Interface-engineered decoupled conductivity and relaxation: Synergistic modulation of Debye-parameters in N-doped SiO 2 /MXene broadband wave-absorbing materials

Abstract

The development of Ti₃C₂T_x MXene-based electromagnetic wave-absorbing materials faces a persistent challenge in balancing conductivity loss and polarization relaxation. To resolve this conflict, we propose an "interface engineering - Human-Computer Interaction (HCI)" strategy to regulate the evolution of permittivity and decouple the interdependency between conductivity (σ) and relaxation time (τ). First, by integrating the Debye relaxation model and transmission line theory into Python-based interactive modules, an HCI framework is established that quantitatively guides the optimization of permittivity trends and provides feedback on intrinsic Debye-parameter variations. Subsequently, guided by these theoretical optimizations, nitrogen-doped SiO₂-coated Ti₃C₂Cl_x MXene composites (SMX) are prepared via interface engineering. The insulating SiO₂ layer suppresses excessive σ while introducing heterogeneous interfaces that prolong τ. Meanwhile, the surface heterogeneous dipole generated by nitrogen-doping induces a hysteresis of τ. Consequently, this theory-guided design enables the optimized SMX-S2-N1 to achieve a 5.2 GHz effective absorption bandwidth, overcoming the inherent limitation of narrow absorption bandwidth in MXene single-component materials. This study not only addresses the restricted absorption bandwidth of monolithic MXenes but also offers a mechanistic understanding of dielectric loss through Debye model analysis, bridging semi-empirical design principles with theoretical frameworks.