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Polyimide (PI) and its derivative polyetherimide (PEI) have been widely investigated as promising candidates for dielectric energy storage due to their excellent intrinsic features. However, most of the current research for PI- or PEI-based dielectric nanocomposites only focuses on a certain polar group contained in a dianhydride monomer, while there are very few studies on exploring the effect of a series of polar groups derived from various dianhydride monomers on the dielectric properties of nanocomposites. To fill this gap, we herein fabricated and investigated a series of novel hyperbranched polyimides grafted on barium titanate nanoparticles (HBPI@BT) using different dianhydride monomers and their nanocomposites with the PEI matrix. The results showed that sophisticated hyperbranched structures effectively alleviated the incompatibility between fillers and the matrix, thus significantly improving the bonding energy of nanocomposites, especially for HBPI-S@BT/PEI (797.7 kJ/mol). The U d of HBPI-S@BT/PEI reached 8.38 J/cm3, which is 3.3 times higher than that of pure PEI. The HBPI-F@BT/PEI nanocomposites achieved high breakdown strength (∼500 MV/m) and low dielectric loss (0.008) simultaneously. The dielectric constants of HBPI@BT/PEI nanocomposites remained at a stable level from 25 to 150 °C. This work provides us promising hyperbranched structured materials for potentially advanced dielectric applications such as field effect transistors.

The development of high-performance antiferroelectric ceramics/polymeric materials with great thermal stability has attracted considerable interest due to their extensive use in efficient power sources and electronic devices. Nevertheless, the high energy storage density and thermal stability of dielectrics are seriously restricted due to their poor processibility and weakened breakdown strength (E b ). To resolve these tough issues, it would be highly effective and feasible if an organically modified highaspect-ratio one-dimensional (1D) antiferroelectric ceramic can be employed. Specifically, the 1D nanofiller can extend the breakdown path and improve the local electric field distribution while the organic modification endows dielectrics with enhanced interface polarization and improved compatibility, thus yielding high energy storage density. Herein, a series of high-aspect-ratio 1D NaNbO 3 nanofiller with organic insulating reduced polyaniline (R-PANI) layer are synthesized by the oxidative polymerization and then introduced into the polyetherimide (PEI) matrix. The prepared NaNbO 3 @R-PANI/PEI nanocomposites possess enhanced dielectric constant up to 9.8 as well as ultralow dielectric loss (0.009) while maintaining the high energy density of 2.46 J/cm 3 (1.4 times of that for pure PEI) and high efficiency of 82.6% at 200 MV/m at a small loading of 3 vol %. Depending on the unique structure of the coated R-PANI, the 3 vol % NaNbO 3 @R-PANI/PEI increased the energy density up to 4.4 J/cm 3 and maintained high efficiency of 70.9% at 200 MV/m under 150 °C, therefore making it a potential candidate for polymeric dielectric materials used in extreme environments.

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The development of pulse power systems and electric power transmission systems urgently require the innovation of dielectric materials possessing high-temperature durability, high energy storage density, and efficient charge–discharge performance. This study introduces a core-double-shell-structured iron(II,III) oxide@barium titanate@silicon dioxide/polyetherimide (Fe3O4@BaTiO3@SiO2/PEI) nanocomposite, where the highly conductive Fe3O4 core provides the foundation for the formation of microcapacitor structures within the material. The inclusion of the ferroelectric ceramic BaTiO3 shell enhances the composite’s polarization and interfacial polarization strength while impeding free charge transfer. The outer insulating SiO2 shell contributes excellent interface compatibility and charge isolation effects. With a filler content of 9 wt%, the Fe3O4@BaTiO3@SiO2/PEI nanocomposite achieves a dielectric constant of 10.6, a dielectric loss of 0.017, a high energy density of 5.82 J cm−3, and a charge–discharge efficiency (η) of 72%. The innovative aspect of this research is the design of nanoparticles with a core-double-shell structure and their PEI-based nanocomposites, effectively enhancing the dielectric and energy storage performance. This study provides new insights and experimental evidence for the design and development of high-performance dielectric materials, offering significant implications for the fields of electronic devices and energy storage.