Synergistic interfacial polarization in BO_xF_y-modified Ti₃C₂T_x MXene with in situ N-doped carbon for broadband microwave absorption

Pristine Ti₃C₂T_x MXene generally suffers from severe impedance mismatch arising from its excessive electrical conductivity, which fundamentally limits efficient electromagnetic wave (EMW) attenuation. Herein, an interfacial modulation strategy is proposed by integrating fluorinated boron oxide (BO_xF_y) nanophases and in situ derived N-doped carbon into a Ti₃C₂T_x MXene framework through a hydrothermal process. Distinct from conventional boron-containing modification, the introduced BO_xF_y species provide abundant polarization-active sites and tailor the local interfacial environment through the coexistence of B-O and B-F coordination, thereby improving dielectric polarization and impedance matching. Meanwhile, the in situ formed N-doped carbon establishes defect-rich conductive networks, enabling balanced conductive loss and dipolar polarization. More importantly, the synergistic coupling among BO_xF_y nanophases, N-doped carbon, and Ti₃C₂T_x MXene constructs abundant heterogeneous interfaces and multiscale conductive pathways, facilitating interfacial polarization and electromagnetic energy dissipation. As a result, the optimized BN(1:1)-MXene achieves a minimum reflection loss of −58.97 dB at 1.77 mm and an effective absorption bandwidth of 4.24 GHz. Furthermore, radar cross-section simulations demonstrate remarkable electromagnetic scattering suppression with a maximum reduction of 32.05 dB m² at normal incidence. This work highlights the synergistic effects of interfacial modulation on electromagnetic attenuation, offering a promising strategy for high-performance MXene-based EMW absorbers.