Robust Multisource Built-In Electric Fields in High-Entropy MXene-Derived Nitrides for Efficient Electromagnetic Wave...

High-entropy MXene derivatives offer new opportunities for electromagnetic wave absorption materials by introducing structural and electronic complexity, whereas the construction of robust multisource built-in electric fields (BIEF) to enhance electromagnetic attenuation remains a significant challenge. Herein, we designed high-entropy MXene-derived multicomponent nitrides for efficient electromagnetic absorption via sequential oxidation and nitridation of the TiVCrMoC₃T_x precursor. The high-entropy-driven phase transformation induces complex phases and microstructures involving multiple metallic nitrides and narrow-gap semiconducting nitrides with abundant heterogeneous interfaces and structural defects. Combined electron holography and theoretical calculation reveal the presence of multisource BIEF derived from abundant short-range dipoles, stable long-range dipoles, and work-function-driven interfacial charge redistribution. Various dipoles construct robust BIEF networks with stable polarization oscillations and a rapid dielectric response over a broad frequency range. Benefiting from the synergistically enhanced dipole polarization, conduction loss, and optimized impedance matching, the ON-TiVCrMoC₃T_x achieved a minimum reflection loss of -52.02 dB and an effective absorption bandwidth of 4.8 GHz at a thickness of only 2.0 mm. This work not only sheds light on the origin and regulation of BIEF for enhanced electromagnetic absorption but also provides an effective strategy to construct multisource BIEF for the design of electronic, optoelectronic, and sensing devices.