Manipulating Highly Ordered MXene Porous Composites by Directional Freezing for Absorption Effectiveness-Enhanced Electromagnetic Interference Shielding

Ti₃C₂T_x MXene, as a 2D conductive material, has broad application prospects in electromagnetic interference (EMI) shielding fields. Nevertheless, excessive conductivity will destroy impedance matching, resulting in serious electromagnetic wave secondary reflection pollution. Herein, we developed a kind of highly ordered MXene-based porous composite material (PCM) for absorption effectiveness-enhanced EMI shielding via introducing magnetic Co-C@multiwalled carbon nanotubes (MWCNTs) by directional freezing. Furthermore, sodium alginate was introduced to form hydrogen bonds, thereby enhancing the interaction between adjacent MXene nanosheets to increase the mechanical properties of the PCMs. Co-C@MWCNTs in the PCMs can construct a three-dimensional conductive network with MXene nanosheets and promote electron migration and transition, which provide magnetic loss and hence promote the absorption of electromagnetic waves. As expected, the PCMs exhibit a highly ordered and long-range order porous structure. Additionally, when MXene and Co-C@MWCNTs are in a mass ratio of 1:3, the MXene/sodium alginate (SA)/Co-C@MWCNTs PCMs deliver an ultrahigh conductivity of 849 S m^-1, a high EMI shielding efficiency of 41.7 dB, and a compressive stress of 50.9 kPa under 80% strain. This work offers a novel approach to construct high-strength and high-EMI shielding materials with a highly ordered pore structure based on enhanced absorption effectiveness.