PVDF‐Nanofibers/PET‐Nonwoven Sandwich Coated with Fine γ‐AlO(OH): A Bilayer Hybrid Composite Separator for Lithium‐Ion Batteries

Nanofiber‐based separators fabricated via electrospinning for lithium‐ion batteries have garnered widespread attention due to their attractive porous characteristics, improved thermal stability, and high electrolyte wettability. A double‐layer PVDF/PET/γ‐AlO(OH) hybrid composite membrane is prepared by combining simple electrospinning techniques with drop casting onto thermally pressed PET/PVDF surfaces, resulting in a finely dispersed and uniform boehmite (γ‐AlO(OH)) coating. The 3D interconnected structure of the PVDF/PET/γ‐AlO(OH) hybrid composite membrane exhibits excellent mechanical properties and demonstrates outstanding electrolyte absorption, with supervisor electrolyte uptake of 582.5% and remarkable ionic conductivity of 1.2 × 10 −2 S cm −1 . Even after heating at 130 °C for 1 h, the membrane maintains good thermal stability. Li 4 Ti 5 O 12 /LiNiMnCoO 2 batteries employing the double‐layer PVDF/PET/γ‐AlO(OH) hybrid composite membrane exhibit exceptional discharge capacity (105.7 mAh g −1 at 0.2 C) and outstanding capacity retention (100%). The battery performance results clearly demonstrate the suitability of the double‐layer PVDF/PET/γ‐AlO(OH) hybrid composite membrane as a safe separator for lithium‐ion batteries.