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 (ε_r), the discharged energy density (U_d) is severely limited, so increasing the ε_r of nanocomposites is an effective way to increase U_d. 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 ε_r (∼2200) and low loss (∼0.001) increase not only the breakdown strength (E_b) 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 ε_r of the nanocomposite is 11.3 and the highest E_b is up to 575 MV·m⁻¹, and the optimal U_d 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.