Synthesis And Microwave Absorption Properties Of Cu₉S₅-based Composites

Cu₉S₅ has the characteristics of high ion mobility,good electrical conductivity and easy preparation.The Cu₉S₅ materials prepared by hydrothermal method have the advantages of obvious lattice defects as well as controlled morphology.It is a potential candidate material for a new generation of microwave absorbing materials.In this work,three Cu₉S₅ materials with different morphologies and a series of porous sheet-like Cu₉S₅-based composites were prepared.XRD,SEM,TEM,XPS,FT-IR and Raman spectra were used to characterize the components and morphological structures of the materials,and a vector network analyzer（VNA）was used to test the electromagnetic parameters of the samples.The results are as follows.（1）Cu Cl₂.2H₂O,H₂NCSNH₂,and Na₂S.9H₂O were used as raw materials.Three different morphologies of Cu₉S₅ materials,such as flakes,porous flakes and polyhedra,were prepared by hydrothermal method.The effects of the different morphologies on the microwave absorption properties were investigated.The results show that the crystallization effect and morphology of the three materials differ significantly,and the porous flake Cu₉S₅ is the most valuable for further study due to the synergistic effect of multiple loss paths,which gives the material excellent performance and a wide absorption bandwidth of 5.2 GHz at 1.9 mm.（2）The hollow VO₂ microspheres were prepared from V₂O₅ and C₂H₂O₄·2H₂O,and bi-semiconductor heterojunction Cu₉S₅@VO₂ composites were prepared hydrothermally from Cu Cl₂.2H₂O and H₂NCSNH₂.The effects of the addition amount of VO₂ and the microstructure on the microwave absorption properties of the materials were investigated.The results show that the minimum reflection loss(RL_min)of Cu₉S₅@VO₂ composites reaches-56.98 d B and the EAB at 2.5 mm is 6.88 GHz when the VO₂ addition is 0.12 g.This is attributed to the unique microstructure,the good chemical bonding state and the synergistic effect of the composite heterojunction.The preparation of two-semiconductor heterojunction composites is an effective strategy to construct broadband,tunable and efficient microwave absorbers.（3）The magnetized 3D flower-like Cu₉S₅/Zn Fe₂O₄ composites were prepared by a simple hydrothermal method using Zn（NO₃）₂.6H₂O,Fe Cl₃.6H₂O,CO（NH₂）₂,and Cu₉S₅as raw materials.The effects of Cu₉S₅ addition and microscopic morphology on the microwave absorption properties of the materials were investigated.The results show that the composites have excellent electromagnetic absorption performance with RL_minof-54.38 d B and EAB of 5.92 GHz at 1.6 mm when Cu₉S₅,Zn（NO₃）₂.6H₂O,and Fe Cl₃.6H₂O are added in the molar ratio of 1:2:4.The introduction of Zn Fe₂O₄ imparts magnetic loss capability to the composites.The unique 3D flower-like Cu₉S₅/Zn Fe₂O₄ composite imparts a variety of loss mechanisms to the material,which greatly improves the impedance matching characteristics of the material.Figures[30]Tables[6]References[102]...