Symbiotic strategy of Cu on CuFe2O4 realizing high-efficiency electromagnetic wave absorption

• Published in: Journal of colloid and interface science 2023-09, Vol.645, p.841-849
• Main Authors: Chang, Qing, Xie, Zijun, Shi, Bin, Wu, Hongjing
• Format: Article
• Language: English
• Subjects: Broadband absorption; Conduction loss; Cu/CuFe2O4; Interfacial polarization; Ultrathin thickness
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2023.04.141

[Display omitted] •Cu/CuFe2O4 composites with ant nest-like microstructure were synthesized for the first time.•The symbiosis of Cu on CuFe2O4 raise the intrinsic complex permittivity of pure CuFe2O4.•The effective absorption bandwidth is 6.32 GHz at 1.7 mm and RLmin is −48.81 dB.•Interfacial polarization and conductance loss are leading attenuation mechanism. Low complex permittivity and easy magnetic agglomeration prevent ferrites from achieving high-efficiency electromagnetic wave (EMW) absorption owing to the resultant narrow absorption bandwidth. Existing composition- and morphology-controlled strategies have made limited progress in fundamentally improving the intrinsic complex permittivity and absorption performance of pure ferrite. In this study, Cu/CuFe2O4 composites were synthesized using a facile and low-energy sol-gel self-propagating combustion, and the metallic Cu content was adjusted by changing the ratio of the reductant (citric acid) to the oxidant (ferric nitrate). The symbiosis and coexistence of metallic Cu with ferritic CuFe2O4 increases the intrinsic complex permittivity of CuFe2O4, which can be regulated by changing the metallic Cu content. Moreover, the unique ant-nest-like microstructure overcomes the issue of magnetic agglomeration. Because of the favorable impedance matching and strong dielectric loss (interfacial polarization and conduction loss) provided by the moderate metallic Cu content, S0.5 concurrently displays broadband absorption with an effective absorption bandwidth (EAB) of 6.32 GHz at an ultrathin thickness of 1.7 mm and strong absorption relying on minimum reflection loss (RLmin) of −48.81 dB at 4.08 GHz and 4.0 mm. This study provides a new perspective for improving the EMW absorption performance of ferrites.