Electromagnetic shielding and thermal insulation hydrogels were constructed based on covalent organic skeleton COF and Ti ₃ C ₂ T _<i>x</i> MXene

Abstract With the widespread popularity of electronic equipment and rapid development of wireless communication technology, electromagnetic shielding materials possessing thermal insulation properties can effectively block electromagnetic radiation for ensuring normal operation of electronic equipment and human health, while providing heat insulation to improve energy efficiency and protect equipment from high temperatures. In this study, we employ covalent organic skeleton (COF) to optimize Ti 3 C 2 T x MXene layers and successfully prepare MXene@COF heterostructures. This structure maintained the unique two‐dimensional architecture of Ti 3 C 2 T x MXene while preventing aggregation and self‐stacking of MXene nanosheets through the outer COF layer. The modification increases material porosity and significantly enhances electrical conductivity. We incorporated the heterostructure into acrylamidegelatin hydrogels and controlled shielding efficiency by varying COF content. Results demonstrate that the MXene@COF‐based hydrogel (15 mm p‐phenylenediamine) exhibits high toughness, strong electromagnetic shielding capability, infrared stealth performance, and thermal insulation properties. In the X‐band, mechanical tests show only 3 mm in thickness and 0.90 wt% MXene@COF content, electromagnetic shielding efficiency (EMI SE) of the material is as high as 37.52 dB, and the average total electromagnetic shielding (SE T ) is 32.01 dB, the compressive stress is 20.85 MPa, the water content is 79.04%, and the electrical conductivity is 1.22 S m −1 . These finding soffer new possibilities for developing COF‐based electromagnetic shielding materials.