An electronic-structure–driven mechanism for enhanced electromagnetic wave absorption in p-block nonmetal–doped MXenes

Dielectric polarization optimization and conductive loss modulation are widely employed strategies for achieving lightweight and broadband electromagnetic (EM) absorption. However, a unified mechanistic understanding that explicitly correlates polarization and conductive loss with the underlying electronic structure remains lacking, rendering their synergistic regulation largely empirical. Herein, a combined theoretical–experimental framework is established to elucidate an electronic-structure–driven attenuation mechanism, using p-block nonmetal–doped MXenes as a model system. First-principles calculations reveal that selective bonding between p-block elements and Ti₃C₂T_x induces charge redistribution, strengthens Ti–X interactions, and generates localized polarization centers, thereby activating coupled dipolar, interfacial, and defect-related polarization while simultaneously tuning conductive loss. Guided by this mechanism, Ti₃C₂T_x MXenes doped with representative p-block elements (B, N, P, and S) are synthesized, achieving minimum reflection losses of −60.5 dB (B), −52.9 dB (N), −53.8 dB (P), and −54.8 dB (S). For same-period dopants, increasing electronegativity broadens the effective absorption bandwidth without altering the underlying dissipation mechanism, with N- and S-doped Ti₃C₂T_x achieving bandwidths of up to 5.24 and 4.56 GHz. The strong agreement between theory and experiment establishes a universal electronic-structure–modulation pathway for regulating polarization and conductive loss in MXenes, providing theoretical guidance for designing lightweight, high-performance EM absorbers.