Novel relaxor ferroelectric BTWO nanofillers for improving the energy storage performance of polymer-based dielectric composites

The fast growth of electronic gadgets and power systems has increased the demand for high energy-storage polymer-based film capacitors, However, because of the relatively low dielectric constant (εr), the discharged energy density (Ud) is severely limited, so increasing the εr of nanocomposites is an effective way to increase Ud. In this paper, Bi6Ti5WO22 (BTWO), a novel non-perovskite relaxation ferroelectric ceramic, is selected as nanofillers due to its ultra-low loss and high tunable dielectric constant, and BTWO/P(VDF-HFP) nanocomposites are prepared by compounding with ferroelectric polymers. BTWO nanoparticles' high εr (∼2200) and low loss (∼0.001) increase not only the breakdown strength (Eb) and dielectric properties of nanocomposites, but also their insulating and mechanical characteristics. It is worth noting that when the 5 vol% BTWO nanofillers are loaded, the εr of the nanocomposite is 11.3 and the highest Eb is up to 575 MV·m−1, and the optimal Ud and efficiency (η), with 22.6 J·cm−3 and 71.3 %, are attained at the same moment. In this work, a new relaxation ferroelectric ceramic BTWO is selected as the filler, which provides a new strategic route for the preparation of energy storage polymer-based dielectric.