Building Thermal-Conduction Nanochannels in Composite Electromagnetic Interference Shielding Film for Electromagnetic Heat Management.

In the 6G era, miniaturized and highly integrated wearable communications devices require electromagnetic materials with efficient thermal-management capability to mitigate electromagnetic interference (EMI) and heat accumulation. Herein, we present a facile strategy for conducting electromagnetic heat by constructing directional thermal-conduction nanochannels within a layer-by-layer EMI shielding film. This composite film consists of polyacrylonitrile/boron nitride nanosheets@polydopamine nanofibers covered with an EMI layer based on MXene sheets. Compared with traditional materials in which the heat dissipates randomly, the one-dimensional fibrous structure can offer a directional heat dissipation pathway. Under high-power microwave irradiation, it exhibits significantly lower temperatures, ensuring robust and durable communication performance without overheating. The thin film (0.43 mm thickness) achieves an impressive specific surface shielding efficiency of 29,400 dB·cm·g at 18-24 GHz, with an EMI shielding effectiveness (SE) of 88 dB for its layer-by-layer structure counterpart. In addition, the flexible film maintains a high EMI SE after 10,000 bending times. Its lightweight, flexible, and thin design makes it suitable for robust applications in various environments. This EMI shielding and thermally conductive film provides rapid heat dissipation and effective signal shielding for wearable communication systems, showcasing the great potential for efficient thermal management in next-generation communication technologies.