Morphology‐Engineered BaZr 0.2 Ti 0.8 O 3 Nanofibers via Electrospinning for High‐Energy‐Storage PVDF Nanocomposite Film Through β ‐Phase Induction

ABSTRACT One‐dimensional relaxor ferroelectric nanofiller can enhance the dielectric properties of polyvinylidene fluoride (PVDF)‐based composite films. However, the impact of fiber morphology on these properties is unclear, with existing studies lacking systematic investigation. In this work, BaZr 0.2 Ti 0.8 O 3 nanofibers (BZT_nfs) were prepared by electrospinning. A sequential experimental design was used. First, electrospinning parameters were screened at a fixed filler loading of 2.5 vol% to isolate the influence of nanofiber morphology. V 10 C 20 D 20 FR 0.8 , with a mean diameter of 81.6 nm, mean length of 7.6 μm, and aspect ratio of 93:1, can significantly promote β‐phase formation in PVDF (with a β‐phase content up to 91.2%) and improve the permittivity of the composites. Therefore, it was selected for the subsequent filler‐loading investigation. Toward PVDF matrix doped with BZT_nfs at a volume ratio of 1.25 vol%, the composite film shows a dielectric constant of 12.9 at 10 3 Hz, a breakdown strength of 450 kV/mm, a maximum discharge energy density of 12.2 J/cm 3 , and a charge–discharge efficiency of 61.3%. Optimizing electrospinning parameters enables precise regulation of BZT_nfs morphology and establishes the structure–property relationship of “fiber morphology—crystal phase transition ‐ dielectric properties”, providing a feasible strategy for preparing one‐dimensional relaxor ferroelectric nanofiller in high‐energy storage dielectric composites.