Improved energy density in core-shell poly(dopamine) coated barium titanate/poly(fluorovinylidene-co-trifluoroethylene) nanocomposite with interfacial polarization

Polymer dielectric nanocomposite with high dielectric property and large power density is one of the most promising candidates in wearable electronics and polymer film capacitors due to its lightweight and flexibility as well as processability. In order to improve energy density and charge-discharge efficiency of film capacitor, in which the interfacial compatibility between the fillers and matrix often plays a key role in the enhancement of the electrical energy capability. In this work, the core-shell architecture with poly(dopamine) (PDA) encapsulated on the barium titanate particles (D-BT) via condensation reaction was tailored to improve the compatibility in polymer nanocomposite. The high dielectric constant of 46.4 with the low loss as 0.07 at 100 Hz is obtained in 15 wt% D-BT/P (VDF-TrFE) nanocomposite due to the interfacial compatibility resulting from the strong hydrogen bonds between PDA segments and macromolecular chains. The recovered energy density of 5 wt% nanocomposite film reaches 3.2 J/cm(3) with the charge-discharge efficiency of 68%, which is attributed to the large content of electroactive phase and interfacial polarization. This work provides a simple technique to improve electrical energy capability, and sheds a light on the enhancement of interfacial mechanism in the polymer nanocomposite for film capacitor.