Yao Zhou

Polymer film capacitors are widely used in electronic devices and power systems, yet their energy storage performance (ESP) deteriorates significantly under harsh operating conditions. Here, we propose a synergistic strategy that integrates bulk physical crosslinking with interfacial plasma regulation to suppress conduction loss and enhance high‐temperature dielectric performance. 4‐cyanobenzaldehyde (4‐CZ) is incorporated into a polyetherimide (PEI) matrix to construct a noncovalent, electrostatically crosslinked network, which simultaneously constrains polymer chain dynamics and introduces charge‐transport barriers, thereby effectively inhibiting carrier migration. In parallel, plasma surface treatment further enhances interfacial trap density and suppresses charge injection. Owing to this synergistic regulation of bulk and interface, the optimized film delivers a discharge energy density ( U _d ) of ∼7.6 J·cm ⁻³ with an efficiency ( η ) of 91.8% at 150°C and 670 MV·m ⁻¹ , markedly outperforming pristine PEI. This work establishes a generalizable design strategy for high‐performance all‐organic polymer dielectrics toward high‐temperature energy storage applications.

Polymer dielectrics are vital for high-power electronics, yet their high-temperature application is fundamentally constrained by the inherent trade-offs among thermal stability, polarization retention, and conduction loss. Here, we mitigate these limitations by integrating high-entropy nanofillers with a preferentially oriented, wide-bandgap inorganic nanocoating to construct a multiscale heterointerfacial architecture. Within this design, entropy-driven compositional disorder enhances the structural stability and polarization response of the nanofillers, while the conformal inorganic network synergistically suppresses carrier injection and modulates bulk trap-mediated transport. Consequently, the engineered composites deliver a discharged energy density of 10.44 J cm⁻³ with 95% efficiency and a breakdown strength of 650 MV m⁻¹ at room temperature. Notably, at 150 °C, the composites retain 8.35 J cm⁻³, 80% efficiency, and a breakdown strength of 610 MV m⁻¹. First-principles calculations and phase-field simulations suggest multiscale field confinement that weakens electrothermal coupling and enhances high-temperature stability. This work establishes a comprehensive, multiscale design paradigm for next-generation polymer dielectric capacitors operating in extreme thermal environments.

In situ growth of ultrasmall nanodots via a nanoconfinement strategy enables polymer nanocomposites to achieve superior high-temperature capacitive performance, yielding a discharged energy density of 7.03 J cm ⁻³ at 200 °C with efficiency above 90%.

A scalable dip-coating method enables the deposition of a broadband SiO ₂ /P (VDF-HFP) composite layer on PET to improve the charge barrier and dielectric strength of polymer capacitors at high temperatures.

The enhancement of the energy storage property of capacitor films at elevated temperature has been considered a critical area of research owing to the essential requirements of capacitor applications. In the present study, a ternary composite system with an improved energy storage property is reported. The ternary composite was composed of PP-graft-AA chains (acrylic acid grafting) and a PP/nano-ZrO₂ matrix and was biaxially oriented into a defect-free film with a thickness of 10 μm. The obtained film (BO(PP/AA/Zr)) exhibited an energy storage density of 7.9 J cm⁻³ at room temperature and maintained a considerably high value of 3.9 J cm⁻³ at 120 °C. The characterization of charge carrier transportation indicated that the effective biaxial orientation and the introduction of the polar grafted functional group and nanofillers increased the activation energy of molecular chain segment motion and deepened electron trap energy levels, which limited the transportation of charge carriers and significantly enhanced the breakdown strength and energy storage property. Moreover, the designed graft-modified chains (acrylic acid grafted) modified the compatibility between the polymer and inorganic nanofiller, thereby improving the processibility of the defect-free thin film. The results of dynamic mechanical analysis and 2D micro-infrared spectra indicated that the graft-modified chains offset the increased elastic rigidity caused by nanoparticles and facilitated the interaction between inorganic nano-ZrO₂ and polymer chains. The study provides a potential solution to the challenge that nanocomposites face during the commercial production of defect-free biaxially oriented films.