Ti3C2Tx MXene/Y2O3/C composites for broadband EMW absorption through dielectric regulation and impedance matching optimization

Balancing dielectric attenuation and impedance matching is essential for developing efficient MXene-based EMW absorbers because an excessively developed conductive network may deteriorate impedance matching and hinder electromagnetic wave penetration. Herein, Ti 3 C 2 T x MXene/Y 2 O 3 /C composites were prepared through in situ solvothermal assembly followed by pyrolysis. By increasing the Ti 3 C 2 T x MXene feed fraction, the dielectric response and impedance-matching behavior of the composites were systematically regulated. Structural analyses confirmed the formation of crystalline Y 2 O 3 , carbonaceous domains, and MXene-based heterostructures with mesoporous features. The composites exhibited composition-dependent and non-monotonic absorption behavior. MY-3(Nominal MXene-to-precursor feed ratios of 2:5) composite delivered the strongest absorption intensity with a minimum RL of −49.4 dB, while MY-4(Nominal MXene-to-precursor feed ratios of 1:2) composite achieved the broadest EAB of 7.2 GHz. The enhanced absorption performance is attributed to the regulated conductive network, interfacial polarization at MXene/Y 2 O 3 /C heterointerfaces, dipole polarization from polar bonds and oxygen-containing groups, and improved impedance matching. Radar cross-section simulations further verified the scattering suppression capability of the optimized coatings. This work demonstrates that Y 2 O 3 /C-assisted dielectric regulation is an effective strategy for improving broadband absorption in MXene-based dielectric absorbing materials.