Abstract: The proliferation of advanced electronics and devices has led to significant electromagnetic interference and pollution, resulting in heightened interest in electromagnetic interference (EMI) shielding materials in recent years. Carbon foam, as a typical porous carbonaceous material, demonstrates significant potential as an innovative EMI shielding material owing to its lightweight nature, exceptional porosity, flexibility, favorable processability, and environmental sustainability. Nonetheless, the configuration of carbon atoms within the carbon foam is significantly disordered, leading to its intrinsic conductivity being comparatively low. Consequently, its shielding efficacy cannot meet the standards required for commercial EMI materials. Herein, we propose a hierarchical engineering strategy to construct a carbon foam composite with high shielding efficacy. Specifically, the FeCo nanoparticles and carbon layer are concurrently integrated into the carbon foam matrix to modulate its magnetic characteristics and conductivity. The results demonstrate that the carbon-coated FeCo/carbon foam composite achieves a shielding effectiveness (SE) of 24 dB in the X-band, signifying a 240 % improvement compared to the pristine carbon foam. Simultaneously, the composite also exhibits superior multifunctionalities involving flexibility, Joule heating, and hydrophobicity. This study provides a facile and effective routine to regulate the shielding efficacy of EMI shielding materials.

Key words: FeCo nanoparticles, Carbon layer, Electromagnetic shielding, Composite, Multifunctionality