Single‐Crystalline BaZr0.2Ti0.8O3 Membranes Enabled High Energy Density in PEI‐Based Composites for High‐Temperature Electrostatic Capacitors

作者：Haixia Liu, Wenxuan Zhu, Qi Mao, Bin Peng, Yiwei Xu, Guohua Dong, Bohan Chen, Ruobo Peng, Yanan Zhao, Ziyao Zhou, Sen Yang, Houbing Huang, Ming Liu · 发表于：Advanced Materials · 年份：2023 · DOI：10.1002/adma.202300962 · 被引用次数：59 · 研究领域：Dielectric materials and actuators、Ferroelectric and Piezoelectric Materials、Advanced Sensor and Energy Harvesting Materials

Abstract Dielectric capacitors are promising for high power energy storage, but their breakdown strength ( E b ) and energy density ( U e ) usually degrade rapidly at high temperatures. Adding boron nitride (BN) nanosheets can improve the E b and high‐temperature endurance but with a limited U e due to its low dielectric constant. Here, freestanding single‐crystalline BaZr 0.2 Ti 0.8 O 3 (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 U e 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 U e = 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 E b and U e 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.