Biaxially Oriented High-Thermal-Conductivity Electromagnetic Wave Absorber Based on Interlayer Phonon Bridge Construction

Electronic packaging materials that exhibit favorable electromagnetic wave absorption (EMA) and thermal conductive features are critically important for the protection of growing high-power advanced electronics. However, existing bifunctional materials emphasize only single EMA performance and suffer from severely insufficient thermal conductivity. Thus, it remains an enormous challenge to develop a highly thermally conductive electromagnetic absorber. Herein, inspired by nacre shell, we propose phonon bridges embedding a layered skeleton-densification strategy to prepare biaxially oriented SiC@BN/WPU composite for integrating efficient phonon transport with strong electromagnetic absorption. Benefiting from the deep modulation of dielectric features and the construction of a compact biaxial thermal pathway, the resulting B-SCBW material delivers excellent electromagnetic features with minimum reflection loss values of −46.29 dB and an effective absorption bandwidth of 5.02 GHz, and outstanding through-plane and in-plane thermal conductivity of 6.22 W m–1 K–1 and 9.27 W m–1 K–1, respectively. Besides, the evolutionary correlation from structure to performance is also systematically elucidated. This work proposes an efficient materials-structural-function strategy to balance superior electromagnetic and high thermal conductive attributes, providing valuable experience for the fabrication of electronic packaging materials integrating electromagnetic protection and thermal management.