Yunchuan Xie

The inherent conflict between polarization and breakdown strength limits the development of high-energy-density polymer dielectrics with both high efficiency and reliability. Here, we report an electric-field-directed 3D printing strategy that creates in-situ phase-regulated interfaces. By coupling in-situ electric poling with hydrogen-bond-assisted assembly in a poly(vinylidene fluoride)-based composite, we successfully construct in-situ phase-regulated interfaces that enable a seamless integration of a surface charge-blocking layer, a bulk deep-trap network, and a highly oriented polar crystalline matrix. This multi-scale engineered dielectric overcomes the traditional polarization-insulation trade-off. It delivers an exceptional discharged energy density of 30.5 J cm-3, an efficiency exceeding 84.5%, and a remarkable breakdown strength of 750 MV m-1. The printed capacitor also demonstrates superior thermal stability and outstanding cycling endurance, retaining over 98.7% of its initial efficiency after 10,000 cycles. This work establishes a scalable manufacturing paradigm for designing high-performance polymer dielectrics, opening new avenues for next-generation energy storage and power electronics.

Dielectrics capable of simultaneous high energy density (Ud), high efficiency (η), and reliable operation at elevated temperatures are urgently needed for advanced electronics and power systems, yet remain a formidable challenge. Here, we report a bio-based interfacial engineering strategy that employs wide-bandgap, polar cellulose to conformally coat high-k TiO2 nanosheets, creating a core-shell structured filler. When incorporated into a polyetherimide (PEIs) matrix, the cellulose shell simultaneously enhances filler dispersion and introduces deep charge traps at the interface. This synergistic effect yields a remarkable combination of high dielectric polarization and strongly suppressed conduction loss at high temperatures. The resulting composite with only 2 wt% filler achieves an electrical breakdown strength of 600 MV m-1 and a Ud of 4.05 J cm-3 at 150 °C, retaining a high Ud of 2.89 J cm-3 with 90% η even at 200 °C. Combining thermally stimulated depolarization current analysis and finite-element modelling, we reveal the mechanism by which the cellulose interlayer homogenizes the electric field distribution and immobilizes space charges. This work demonstrates a sustainable materials paradigm using nature-derived polymers for designing high-performance dielectrics operable under extreme conditions, opening a pathway for eco-friendly, high-energy-density capacitive materials.

Ferroelectric polymers are constrained in high-power energy storage capacitors (ESCs) due to their hysteresis losses and low breakdown strength. We tackle this challenge via a dual-pronged strategy encompassing molecular-scale ferroelectric phase regulation and nanoscale heterojunction engineering. The incorporation of trifluoroethylene units into poly(vinylidene fluoride)-chlorotrifluoroethylene disrupts the ferroelectric long-range order, inducing a relaxor state with dynamic polar nanoregions (PNRs) to minimize hysteresis. Simultaneously, ZnO@ZnS nanoparticles refine PNRs and introduce deep charge traps via interfacial band engineering, thereby drastically suppressing electrical conduction. This synergistic strategy employs phase regulation to reduce dipolar loss and heterojunction engineering to curb conduction loss, leading to a greatly increased breakdown strength and reduced dissipation. The resulting nanocomposite achieves a high discharged energy density of 23.8 J cm−3 at 550 MV m−1 with 80% efficiency and robust cycling stability (>5000 cycles) and establishes a transformative pathway for ultrahigh-performance ESCs.

Main-chain programming of PAEK integrates rigid, polar, and crosslinkable units to decouple dielectric polarization from charge transport, achieving reliable high-temperature energy storage with suppressed loss and enhanced breakdown strength.

In this study, the high‐performance all‐organic epoxy composites, aramid nanofibers/phenol‐hydroxy polyphenylene ether resin/epoxy resin (ANFs/SA90/EP), were fabricated, and a systematic investigation was conducted on their dielectric, mechanical, thermal conductivity, and thermal expansion properties. Firstly, SA90 was introduced to modify epoxy resin, leading to a remarkable improvement in the toughness and thermal resistance of epoxy resin. Subsequently, ANFs were incorporated into the modified matrix to further improve the thermal conductivity and thermal expansion properties. The results indicated that the bending strength, modulus and thermal conductivity of the composite material reached 145 MPa, 3.48 GPa and 0.224 W·m ⁻¹ ·K ⁻¹ , respectively, representing an increase of 12%, 10% and 30% compared to the pure epoxy. Meanwhile, the coefficient of thermal expansion (CTE) of the composite material dropped to 77.3 ppm·K ⁻¹ , a reduction of about 25% compared with pure epoxy. These significant improvements in performance are mainly attributed to the strong hydrogen bonding interactions formed between ANFs and the matrix, which significantly enhance the interfacial compatibility, thereby effectively improving the mechanical and thermal expansion properties. Moreover, the incorporation of ANFs established efficient thermal conduction pathways within the composite material, significantly enhancing its thermal conductivity. In addition, the incorporation of ANFs further optimized the dielectric properties of the composite material. At 1 MHz, the dielectric loss was reduced to merely 0.015, representing a decrease of approximately 32% compared to pure epoxy. This study provides innovative ideas and effective strategies for the development of all‐organic epoxy packaging materials.

The development of polymer dielectrics with both high energy density and low energy loss is a formidable challenge in the area of high-temperature dielectric energy storage. To address this challenge, a class of polymers (Parylene F) are designed by alternating fluorinated aromatic rings and vinyl groups in the polymer chain to confine the conjugating sequence and broaden the bandgap with the fluorine effect. The target films with desired thickness, ultra-high purity, and a wide bandgap are facilely fabricated by a one-step chemical vapor deposition (CVD) technique from monomers. The symmetric and bulky aromatic structures exhibit high crystalline performance and excellent stability at high temperature. The presence of strongly electronegative fluorine atoms effectively enhances bandgap and electron trapping capability, which effectively reduces the conduction loss as well as the possibility of breakdown at high temperatures. CVD technology avoids the post-processing film-forming process, ensuring the fabrication of thin films with high quality. These benefits allow Parylene F films to effectively store electrical energy at temperature up to 150 °C, exhibiting a record discharged energy density of 2.92 J cm⁻³ at charge–discharge efficiency exceeding 90%. This work provides a new idea for the design and synthesis of all-organic polymer dielectric films for high temperature applications.

This work presents a facile strategy to significantly boost the capacitive performance of aromatic polymer with simple preparation process. At 150 °C, the composite films exhibit remarkable comparative performance, U_e = 10.1 J cm⁻³ and η > 90%.