材料科学
聚合物
电介质
共轭体系
偶极子
热稳定性
化学物理
超分子聚合物
氢键
化学工程
光电子学
纳米技术
复合材料
分子
有机化学
化学
物理
工程类
作者
J C Li,Yan Gao,Yupeng Jin,Tian Zhang
标识
DOI:10.1002/adma.202411806
摘要
Abstract Polymer dielectrics possess outstanding advantages for high‐power energy storage applications such as high breakdown strength ( E b ) and efficiency ( η ), while both of them decrease rapidly at elevated temperatures. Although several strategies have been evaluated to enhance Eb and heat resistance, the discharged energy density ( U d ) is still limited by the planar conjugated structure. In this study, a novel approach to manipulate polymer morphology is introduced, thereby influencing dielectric properties. A range of polyurea (PU)‐based polymers are predicted from different structural unit combinations by machine learning and synthesized two representative polymers with high dielectric constants ( K ) and thermal stability. These polymers are combined with PI to form a twisted polymer via hydrogen bonding interactions (HNP). Both experimental results and computational simulations demonstrate the twisted structure disrupts the conjugated structure to widen the bandgap and increase dipole moment through the twisting of polar groups, leading to simultaneous improvements in both K and E b . Consequently, HNP‐20% achieves an ultrahigh Ud of 6.42 J cm −3 with an efficiency exceeding 90% at 200 °C. This work opens a new avenue to scalable high Ud all‐polymer dielectric for high‐temperature applications.
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