Microwave-assisted Preparation Of Bi₂S₃ Composite Materials And Study Of Their Electromagnetic Propertie

With the rapid development of electronic information technology,the widespread use of electromagnetic wave brings environmental pollution and other problems.Therefore,efficient absorbing materials are urgently needed to solve problems such as electromagnetic wave pollution.The requirement for an ideal electromagnetic absorbing material includes thin thickness,wide band,light weight,and strong absorption performance.In this work,the preparation of Bi₂S₃ composite and its electromagnetic wave absorption performance were studied,and the influence of different Bi₂S₃ content,composition and structure of composite on the absorption of electromagnetic wave was discussed,and the electromagnetic wave loss mechanism of composite was analyzed（1）A novel multilayer Bi₂S₃/Ti₃C₂T_x composite was successfully synthesized using a solvothermal method.By adjusting the Bi and S contents,the dielectric parameters of the composite were regulated.The rod-like Bi₂S₃ was grown in situ on the 2D Ti₃C₂T_x phase surface as well as between the lamellar layers to construct the multi-polarization interface,so as to obtain the composite materials with outstanding performance of electromagnetic wave absorption.According to the testing results,the optimal reflection loss of the Bi₂S₃/Ti₃C₂T_x composite was-50.66 d B with the thickness of 1.11 mm,and the maximum effective absorption bandwidth was 3.89 GHz at 1.2 mm.The synergistic effect of the Ti₃C₂T_x multilayer structure and Bi₂S₃interface polarization is conducive to the multiple resonator reflections of the incident electromagnetic wave and the effective loss of electromagnetic wave at the polarization interface,which can significantly improve the electromagnetic wave absorption performance.（2）Because a large number of heterogeneous interfaces are formed in the composite material composed of multiple components,it is beneficial to enhance the interface loss effect of the composite material and improve the electromagnetic wave absorption performance of the composite material.In this section,Bi₂S₃/Bi/Ti₃C₂T_xcomposites with three components were designed and synthesized successfully.By regulating Bi and S contents,the electromagnetic wave absorption performance of composites prepared with different additive contents was studied.The results show that when the content of bismuth nitrate pentahydrate and thiourea is 0.1 mmol and0.15 mmol,respectively,the composite has an optimal reflection loss of-52.05 d B at a frequency of 5.89 GHz and a thickness of 3.2 mm.In addition,the composite has a maximum effective absorption bandwidth of 3 GHz（12.2-15.2 GHz）at a thickness of1.5 mm.（3）Bi₂S₃/CuS composites with flower-like structure were prepared by microwave solvothermal method.Because of its unique structure and excellent interface polarization loss and conduction loss,it has excellent electromagnetic wave absorption performance.The results show that the electromagnetic wave absorption performance of Bi₂S₃/CuS composites can be optimized by adjusting the addition content of Bi₂S₃and reaction time.When the content of Bi₂S₃ is 0.35g and the reaction time is 2 h,the composite has excellent absorbing properties.It has an optimal reflection loss of-66d B When the frequency is 11 GHz and the thickness is 2.19 mm.At the same time,the optimal effective absorption bandwidth is 3.9 GHz（14.1-18 GHz）at the thickness of1.5 mm.