Constructing hierarchical hollow flower-like MoO2/CoNi/NPC microspheres via water-in-oil system assisted supramolecular self-assembly for high-efficient electromagnetic wave absorption

Abstract

Starting from the composition combination and structural design of materials, the novel high-efficiency absorber can be exploited. Herein, we constructed hollow flower-like MoO2/CoNi/NPC microspheres by virtue of supramolecular self-assembly in water-in-oil system and carbonization. The study found that when the mass ratio of the phosphomolybdic acid and dopamine hydrochloride was 3:4, and the oil phase solvent was glycol, microspheres presented outstanding electromagnetic wave (EMW) absorption performance. Its minimum reflection loss (RLmin) value was − 54 dB and the effective absorption bandwidth (EAB) was 4.72 GHz at 1.97 mm with the filling ratio of 35 wt%. When the thickness was only 1.7 mm, the widest EAB was up to 6.48 GHz (11.52–18 GHz), covering the entire Ku-band. The excellent EMW absorption performance was mainly attributed to the multiple scattering and enhanced impedance matching caused by the 3D flower-like hollow structure, as well as the strong polarization loss induced by the double-layer structure and Schottky contact. We also utilized the radar cross section (RCS) analysis method to simulate and calculate electromagnetic (EM) scattering performance of aluminum metal plates with absorbing coatings. The analysis results further manifested that MoO2/CoNi/NPC could be used as excellent absorber.