Enhanced Crystallinity, Dielectric, and Energy Harvesting Performances of Surface‐Treated Barium Titanate Hollow Nanospheres/PVDF Nanocomposites

Enhancement of the energy harvesting performance and dielectric constants of poly(vinylidene fluoride) (PVDF)‐based capacitors is realized by incorporating 16 wt% of surface‐treated BaTiO3 hollow nanospheres (HNSs) in comparison with the pristine PVDF. The fabricated BaTiO3 HNSs with particle sizes of ≈20 nm and BET surface area of 297 m2 g−1 are treated by three different surface modifiers. The changes in crystallinity of the PVDF containing the surface‐treated BaTiO3 HNSs are induced by both enlarged surface areas and increased surface functionality of the HNSs. Effects of such surface functionalities on the crystalline, dielectric, and energy harvesting performances of the nanocomposites are systematically investigated to identify the optimal surface modifier to enhance the energy density of the nanocomposites. Consequently, these changes in crystallinity lead to higher dielectric constants (ε′ ≈ 109.6) and energy density (Ue ≈ 21.7 J cm−3) with highly retained breakdown strength (E = 3.81 × 103 kV cm−1) compared to pristine PVDF (ε′ ≈ 11.6 and Ue ≈ 2.16 J cm−3 at 3.98 × 103 kV cm−1), indicating their potential as high energy density capacitors.