No abstract

Dielectric capacitors are promising for high power energy storage, but their breakdown strength (Eb) and energy density (Ue) usually degrade rapidly at high temperatures. Adding boron nitride (BN) nanosheets can improve the Eb and high‐temperature endurance but with a limited Ue due to its low dielectric constant. Here, freestanding single‐crystalline BaZr0.2Ti0.8O3 (BZT) membranes with high dielectric constant are fabricated, and introduced into BN doped polyetherimide (PEI) to obtain laminated PEI–BN/BZT/PEI–BN composites. At room temperature, the composite shows a maximum Ue of 17.94 J cm−3 at 730 MV m−1, which is more than two times the pure PEI. Particularly, the composites exhibit excellent dielectric‐temperature stability between 25 and 150 °C. An outstanding Ue = 7.90 J cm−3 is obtained at a relatively large electric field of 650 MV m−1 under 150 °C, which is superior to the most high‐temperature dielectric capacitors reported so far. Phase‐field simulation reveals that the depolarization electric field generated at the BZT/PEI–BN interfaces can effectively reduce carrier mobility, leading to the remarkable enhancement of the Eb and Ue over a wide temperature range. This work provides a promising and scalable route to develop sandwich‐structured composites with prominent energy storage performances for high‐temperature capacitive applications.

This is a repository copy of Multiple local symmetries result in a common average polar axis in high-strain BiFeO3-based ceramics.

Inorganic/organic dielectric composites are very attractive for high energy density electrostatic capacitors. Usually, linear dielectric and ferroelectric materials are chosen as inorganic fillers to improve energy storage performance. Antiferroelectric (AFE) materials, especially single‐crystalline AFE oxides, have relatively high efficiency and higher density than linear dielectrics or ferroelectrics. However, adding single‐crystalline AFE oxides into polymers to construct composite with improved energy storage performance remains elusive. In this study, high‐quality freestanding single‐crystalline PbZrO3 membranes are obtained by a water‐soluble sacrificial layer method. They exhibit classic AFE behavior and then 2D–2D type PbZrO3/PVDF composites with the different film thicknesses of PbZrO3 (0.1‐0.4 µm) is constructed. Their dielectric properties and polarization response improve significantly as compared to pure PVDF and are optimized in the PbZrO3(0.3 µm)/PVDF composite. Consequently, a record‐high energy density of 43.3 J cm−3 is achieved at a large breakdown strength of 750 MV m−1. Phase‐field simulation indicates that inserting PbZrO3 membranes effectively reduces the breakdown path. Single‐crystalline AFE oxide membranes will be useful fillers for composite‐based high‐power capacitors.

In article number 2300962, Bin Peng, Houbing Huang, Ming Liu, and co-workers introduce a freestanding single-crystalline ferroelectric membrane to fabricate sandwich-structured inorganic/ organic composites, which exhibit good dielectric-temperature stability and superior energy-storage performance. This effective strategy can underlie promoting the energy-storage performance of dielectric capacitors at high temperatures, thereby accelerating their application in advanced industrial fields.