Preparation Of MXene By Molten Salt Method And Its Application In Electromagnetic Absorption

In the era of digital information,especially the popularization of 5G,the demand for wireless co mmunication in remote office and smart home is getting higher and higher,and the increasingly serious electromagnetic wave（EM）radiation generated by electronic equipment will cause serious electromagnetic wave enviro nmental pollution,and even potential human safety hazards.The key to solving electromagnetic wave pollution is to develop efficient electromagnetic wave absorbing materials.MXenes are a new type of two-dimensional nanomaterials with high electrical conductivity and good dielectric loss properties,and they can be modified based on their abundant surface functional groups,such as-OH,-O,-F,etc.The previous etching method mainly etched the"A"layer elements of the MAX phase material by HF,which has a great risk of enviro nmental pollution and operational safety.The"A"layer elements of the MAX phase material are etched by the molten salt method,which is safer and more enviro nmentally friendly.In this paper,high-efficiency electromagnetic wave absorbing materials are prepared by molten salt etching method,and the influencing factors such as loss capacity or mechanism,impedance matching,structural characteristics,and synergy are investigated.The main work of this paper is as follows:（1）Ti₃AlC₂was first etched by CuCl₂molten salt to obtain Cu-doped Cu-Ti₃C₂T_xMXene with"accordion"structure.Subsequently,the Cu-Ti₃C₂T_x/Fe₂O₃/PAN hollow fiber composite material with dual loss capability was prepared by coaxial electrospinning technology.The minimum reflection loss of this material is-27.37 d B（5.5 mm,6.01 GHz）,and the maximum effective absorption bandwidth is 5.92 GHz（2.5 mm thick）.（2）On the basis of CuCl₂etching MAX,Ti₃AlC₂was further etched with Co Cl₂molten salt,and Co-doped Co-Ti₃C₂T_xMXene was obtained,which made the non-magnetic MXene magnetic,and also had double loss characteristics.Co-Ti₃C₂T_x/Fe₂O₃/PAN hollow fiber composites prepared by coaxial electrospinning technology are stronger than Cu-Ti₃C₂T_x/Fe₂O₃/PAN hollow fiber composites in electromagnetic absorption performance,which is due to the improvement of the dielectric loss and magnetic loss capabilities of Co-Ti₃C₂T_x/Fe₂O₃/PAN hollow fiber composites,and better impedance matching and synergy.The obtained Co-Ti₃C₂T_x/Fe₂O₃/PAN hollow fiber composite has a minimum reflection loss of-54.62 d B（3.5 mm,9.86 GHz）and a maximum effective absorption bandwidth of 6.39 GHz（2.5 mm thick）.And the 3.5 mm thick Co-MFP₂-1 and Co-MFP₂-2 samples can effectively cover the entire X-band,this shows that it has broad application prospects.