Constructing\nNi₁₂P₅/Ni₂P Heterostructures to Boost Interfacial Polarization\nfor Enhanced Microwave Absorption Performance

Abstract

Heterostructures\nwith a rich phase boundary are attractive for surface-mediated microwave\nabsorption (MA) materials. However, understanding the MA mechanisms\nbehind the heterogeneous interface remains a challenge. Herein, a\nphosphine (PH₃) vapor-assisted phase and structure engineering\nstrategy was proposed to construct three-dimensional (3D) porous Ni₁₂P₅/Ni₂P heterostructures as microwave\nabsorbers and explore the role of the heterointerface in MA performance.\nThe results indicated that the heterogeneous interface between Ni₁₂P₅ and Ni₂P not only creates sufficient\nlattice defects for inducing dipolar polarization but also triggers\nuneven spatial charge distribution for enhancing interface polarization.\nFurthermore, the porous structure and proper component could provide\nan abundant heterogeneous interface to strengthen the above polarization\nrelaxation process, thereby greatly optimizing the electromagnetic\nparameters and improving the MA performance. Profited by 3D porous\nheterostructure design, P400 could achieve the maximum reflection\nloss of −50.06 dB and an absorption bandwidth of 3.30 GHz with\nan ultrathin thickness of 1.20 mm. Furthermore, simulation results\nconfirmed its superior ability (14.97 dB m² at 90°)\nto reduce the radar cross section in practical applications. This\nfinding may shed light on the understanding and design of advanced\nheterogeneous MA materials.