Interfacial Engineered MXene Heterostructures for Broadband Electromagnetic Wave Absorption and Thermal Insulation.

The rational construction of multi-component heterogeneous interfaces is crucial for overcoming the inherent limitations of single-component microwave absorbers. This study designs a novel multi-component composite Ti3C2Tx-TiO2/nitrogen-doped carbon derived from MXene@polypyrrole. By employing an in situ polymerization-calcination temperature gradient design method, the oxidation degree of the MXene precursor and the carbonization process are precisely controlled, thereby adjusting the dielectric constant. The optimized composite exhibits excellent microwave absorption performance, achieving an effective absorption bandwidth (EAB, RL ≤-10 dB) of 6.89 GHz and a strong reflection loss of -57.27 dB at a thickness of 2.2 mm. Mechanistic studies reveal that excellent impedance matching and multiple polarization between multi-layer heterogeneous interfaces cooperate to establish a comprehensive microwave attenuation mechanism. Compared with the recently developed TiO2-based microwave absorbing materials, the EAB is significantly enhanced, successfully resolving the long-standing bandwidth-thickness contradiction in dielectric-dominant systems. Additionally, the thermal insulation property of the material makes it have the potential for practical application. This study provides new insights into the design of multifunctional electromagnetic wave absorbers.