Regulated electron migration in sandwich-like m-Ti3C2/Fe3O4 composites derived from electrostatic assembly boosted electromagnetic wave absorption

Magnetic MXene-based composites have been extensively developed for highly effective electromagnetic (EM) wave absorption. However, previously reported studies neglected the influence of regulating primary dissipation sources and electron migration on absorption performance. This is probably due to the fact that the present modification methods frequently severely oxidize MXenes, obliterating the electron migration pathway. Here, a facile strategy is developed to create sandwich-like m-Ti3C2/Fe3O4 (MTF) composites by electrostatic assembly. The room temperature assembly process prevents oxidation and safeguards the in-plane electron migration path of m-Ti3C2. This makes it possible to reveal the mechanism by which increased Fe3O4 content inhibits electron migration, lowers attenuation capacity, and leads to increasing impedance-matching thickness. More importantly, we provide the first explanation of the absorption band transfer phenomenon. Additionally, at a thickness of 2.96 mm, the as-prepared MTF composites exhibit exceptional EM wave absorption capacity, reaching -77.5 dB with an effective absorption band of 3.0 GHz. The comprehensive insight presented in this work offers a solid theoretical foundation for an in-depth understanding of the influence of electron hopping behaviors on electromagnetic characteristics and, consequently, EM wave absorption performance, which further offers an essential roadmap to fabricate high-performance absorbers.