Ni₂P−Cu₃P/CNTs Nanocomposites with Porous Structures for Broadband and Wide-Angle Microwave Absorption

Designing dielectric absorber materials with wideband absorption, wide-angle performance, and lightweight characteristics remains a significant challenge. Inspired by the porous structure of volcanic rock, this study employed a simple one-step hydrothermal method and bubble assistance to synthesize micro/mesoporous Ni2P−Cu3P binary nanophosphides, which were then enhanced with CNTs to create a three-dimensional mesh structure. The porous structure of the Ni2P−Cu3P nanocomposite not only facilitates the formation of rich heterogeneous interfaces on the material surface, inducing lattice defects but also enhances interface polarization due to the uneven surface charge distribution of the pore structure. As a result, at a filling rate of only 10%, Ni2P−Cu3P/CNTs achieved an effective absorption bandwidth of 6.6 GHz with a thickness of 2.4 mm. Furthermore, this nanocomposite exhibited outstanding absorption performance within a wide oblique incidence range of 0−67° for transverse electrical (TE) mode and 0−75° for transverse magnetic (TM) mode. Notably, at reflection loss levels of −5 and −10 dB, the maximum effective oblique incidence angles reached 80° and 67° for TE and TM modes, respectively. These studies underscore the exceptional wide-angle and broadband absorption capabilities of Ni2P−Cu3P/CNTs nanocomposite materials even at extremely low filling rates, making them highly suitable for designing lightweight, broadband, and polarization-insensitive absorbers.