Synergistic Molecular Engineering of Crosslinked Polymer Dielectrics for High‐Temperature Capacitive Energy Storage

作者：Yan He, Quan Sun, Rui Xue, Qi Wang, Aijiao Guan, Pingxia Zhang, Jingcheng Xu, Zhaoyu Ran, Qi Li, Wenxin Fu · 发表于：Advanced Materials · 年份：2025 · DOI：10.1002/adma.202513483 · 被引用次数：11 · 研究领域：Dielectric materials and actuators、Ferroelectric and Piezoelectric Materials、Advanced Sensor and Energy Harvesting Materials

Abstract Polymer dielectric capacitors are critical for high‐temperature energy storage, yet current materials face a trade‐off between thermal stability and capacitive performance due to conduction loss or insufficient polarization. Here, a modular molecular engineering to simultaneously optimize molecular polarity, topological crosslinking, and free volume in alicyclic polymers is designed. By incorporating thermally crosslinkable benzocyclobutene (BCB) and sulfone‐methyl (─SO 2 CH 3 ) groups into norbornene‐based monomers via ring‐opening metathesis polymerization (ROMP), crosslinked networks with decoupled non‐conjugated backbones and polar moieties are constructed. The polymers exhibit a wide optical bandgap ( E g > 3.7 eV), high thermal stability ( T g > 350 °C), and suppressed dissipation ( D f ≈ 0.0006). Optimized P50‐B250 delivers an exceptional discharged energy density ( U d ) of 8.00 J cm −3 at 150 °C (≥90% efficiency), while fully crosslinked P0‐B300 retained U d of 7.34 J cm −3 at 200 °C and 4.65 J cm −3 at 250 °C, outperforming conventional dielectrics. Molecular dynamics (MD) simulations revealed that crosslinking increases free volume fraction by ≈40%, inhibiting interchain charge transfer complexes (CTCs). Density functional theory (DFT) calculations confirm that sulfonyl‐enhanced polarization and crosslinking collectively restrict charge migration. This work establishes a general framework for designing polymer dielectrics by integrating structural mo...