Honeycomb Structured Ti₃C₂T_x Materials For Excellent Electromagnetic Interference Shielding Properties

Ti₃C₂T_x MXene is a 2D material material with many advantages such as high conductivity and large specific surface area.It has excellent application prospects in the field of electromagnetic wave shielding.Ti₃C₂T_x MXene flakes usually tend to be stacked when separated from the dispersion,which makes it difficult to exert its advantages.Therefore,making 3D porous MXene is an important development direction for light-weight and high-efficiency electromagnetic shielding materials.As we know,the pore size of the 3D porous MXene material is related to its density and conductivity,which can affect its electromagnetic shielding ability.But now we did not know whether the gradient hole can affect the electromagnetic shielding ability of the material.On the other hand,the electromagnetic shielding performance of this material in the K-band also lacks characterization.In this paper,we had successfully prepared honeycomb structured Ti₃C₂T_x materials and Ti₃C₂T_x films with gradient pores by using PMMA spheres as template.The pore size was controlled by the PMMA microsphere.Then we studied their electromagnetic shielding performance in the K band.First we successfully prepared Ti₃C₂T_x flakes by LiF&HCl etching method and ultrasonic.By the force of Hydrogen,Ti₃C₂T_x flakes can stick on the surface of PMMA spheres after mixing them.The thickness of the outer Ti₃C₂T_x layer can be manipulated by changing the mass ratio of Ti₃C₂T_xflakes and PMMA.When using the 1.8?m diameter sphere,the best quality ratio of Ti₃C₂T_x flakes and PMMA is lower than 4:1.If the diameter of sphere is 5?m,it better lower than 2:1.Porous MXene has a low density.The existence of a large number of microporous can cause multiple reflections and scattering of electromagnetic waves,which can consume the energy of electromagnetic waves.Therefore,honeycomb structured Ti₃C₂T_x has stronger electromagnetic wave shielding ability than equal-weight Ti₃C₂T_x MXene.In the Ku band,electromagnetic shielding performance(EMI SET)of 10 wt%d-1.8?m honeycomb structured Ti₃C₂T_x can up to 34.58 dB.The SET of 10 wt%d-5?m honeycomb structured Ti₃C₂T_x can up to 32.89 dB.If we mix d-1.8?m porous Ti₃C₂T_xand d-5?m porous with the mass ratio 1:3,the max EMI SE_T could increase to 43.92 dB in Ku band.We also prepared 3D honeycomb structured Ti₃C₂T_x film by vacuum filtration successfully.We foud the conductivity of honeycomb structured Ti₃C₂T_x film is lower than MXene film with the same weight,and the larger the pore size,the more obvious the decrease.The presence of micropores enhances the electromagnetic shielding performance of the film.In the K band,the SET of the honeycomb structured Ti₃C₂T_x film is up to 62.94 dB(the SSE/t is 66475.38 dB·cm²·g^-1)only with 90.2?m thick,and the average value of SET is 60.33 dB,which is 54%higher than the equal-weight MXene film.When gradient pores were mixed to form a honeycomb structured Ti₃C₂T_x film,the increase in film thickness and the optimization of pore distribution caused by the mixing of large and small pores will further enhance the electromagnetic shielding performance of the honeycomb structured porous Ti₃C₂T_x film.If we mix d-1.8?m porous Ti₃C₂T_xand d-5?m porous with the mass ratio 1:1 to form a porous Ti₃C₂T_xfilm with 99.5?m thick,its SE_T increase to 71.41 dB(SSE/t is 75419.23 dB·cm²·g^-1)in K band,and the average value of SET is 62.33 dB,which is 60%higher than the equal-weight MXene film.This indicates that the mixing and matching of gradient pores has a beneficial effect on the electromagnetic shielding performance of honeycomb structured porous Ti₃C₂T_x film.In addition,we prepared the porous Ti₃C₂T_x&PDMS film by vacuum impregnating PDMS,which can effectively delay the oxidation of the honeycomb structured porous Ti₃C₂T_x film.This composite is expected to solve the problem of poor durability of Ti₃C₂T_x film.