In-Situ CuNPs Reduction on MXene for High-Thermal-Conductivity Composite Films with Exceptional EMI Shielding and Photothermal Conversion

The rapid advancement of 5G communication technology necessitates enhanced performance in electromagnetic interference (EMI) shielding and thermal management materials. We fabricated multifunctional nacre-like MXene@CuNPs(MSC)composite films via intermittent filtration and in situ reduction. The resulting composite film exhibited a high in-plane thermal conductivity of 47.6 W m –1 K –1 and demonstrated superior thermal management capability in heat dissipation tests. Containing 3.1 wt % Cu and with a thickness of 0.04 mm, the film achieved an average EMI shielding effectiveness (SE) of 64 dB within the X-band (8.2–12.4 GHz). Calculations based on the effective medium theory (EMT) elucidated the critical role of Cu nanoparticles (CuNPs) in establishing an efficient thermal conduction network. Owing to the CuNPs acting as thermal bridges, the interfacial thermal resistance within the composite film decreased by 35.6%. Furthermore, the MSC composite films exhibited rapid-response photothermal behavior. Upon irradiation with a light power density of 200 mW cm –2, the surface temperature of the MSC 3.1 film rapidly reached 101 °C. The outstanding performance of this composite film underscores the broad application potential of Cu-modified MXene in electronic devices and related fields.