In-situ reduction of AgNPs on MXene surfaces for synthesis of efficient thermally conductive composites with powerful electromagnetic shielding capabilities.

Thermally conductive materials are crucial for stable operation of integrated circuits, and there is high interest in improving the thermal conductivity of MXene. This study develops a facile method to enhance the chelating and reducing abilities of MXene towards metal ions by coating a thin layer of polydopamine onto the MXene surface, followed by decoration of silver nanoparticles on the nanosheet surface through in-situ reduction. Naturally abundant nanocellulose fibers were used as the matrix, and continuous thermal pathways were constructed between the fibers by vacuum filtration of the prepared nanofillers. The essential role of AgNPs in providing efficient thermal conductive networks was analyzed using the finite element analysis software. The prepared composite films exhibited an in-plane thermal conductivity up to 7.31 W/m K and demonstrated superior temperature control in heat dissipation tests. At a filler mass fraction of 30 wt%, the average electromagnetic shielding effectiveness of the film with a thickness of 0.17 mm was measured to be 25.8 dB in the X-band, which exceeds the target value for commercial applications. The outstanding performance of the composite paper has demonstrated the great potential of silver-decorated MXene for widespread application in fields such as electronic devices, aerospace, and aviation. [Display omitted] [ABSTRACT FROM AUTHOR]