Simplifying the technology for regulating dielectric properties and enriching electromagnetic loss mechanisms of layered electromagnetic wave (EMW) absorption materials still faces challenges. Herein, we propose a simple and eco-friendly sieving strategy to control the lateral size (3–50 μm) of multilayered SiP₂ flakes for regulating dielectric constants. Moreover, hierarchical-structured 2D SiP₂@0D Ni nanoparticles/1D Ni chains low-dimensional aggregates are in-situ constructed on SiP₂ flakes via a two-step hydrothermal method to enhance interfacial polarization and electromagnetic synergistic effects. When the lateral size was controlled at 11 μm (SiP₂-300), the intrinsic SiP₂ exhibits strong reflection loss (RL) value of −38.9 dB at 1.7 mm. Notably, the construction of 2D/0D/1D SiP₂@Ni not only maintains a strong RL of −40.1 dB, but also shifts the corresponding absorption frequency from original Ku-band (11.8 GHz) to C-band (7.2 GHz). More importantly, the effective absorption bandwidth is broadened from 2.9 GHz to 4.1 GHz benefiting from the construction of electromagnetic synergy networks. Additionally, the radar cross section (RCS) value (29.14 dB⸱m²) evaluated by the computer simulation technology (CST) results for SiP₂@Ni–S2 confirm the excellent dissipation ability. This study provides a new strategy for the application of layered absorbers with low-frequency, broadband and adjustable EMW properties.

MXene-based absorbers have shown promising application prospects because of their sophisticated structural design and clever material composites. However, the intrinsic MXene materials themselves have not achieved significant breakthroughs in microwave absorption (MA) performance. Therefore, the development of novel and efficient pure MXene absorbing materials is imperative to address inherent mismatches in electromagnetic parameters, highlighting the urgent need in this area. Here, a straightforward strategy involving etching time modulation is proposed to customize the electromagnetic wave (EMW) absorption properties of delaminated Mo₂CT_x MXene. The impact of varying etching degrees on the EMW absorption capabilities of Mo₂CT_x MXenes was systematically investigated through controlled etching durations of Mo₂Ga₂C MAX phase. Among them, the sample etched for 12 h achieved an effective absorption bandwidth (EAB) of 4.4 GHz at an ultrathin thickness of 1.3 mm, and the strongest reflection loss (RL) value was as high as −60.7 dB when the sample etching time was increased to 24 h. The improvement in absorbing performance was attributed to the dielectric loss and polarization process induced by terminal functional groups and surface-rich defects, which optimized impedance matching. This work establishes that intrinsic Mo₂CT_x MXene materials with superior absorbing properties outperform traditional pure MXenes, providing a strong basis for advancing Mo-based MXene absorptive materials.