One-dimensional Ag-CoNi nanocomposites modified with amorphous Sn (OH)2/SnO2 shells for broadband microwave absorption

High-performance microwave absorption absorbers play important roles in the fields of radar stealth, electromagnetic protection, and antenna technology. In this work, high aspect-ratio Ag nanowires were decorated with magnetic CoNi nanoparticles via a PVP-induced solvothermal method, and then amorphous Sn(OH)(2)/SnO2 shells were introduced through an in-situ oxidative hydrolysis method, successfully preparing Ag-CoNi@Sn(OH)(2)/SnO2 composites. The morphology and ingredient of composites were ascertained by SEM, TEM, XRD, EDX, and XPS. As Ag-CoNi nanocomposites are coated by Sn(OH)(2)/SnO2 shells, the minimum reflection loss value is decreased from -31.7 dB (10.1 GHz) to -37.8 dB (6.4 GHz), and the maximum effective absorption bandwidth is extended from 3.9 GHz (10.3-14.2 GHz) to 5.8 GHz (10.7-16.5 GHz). Analyses of electromagnetic parameters reveal the possible mechanisms, involving surface plasma resonance, conductive loss, interfacial polarization, dipole polarization, exchange resonance, eddy current effect, multiple reflection and scattering. Thus, Ag nanowires modified with CoNi nanoparticles and amorphous Sn(OH)(2)/SnO2 shells can effectively balance the impedance matching and attenuation capability. It is a new strategy to achieve broadband microwave absorbers. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

This study successfully prepared Ag-CoNi@Sn(OH)(2)/SnO2 composite materials, achieving a wide microwave absorption bandwidth and reduced reflection loss through modification of Ag nanowires. This new strategy is expected to play an important role in radar stealth and electromagnetic protection.