The 'two birds with one stone' strategy of flower-like multi-shell hollow microsphere/boron nitride composite achieves dual functionalities of efficient microwave absorption and excellent thermal management

Electronic devices not only face electromagnetic interference issues but also must address challenges such as performance degradation and reduced reliability caused by heat accumulation. Therefore, the development of dual-functional microwave absorbing materials (MAMs) that possess both efficient microwave absorption and excellent thermal management performance has become a crucial and urgent material science issue to be addressed. This study successfully fabricated flower-like multi-shell hollow microsphere/boron nitride (FMSHS/BN) composites through a combined strategy of surface modification, electrostatic self-assembly, and sequential templating. The SEM and TEM images of the FMSHS/BN-6 (the BN content is 60 mg) reveal that FMSHS is uniformly distributed between the BN layers, effectively mitigating the issue of local impedance mismatch caused by agglomeration. As a result, the FMSHS/BN-6 exhibited exceptional microwave absorption performance, achieving a minimum reflection loss (RLmin) of -61.73 dB and a maximum effective absorption bandwidth (EABmax) of 5.60 GHz. Meanwhile, the thermal conductivity of the composite reached 3.87 W/(m·K), representing a 921% improvement compared to that of pure FMSHS (0.42 W/(m·K)). These results demonstrate that the FMSHS/BN-6 realizes the synergistic integration of efficient thermal management and outstanding microwave absorption via a "two birds with one stone" design strategy, showing great potential for addressing thermal accumulation and high-frequency electromagnetic interference in electronic devices.