Preparation And Application Of Redispersible High-concentration MXene Dough

As a new two-dimensional material with high electrical conductivity and hydrophilicity,MXene?Ti₃C₂T_x? has attracted the attention of researchers since its birth.The unique two-dimensional layered structure and terminal surface active groups endow MXene with excellent properties such as high strength,high electron mobility,high thermal conductivity and large specific surface area.Therefore,MXene has shown extraordinary potential applications in wireless communication,sensors and nanocomposite materials.However,MXene is mainly prepared by hydrofluoric acid etching,and ultimately exists as a low-concentration dispersion.As a result,MXene is extremely susceptible to oxidative deterioration and has a short storage period,and makes subsequent processing of MXene extremely difficult.The main purpose of this work is to develop a redispersible high concentration MXene,and to verify its practical application potential,thereby promoting the rapid development of MXene.The in-situ hydrofluoric acid etching method with simpler and milder reaction conditions was used to achieve the "etch-embed-peel" of the MAX phase in one step,and a high-quality and low-defect single-layered MXene nanosheet dispersion was successfully prepared.The results of Raman spectroscopy,X-ray diffraction?XRD?and X-ray photoelectron spectroscopy?XPS?show that the prepared MXene exhibits a two-dimensional layered crystal structure and contains a large amount of terminal surface-active groups?-O,-F,-OH?.In addition,the electrical conductivity test shows that the MXene has extremely excellent conductivity,and its electrical conductivity is as high as 4250 S/cm.In order to limit the excess water to fully contact the surface of the MXene nanosheet and cause oxidative deterioration,but at the same time without losing its redispersibility,this work developed a simple two-step physical concentration process,which successfully prepared a highly viscous and redispersible high concentration MXene dough.Among them,the content of MXene nanosheets in the dough is as high as 19.4 wt.% and has good processability.Meanwhile,it can be easily diluted into MXene gel or MXene dispersion.The redispersible high-concentration MXene dough can be used directly uesd as an alternative raw material for MXene.The specific capacitance of the film obtained after the MXene dough was dispersed was almost the same as that of the freshly prepared MXene film.More interestingly,the specific capacitance of the film obtained after dispersing the MXene dough for 150 d did not decline,indicating that MXene dough has excellent oxidation resistance.In addition,the film obtained after redispersion also exhibited the same electromagnetic interference shielding effect as fresh MXene.Furthermore,the MXene slurry obtained by diluting MXene dough can form a film on the surface of the epoxy resin.Based on the Joule heating effect of MXene,the MXene/epoxy resin composite film exhibits sensitive actuation.At the same time,this fluid paste can be used as a base for 3D printing.Therefore,MXene dough shows a commercial value with great development potential.