Facile Preparation Of In-situ Coated Ti₃C₂T_x-Ni_0.5Zn_0.5Fe₂O₄ Composites And Their Electromagnetic Performance

With the rapid development of electronic industry information,notebook computers,mobile phones,tablet computers and other mobile electronic devices have almost covered every family,and become an indispensable part of people's daily lives.However,with the rapid increase in the number of these wireless communication devices and high-frequency electronic devices,electromagnetic interference phenomena and electromagnetic pollution problems also become more and more serious.Therefore,around the design and development of the new electromagnetic shielding material,broaden the electromagnetic shielding material absorption frequency range,and lightweight research has become the world's scientists research focus.Ni-Zn ferrites have been considered promising candidates as EM absorbers owing to their appropriate permeability and permittivity,the high resistivity and narrow absorption bandwidth have limited their applications as EMI absorbers.In order to solve the above problems,this paper improves the electrical conductivity of ferrite materials by introducing new two-dimensional layered transition metal carbon or/and nitride(MXenes)with high conductivity,and improving the impedance matching of the composites.In this paper,Ti3C2Tx/Ni0.5Zn0.5Fe2O4 composites were prepared by coprecipitation hydrothermal method and coprecipitation method,and their phase,microstructure and electromagnetic properties were studied.Experimental results show:Ti3C2Tx MXenes will be oxidized synthesisedby high temperature hydrothermal at 180?,and formation of heterogeneous TiO2.The Ti3C2Tx/Ni0.5Zn0.5Fe2O4 composites were synthesized by hydrothermal synthesis at low temperature of 80? by adding low boiling point isopropanol as solvent and choicing Fe2+ as the iron source with strong reactivit,avioding the oxidation of the Ti3C2x MXenes.At the same time,Ni0.5Zn0.5Fe2O4 nanoparticles were in situ coating on Ti3C2Tx MXenes and inserted into Ti3C2Tx MXenes layers,and the Ti3C2Tx MXenes still maintain a intact two-dimensional layered structure after the end of the reaction.The electromagnetic performance results show that the introduction of a small amount of non-magnetic Ti3C2Tx MXenes has little effect on the magnetic properties of the composites,but has a great influence on the dielectric properties.The reflection loss of Ti3C2Tx/Ni0.5Zn0.5Fe2O4 composites shows that the reflectance increases with the increase of Ti3C2Tx MXenes content.When the Ti3C2Tx MXenes mass fraction is 5 wt.%and the thickness of the absorber is 6.5 mm,the minimum reflection loss of the composites is-33.6 dB(13.5 GHz)in Ku band.In addition,in order to further simplify the preparation process of composite materials,Ti3C2Tx/Ni0.5Zn0.5Fe2O4 composite was prepared by one-step coprecipitation method.The direct coprecipitation method avoids the oxidation of Ti3C2Tx MXenes,but the crystallinity of NiZn ferrite is very poor.Therefore,Ti3C2Tx/Ni0.5Zn0.5Fe2O4 composite was prepared by one-step coprecipitation oxidation method,Ni0.5Zn0.5Fe2O4 nanoparticles were in situ coating on Ti3C2Tx MXenes and inserted into Ti3C2Tx MXenes layers,and the Ti3C2Tx MXenes remained intact two-dimensional layered structure in composites.The Ti3C2Tx MXenes are not oxidized at low temperature with oxygen.When the mass faction of Ti3C2Tx MXenes is 5 wt.%and the thickness of the absorber is 6.5 mm,the minimum reflection loss of composite is-42.5 dB(12.5 GHz),the minimum reflection loss of composites material is up to-42.5 dB,and the effective absorption bandwidth is 3 GHz(12-15 GHz)in Ku band.In summary,the electrical conductivity,dielectric loss,impedance matching and high frequencies absorption performance of the Ti3C2Tx/Ni0.5Zn0.5Fe2O4 composites are improving by addition of Ti3C2Tx MXenes,and expand the effective absorption band.The possible absorption mechanism of Ti3C2Tx/Ni0.5Zn0.5Fe2O4 composites includes magnetic losses,dielectric losses,conductance losses,and multiple reflections and scattering between Ti3C2Tx MXenes layers.In this paper,a new type of MXenes/ferrite composites has been developed.The synthesis method is fast,simple and low cost,It will provide a theory and experimental reference for application of the new two-dimensional layered transition metal carbon and/or nitride MXenes/ferrite composites in microwave absorption fields.