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[Display omitted] Polymer-based dielectrics with high thermal conductivity and superb dielectric properties hold great promising for advanced electronic packaging and thermal management application. However, integrating these properties into a single material remains challenging due to their mutually exclusive physical connotations. Here, an ideal dielectric thermally conductive epoxy composite is successfully prepared by incorporating multiscale hybrid fillers of boron nitride microsphere (BNMS) and silicon dioxide coated silicon carbide nanoparticles (SiC@SiO 2). In the resultant composites, the microscale BNMS serve as the principal building blocks to establish the thermally conductive network, while the nanoscale SiC@SiO 2 as bridges to optimize the heat transfer and suppress the interfacial phonon scattering. In addition, the special core–shell nanoarchitecture of SiC@SiO 2 can significantly impede the leakage current and generate a great deal of minicapacitors in the composites. Consequently, favorable thermal conductivity (0.76 W/mK) and dielectric constant (∼8.19) are simultaneously achieved in the BNMS/SiC@SiO 2 /Epoxy composites without compromising the dielectric loss (∼0.022). The strategy described in this study provides important insights into the design of high-performance dielectric composites by capitalizing on the merits of different particles. [ABSTRACT FROM AUTHOR]

Dielectric materials with excellent thermal stability, mechanical properties, and thermal conductivity are highly desirable for advanced electronics and electrical equipment. However, it remains a significant challenge to develop a single material with these properties. Here we describe a new strategy to prepare dielectric paper by combining one-dimensional aramid nanofiber (ANF) with two-dimensional fluorinated graphene (F-graphene) through a vacuum-assisted filtration method. The obtained ANF/F-graphene paper exhibits a low dielectric constant of 1.92 at 103 Hz and its electrical breakdown strength is 17.6% higher than that of the neat ANF paper, owing to the presence of F-graphene, which significantly suppresses the accumulation of space charge in the prepared paper. Moreover, high mechanical strength (>200 MPa), thermal conductivity (6.29 Wm−1K−1), and thermal decomposition temperature (>500°C) are simultaneously achieved for the ANF/F-graphene paper. These findings highlight the fabrication of multifunctional dielectric materials and broaden their practical applications in the field of high-temperature electronics and devices. [ABSTRACT FROM AUTHOR]

The developments in the high-power densities and high integration of electronic devices have put forward higher requirements for advanced thermal management materials (TMMs) to meet the rising demand for heat dissipation. However, it has remained a major challenge to achieve significant enhancement of thermal conductivity (TC) of TMMs without compromising their mechanical and dielectric properties. Here, we report a flexible, thermally conductive composite film that contain aramid nanofiber (ANF) and silver nanoparticles (AgNPs) decorated with boron nitride (BN), the in-plane TC of which is up to 12 W/mK at 40 wt.% filler contents. Such a high TC is attributed to the bridging role of AgNPs, which greatly reduces the interfacial thermal resistance of composites. At the same time, the as-prepared composite films possess outstanding mechanical strength (>126 MPa), owing to the coupling between the ANF network and the favourable hydrogen bonding interaction between the ANF and the functional BN. Moreover, a low dielectric loss (<0.05), high electrical resistivity (~1014 Ω·cm), and high decomposition temperature (>500°C) are simultaneously achieved for the composite films. These findings offer a facile strategy for the design of multifunctional TMMs, which hold great promising for application in electric devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hybrid particles are synthesized from boron nitride and barium titanate. • Composite films prepared by incorporating hybrid particles into cyanoethyl cellulose. • The composite exhibits a high dielectric constant of ∼ 44. • High thermal conductivity and breakdown strength are also achieved in the composite. Polymer dielectrics hold a great potential to be used in the field of power equipment and advanced electronics. However, their limited thermal conductivity fails to satisfy the imperative demand for heat dissipation in practical applications. Herein, we report a novel strategy to prepare multifunctional cyanoethyl cellulose matrix composite films by employing a hybrid filler of boron nitride nanosheets and barium titanate nanoparticles. The resultant composite films simultaneously exhibit high thermal conductivity (∼10.54 W/m·K), high dielectric constant (∼44), high electrical breakdown strength (>302 kV/mm), and low dielectric loss (∼0.01). The findings in this work enable broader application of polymer dielectrics in impulse power and energy storage devices. [ABSTRACT FROM AUTHOR]