Construction of core-shell BN-OH@Fe3O4@PAn nanocomposite with ultra-wide microwave absorption and efficiency thermal management

As electronic device integration and power density increase, materials must have brilliant microwave absorption properties and thermal conductivity to solve electromagnetic wave pollution and thermal management problems. In this work, we attempt to construct core-shell hydroxylated boron nitride nanosheets (BN-OH) @Fe 3 O 4 @PAn (BFeA) nanocomposites by chemical synthesis and in-situ growth design. The excellent magnetic properties of Fe 3 O 4 and the good electrical conductivity of PAn can form magnetic loss and electrical loss centers to play a synergistic effect in improving microwave absorption capacity. Meanwhile, with the wave-transmitting material BN-OH as the core, the electromagnetic waves can be reflected multiple times within the absorber, which further enhances the microwave absorption capability of BFeA. As a result, the minimum reflection loss (RL min ) of the composites can reach − 49.85 dB at 11.36 GHz, and the effective microwave absorption bandwidth (RL<−10 dB, EAB) is close to 8 GHz (8.5–16.5 GHz) at a thickness of 3 mm. Simultaneously, to improve the thermal conductivity (TC) of the BFeA and reduce the interfacial thermal resistance, we use hydroxyl and dopamine as the interface linking agent at the interfaces of BN-OH and Fe 3 O 4 , and Fe 3 O 4 and PAn, respectively. In this case, the TC of BFeA-2 reaches 0.98 W (m K) −1 at a total BN–OH content of only 13 wt. %, nearly 4 times that of the raw material (Fe 3 O 4 ). This work can provide a reference for developing materials with dual functions of thermal management and microwave absorption.