Preparation And Electromagnetic Wave Absorption Properties Of Two-dimensional Ti₃C₂T_x-based Composites

With the widespread use of mobile communication electronic devices,the problem of electromagnetic wave pollution has become more and more serious.Meanwhile,the national defense industry has also put forward an urgent need for stealth technology.Therefore,it is a great significance to synthesis electromagnetic absorption materials with high efficiency and light weight.In this thesis,the interlayer space of two-dimensional laminated structure Ti3C2Tx MXenes materials is controlled by HF solution concentration and reaction time.Then,it is combined with other electromagnetic wave absorption materials by advanced material preparation methods to achieve the purpose of simultaneously regulating structure and component.Furthermore,the effect of the structure and component of the composite on the electromagnetic wave absorption performance and the absorption mechanism were investigated.The specific research contents and results are as follows:(1)Preparation of two-dimensional laminated structure Ti3C2T.MXenes materials with larger interlayer space and thin Ti3C2Tx MXenes sheets.The microstructure of the Ti3C2Tx MXenes material is tuned by changing the concentration of the HF solution and the reaction time.The optimum process for preparing Ti3C2Tx MXenes materials was prepared with large interlayer space and thin Ti3C2Tx MXenes sheets,then characterized its electromagnetic parameters.Due to the special laminated structure,good impedance matching,inherent defects and functional groups,the Ti3C2Tx MXenes material exhibits excellent electromagnetic wave absorption performance with a minimum reflection loss value of-36.7 dB.Its effective absorbing band(RL<-1OdB,90%of electromagnetic waves are absorbed)is up to 4 GHz.(2)Syntheis of two-dimensional laminated structure Ti3C2T,MXenes/carbon sphere composites.Nano-carbon spheres were formed at the interlayer and surface edges of two-dimensional laminated structure Ti3C2Tx MXenes by prolonging the reaction time.The Ti3C2Tx MXenes/carbon sphere composites was innovatively obtained,and the composite formation mechanism of amorphous carbon spheres grown on the surface of the Ti3C2Tx MXenes was proposed,which explained the formation process of carbon spheres.Compared with Ti3C2Tx MXenes materials,this composite exhibits excellent electromagnetic wave absorption performance with a minimum reflection loss value of-54.67 dB and an effective absorption band(RL<-10dB,90%electromagnetic wave)can be adjusted by controlling the thickness of its absorption coating thickness.The excellent electromagnetic wave absorption properties of Ti3C2Tx MXenes/carbon sphere composites is attributed to good electrical conductivity,interfacial polarization,multiple reflection,scattering electromagnetic waves,and special layered structures.(3)Synthesis of two-dimensional laminated structure Ti3C2Tx MXenes/TiO2 composites.The Ti3C2Tx MXenes/TiO2 composites were successfully obtained by annealing two-dimensional laminated structure Ti3C2Tx MXenes materials at different temperatures.The electromagnetic wave absorption properties of two-dimensional laminated structure Ti3C2Tx MXenes/TiO2 composites were investigated.It can be found that the electromagnetic wave absorption performance of the Ti3C2Tx MXenes/TiO2 composite is better than that of the Ti3C2Tx MXenes material.In addition,the electromagnetic wave absorption properties of the Ti3C2Tx MXenes/TiO2 composite can be controlled by adjusting the content of TiO2 in the composites.The Ti3C2Tx MXenes/TiO2 composite has a minimum reflection loss value of-40.07 dB,and its effective absorbing band(RL<-10 dB,90%of electromagnetic waves absorbed)can be adjusted by changing the thickness of the absorbing coating.In a word,it can be seen that by regulating the microstructure of the two-dimensional laminated structure Ti3C2Tx MXenes material and introducing the second phase in the two-dimensional laminated structure Ti3C2Tx MXenes material,the electromagnetic wave absorption performance can be significantly improved.Therefore,this thesis provides theoretical and practical guiding significance for the design of electromagnetic absorption materials with excellent absorption performance.