Core–Shell rGO‐BN Heterostructures Endowing Polybutadiene Composites with High Thermal Conductivity and Efficient Microwave Absorption

Abstract The continuous miniaturization and high integration of electronic devices have intensified heat dissipation and electromagnetic interference issues while also limiting the simultaneous application of thermal interface and microwave absorbing materials. Thus, developing interface materials with both high thermal conductivity and efficient microwave absorption has become crucial. Herein, a core–shell rGO‐BN heterostructure filler is reported with both high thermal conductivity and efficient microwave absorption performance, which is fabricated through the self‐assembly of polydopamine‐coated spherical boron nitride (BN) and graphene oxide (GO) and followed by thermal reduction. The rGO‐BN is used as thermally conductive/microwave absorption filler and blended with boron nitride nanosheet (BNNS) and polybutadiene (PB) to prepare rGO‐BN/BNNS/PB composites. When the mass fractions of rGO‐BN and BNNS are 45 and 13 wt.%, respectively, the rGO‐BN/BNNS/PB composites exhibit thermal conductivity of 5.94 W m ⁻¹ K ⁻¹ , minimum reflection loss of −50.10 dB (3.9 mm, 8.42 GHz), and effective absorption bandwidth of 5.25 GHz (2.7 mm, 10.70–15.95 GHz), surpassing the current state of the art. This work provides fresh perspectives for overcoming the trade‐off between high thermal conductivity and excellent microwave absorption.