Ultrahigh breakdown strength and energy density of polymer nanocomposite containing surface insulated BCZT@BN nanofibers

Novel surface insulated 0.5(Ba 0.7 Ca 0.3 )TiO 3 -0.5Ba(Zr 0.2 Ti 0.8 )O 3 (BCZT) nanofibers adhered with boron nitride nanosheets (BNNSs), named as BCZT@BN, is used as fillers in polyvinylidene fluoride (PVDF)-based nanocomposites . Double layered film which comprises high breakdown strength ( E b ) layer of PVDF/0.8 wt% BNNSs (PBN 0.8 ) and high dielectric constant ( ε r ) layer of PVDF/0.4 wt% BNNSs/ z wt% BCZT@BN (PBN 0.4 BCZT@BN z ) is employed. The E b is largely increased from 380 MV m −1 of pristine PVDF film to 730 MV m −1 of PVDF nanocomposite fed with 0.8 wt% BNNSs, and a high discharge energy density ( U dis ) of 17.9 J cm −3 is achieved at the same time. Furthermore, after introducing 1.6 wt% BCZT@BN in PBN 0.8 -PBN 0.4 BCZT@BN 1.6 nanocomposites, the ε r reaches up to 10.7, which is substantially improved by 119% over that of PBN 0.8 nanocomposite (9.1). Thus, the incorporation of BCZT@BN NFs endows the PBN 0.8 -PBN 0.4 BCZT@BN 1.6 nanocomposite with an impressive energy storage density ( U e ) of 24.3 J cm −3 , which is 3.57 times of pristine PVDF. Finite element simulation analysis reveals that BNNSs adhered on the surface of BCZT NFs exhibit a prominent effect in local electric field elimination and leakage current density dispersion. The strategy provides an innovative approach to enhance the energy storage performance of polymer-based nanocomposites.