid-State Lithium Metal Batteries with Exceptional High-Rate Performance.

The integration of metal organic frameworks (MOFs) and electrospun polymer fibers offers the potential to achieve uniform dispersion and high loading of fillers, providing a unique perspective for advancing composite solid electrolytes in solid-state lithium metal batteries. In this work, a composite solid electrolyte is fabricated through a combination of electrospinning and chemical immersion, facilitating the in situ nucleation and growth of HKUST-1 on polyacrylonitrile (PAN) electrospun nanofibers. The in situ coordinated HKUST-1 particles not only modify the solvation structure of Li+ and the coordination environment of TFSI-, but also encapsulate PAN fibers to mitigate interfacial side reactions with lithium metal, thereby improving interfacial stability. Consequently, the solid-state electrolyte achieves a high Li ion transference number of 0.77 and an impressive critical current density of 4.5 mA cm-2. The assembled Li||Li symmetric cell exhibits stable operation for over 4000 h at 4.0 mA cm-2, while Li||LFP and Li||NCM811 cells demonstrate exceptional rate capability and cycling stability. This work provides valuable insights into the design and fabrication of MOF/polymer-based composite solid electrolytes.