Novel inorganic fillers of 1D hydroxyapatite nanowires induced superior energy storage performances of P(VDF–HFP)-based composite films

Abstract

High-performance flexible dielectric capacitors have a decisive effect in advanced electronics and electrical power systems. Nevertheless, the discharge energy density (U_d) of dielectric capacitors is bounded by their weak breakdown strength (E_b) and low dielectric constant (K). In this work, mediate dielectric constant one-dimensional hydroxyapatite nanowires (HAP NWs) were synthesized and applied in poly(vinylidene fluoride-co-hexafluoropropene)-based (P(VDF–HFP)) nanocomposites for energy storage application. To mitigate electric field distortion and suppress free charge migration in nanocomposites, Al₂O₃ was insulated as an interfacial layer incorporated between 1D HAP NWs and polymer matrices, which were identified via phase field simulations and experimental results. Accordingly, P(VDF–HFP)/HAP@Al₂O₃ NWs composite films exhibit an excellent U_d of ∼27.6 J cm⁻³ accompanied by a high charging/discharging efficiency (η) of ∼72.9% at 650 MV m⁻¹, which is ∼190% over neat P(VDF–HFP) (∼9.5 J cm⁻³ at 500 MV m⁻¹) and ∼2200% improvements of bench-mark biaxially oriented polypropylene (∼1.2 J cm⁻³ at 650 MV m⁻¹). This research offers a paradigmatic design to polymer-based composite films with high U_d and η for application in dielectric capacitors.