Significant Enhancement of Energy Storage Performances by Regulating the Dielectric Contrast between Adjacent Layers in the Heterostructural Composites

Abstract

Polymer-based composites with high discharged energy density and energy efficiency are tremendously desired for modern electronic systems. In this study, a bilayer heterostructural composite (named as THV/xBT) with excellent energy storage performances was constructed by one layer of a BaTiO 3 nanoparticles (BT nps)-filled P(VDF-HFP) composite and another layer of a pure poly(tetrafluoroethylene-vinylidene fluoride-hexafluoropropylene) (THV) polymer with a moderate dielectric constant and high breakdown strength. The experimental and finite element simulation results indicate that the space charges could accumulate at the interfaces between THV/P(VDF-HFP) and BT nps/P(VDF-HFP) by regulating the dielectric contrast between these two adjacent layers. It improves not only the interfacial polarization but also the breakdown strength and limits the leakage current density of THV/xBT composites. As a result, the THV/5BT composite delivers the best energy storage performance with the discharged energy density of 22.7 J/cm 3 , and an energy efficiency of 79.0% is achieved. This work might open up a way for structural design of polymer-based composites with remarkable energy storage performances.

Chemical composition tuning induced variable and enhanced dielectric properties of polycrystalline Ga2‐2xWxO3 ceramics

“…The lattice distortion induced slow motion in the polarons is known as polaron hopping. 55,68,69 As it can be seen in Figure 10, the W-doped Ga 2 O 3 ceramics exhibit a linear growth before being achieiving the saturation state at higher frequency. Intrinsic Ga 2 O 3 has the lowest magnitude as compared to other doped GWO samples which forms a cluster as the dopant level increases.…”

“…The polaron is often described in context of a deformable polar medium as a self‐stablilized electronic charge. The lattice distortion induced slow motion in the polarons is known as polaron hopping 55,68,69 . As it can be seen in Figure 10, the W‐doped Ga 2 O 3 ceramics exhibit a linear growth before being achieiving the saturation state at higher frequency.…”

“…Intrinsic Ga 2 O 3 has the lowest magnitude as compared to other doped GWO samples which forms a cluster as the dopant level increases. The underlying mechanism behind this can be explained the following equation 68,69 : where, ω is angular frequency and τ represents the average relaxation time. It is worth noting that for conduction occuring in a localized neighborhood with a small polaron hopping, ω 2 τ 2 < 1, the log ( σ ac − σ dc ) vs log ω 2 will always represent a linear behavior which is clearly evident in Figure 10.…”

“…Intrinsic Ga 2 O 3 has the lowest magnitude as compared to other doped GWO samples which forms a cluster as the dopant level increases. The underlying mechanism behind this can be explained the following equation 68,69 :…”

MgAl LDH nanosheets loaded with Ni nanoparticles: a multifunctional filler for improving the energy storage performance of PVDF-based nanocomposites

“…In order to observe more directly, the logarithm of the absolute value of simulation results is adopted. 49 As shown in Fig. 10, under the applied electric eld, the charges are mainly distributed at the interface of the nanocomposites.…”