Large Segment Bandgap, Steric Hindrance Structure and Organic Semiconductor Filler Collaborative Designs for Superior High‐Temperature Energy Storage of Aromatic Polymers

ABSTRACT Polymer capacitors with superior discharged energy storage density ( U _d ) and charging‐discharging efficiency ( η ) are necessary for modern electronic and electric devices. Molecular engineering is a crucial trend for designing polymers, but the individual and synergetic effects of segment bandgap ( E _g ) and steric hindrance, both governed by molecular structure on charge transport and U _d are unclear. Herein, a molecular strategy that combines the advantages of large segment E _g , steric hindrance, and organic semiconductor fillers is proposed for aromatic polymer. Through screening 53 aromatic polymers via DFT simulation and optimizing mass contents of PCBM, the 0.3%PCBM fillers are doped into the designed aromatic polymer with large E _g and steric hindrance structure, which achieves an ultra‐high U _d of 7.93 J/cm ³ under 775 MV/m at 150°C when η >85%, which is superior to most investigations previously. The large segment E _g , steric hindrance and PCBM particles, respectively, inhibit intermolecular and intramolecular charge transfer, alongmolecular charge transfer, and charge migration and injection, attributing to the depression of charge transport multi‐processes and superior U _d . The effective molecular engineering indicates that the depression of charge transport multi‐processes greatly enhances U _d , offering a strategy to enhance U _d for high‐temperature capacitor films in advanced applications.