Tunable lateral size and hierarchical structure SiP₂@Ni low-dimensional aggregates for enhanced electromagnetic wave absorption

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.