Tailored interface with varied electrical performance in core–shell BaTiO3@C/poly(vinylidene fluoride-chlorotrifluoroethylene) dielectric composite film

Polymer film capacitor with large power density is potentially embedded in energy suppliers and wearable devices. Currently, the strategy of polymer composite is an effective solution for the enhancement of energy density for dielectric film. Exploring the relation between neighboring interface and polarized response of composite is the primary route for the improvement of energy storage capability in polymer film. In this work, the interface with tailored electrical conductivity has been constructed in carbon-coated BaTiO 3 /poly(vinylidene fluoride-chlorotrifluoroethylene) (BT@C/P(VDF-CTFE)) composite. Core–shell BT@C particles with various calcined crystal structures were synthesized via sol–gel method with following carbonization. The calcination process affects the constitution of graphitic carbon that determines the electrical resistivity of received BT@C particles. The presence of carbon layer on the cubic BT core was evidenced by X-ray photoelectron spectroscopy and transmission electron microscope. BT@C/P(VDF-CTFE) composite with tailored conductive interface was prepared through the solution casting method. The electric displacement of composite is improved due to the interfacial polarization. The electrical resistivity depends on the permeation effect of interfacial carriers, resulting in the decrease of energy efficiency during charge–discharge cycle. The exploration between interface effect and polarization provides insightful prospects on interfacial design of polymer composite for film capacitor.