Core‐shell structured BaTiO₃@SiO₂@PDA for high dielectric property nanocomposites with ultrahigh energy density

Abstract

Flexible nanocomposite dielectrics with high dielectric constant and discharge energy density have broad application prospects in the field of energy storage. However, dielectrics with high dielectric constant tend to have a high dielectric loss. Herein, we prepared a dielectric composite material with ultra‐high discharge energy density by modifying the interface between nanoparticles and poly(vinylidene fluoride‐co‐hexafluoropropylene) (P[VDF‐HFP]). After coating a shell of insulating amorphous SiO2 (~7 nm) outside the barium titanate (BT), the electric field concentration and current density inside BT particles can be significantly reduced. In addition, coating the SiO2 shell with a polydopamine (PDA) shell (~7 nm) not only enhances the interface interaction between the nanoparticles and the polymer matrix, but also can form lots of microcapacitors in the composite. As a result, an ultra‐high discharge energy density of 13.78 J/cm3 at the expense of relatively inconspicuous efficiency (~59.8%) in the BT@SiO2@PDA/P (VDF‐HFP) with 2.5 wt% loading has been achieved under 460 kV/mm. This is mainly attributed to the increases of dielectric constant from 12.1 to 14.2 and the relatively low dielectric loss (0.086) at 100 Hz. Moreover, compared with the pure P (VDF‐HFP) (400 kV/mm), the breakdown voltage of the composite with 2.5 wt% loading is surged to 460 kV/mm, which benefited from the hindrance of nanoparticles on carrier migration at low content. This work has realized a thin‐film dielectric with ultra‐high discharge energy density through a novel design of the nanoparticle structure, providing a theoretical direction for the development of polymer dielectric capacitors.

Study on structural and functional properties of porous SiO2 core‐shell construction/polyethylene nanocomposites with enhanced interfacial interaction

“…The Weibull distribution is often used to statistically analyze the breakdown strength of a material. The two‐parameter Weibull expression is as follow: 45 where, P( E ) presents cumulative failure probability, E is the measured electric strength during breakdown. E 0 is the experimental electric field strength when the cumulative failure probability is 63.2%.…”

Enhancing energy storage property of polymer nanocomposites by rationally regulating shell thickness of core–shell structured nanoparticles

“…Figure 4A presents that strong diffraction peaks F I G U R E 2 Transmission electron microscopy images of (A) BT@25SO, (B) BT@15SO and (C) BT@5SO nanoparticles, and (D) HRTEM images of BT@5SO nanoparticles and its magnified illustration 211), (220), and (310) crystal planes, respectively. [30,31] However, the XRD characteristic peaks of SiO 2 are not visible due to the amorphous state of SiO 2 shell. In addition, Figure 4B shows that PVDF-based composites process a two-phase composite system of crystal BaTiO 3 and semi-crystal PVDF with a α crystal at 2θ ≈ 17.69 , 18.37 , 19.97 , and 26.48 corresponded to the (100), (020), (110), and (021) crystal plane, respectively.…”

Design and characterization of molecular, crystal and interfacial structures of PVDF-based dielectric nanocomposites for electric energy storage

“…The discharge energy density of the BT@PDA@Ag/P(VDF–HFP) composite reaches 3.21 J cm −3 , which is higher than 2.72 J cm −3 of BT@PDA/P(VDF–HFP) and 2.45 J cm −3 of BT/P(VDF–HFP) under the same electric field. Wang et al 154 reported that a new type of core@inorganic-organic double shell of BT@SiO 2 @PDA nanoparticles was synthesized. First, the inorganic SO 2 shell was prepared by a simple hydrothermal synthesis method to raise the breakdown strength of the composite.…”