Hierarchically Structured Composite Decorated with Core‐Sheath CoC@Carbon Fiber Felt: Exceptional Electromagnetic Interference Shielding and Applications in Thermal Management and Electro/Photo‐Thermal Conversion

In the microelectronics era, electromagnetic radiation and heat accumulation in electronic devices are urgent challenges requiring solutions, particularly through the use of structure-function integrated and lightweight materials for electromagnetic interference (EMI) shielding and thermal management. Hierarchically structured polyether-ether-ketone-based composites are prepared in this study by in situ deposition and dip coating using a simple and scalable method. Magnetic cobalt nanoparticles derived from magnetic metal-organic frameworks are deposited on carbon fiber felt featuring a macroscopic continuous conductive network. Next, a hybrid slurry is applied to connect the isolated fibers, which bridge the fiber gaps to create new electron and phonon transport channels, increasing the thermal conductivity (23.43 W m^-1 K^-1 in plane, 4.84 W m^-1 K^-1 through plane) for efficient heat dissipation. Owing to the stable 3D crosslinked network with high electrical conductivity (13 608 S m^-1), the composite offers ultra-high EMI shielding in the X-band (101.64 dB with stability in extreme environments), excellent Joule heating performance (220 °C at 4 V), and excellent photothermal conversion (94 °C at 500 mW cm^-2). This multifunctional composite material has great application prospects in precision electronic equipment.