High energy density in poly(vinylidene fluoride-trifluoroethylene) composite incorporated with modified halloysite nanotubular architecture

Abstract Dielectric polymer capacitors with high power density as well as efficient charge-discharge rate are widely investigated in past decades. The development of polymer film with large electric capability has become the research topic for the energy storage of advanced power equipment. Here the tubular architecture in poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) composite film has been constructed with modified halloysite nanotubes (HNTs) to accomplish an effective diffusion of matter and energy units under high electric field. The nanotube surface was functionalized with poly(dopamine) (PDA) in tris-buffer solution to improve the compatibility with fluoropolymer. The energy capability of P(VDF-TrFE) composite film is enhanced owing to the large content of electroactive phase and interfacial polarization. The dielectric constant in 4 wt% PDA-HNTs/P(VDF-TrFE) film is 34.1 at 100 Hz, and the energy density in 2 wt% composite achieves 5.6 J/cm3 with charge-discharge efficiency of 74% at 250 MV/m based on the efficient transportation of ions within hollow nanotubular structure. This work delivers a simple method to construct the efficient diffusion route in polymer dielectrics for film capacitor with high energy density and cycle efficiency.