Study On Mechanical Properties Of Ti₃C₂ Defective Two-dimensional Material

In recent years,two-dimensional solid materials have gradually become a hot research field,because of its unique properties and great potential in all fields.At present,MXene has been synthesized as follows:Ti₂C,Ti₃C₂,Ta₄C₃,(Ti_0.5,Nb_0.5)₂C,(V_0.5,Cr_0.5)₃C₂,Ti₃CN_X（x<1）,Nb₂C and V₂C.Since the discovery of MXenes,there has been increasing interest in its structure,properties,and potential applications.Previous studies have shown that the conductivity of independent cold-pressed MXene disks is comparable to that of multilayered graphene.At the same time,it is found that some MXenes（2D Ti₃C₂,Ti₂C,Nb₂C and V₂C）have excellent lithium ion storage performance and are very promising cathode materials for lithium ion batteries.Which Ti₃C₂ is an excellent potential MXene material,since it has more than 10000S/cm high electrical conductivity,about 4 g/cm3 high packing density and 1500 F/cm3 turns capacitance characteristic,in the field of new energy storage materials and new type of semiconductor electronic components has wide application,but at present domestic and foreign research on Ti₃C₂ is mostly about its use in the field of physics and chemistry,for the study of the structure of the defective is less,and numerous studies of two-dimensional material are shown in this area have fully tap the value of,Therefore,it is practical and necessary for us to study the performance of Ti₃C₂ and its structure with defects.Because of the particularity of two-dimensional materials,we adopt the first principle based on density functional theory to study.We studied the Ti₃C₂T_X（T-O,F,-OH and other functional groups）on the mechanical and electronic properties,analyzed their respective band structure and density of states,and to calculate the elastic modulus,poisson’s ratio and young’s modulus and stress strain curve,studies the different functional groups on the Ti3C2two-dimensional material mechanics,the influence of the electronic performance;Then build the supercell Ti₃C₂and replace the doping sites atoms are needed to establish and research contains V,B,N doping Ti₃C₂ structure,found that in addition to V in the surface of Ti locus formed by doping structure,all the doping makes Ti₃C₂ structure of critical strain and the yield limit is reduced,suggesting that its ability to resist tensile deformation is weak;In addition,it is found that the young’s modulus and Poisson’s ratio of each doping structure become smaller,and each doping structure also has a lower elastic constant in addition to B doping.Each doping structure still has good conductivity,and the influence of the doping of N atoms on the electronic performance of the structure is mainly reflected in the slight increase of the quantum state near the valence band top（VBM）,which has little influence on the Fermi energy level and conduction band.However,the doping of both Types of V atoms has a weak influence on the overall electronic performance of the structure.V atoms can well replace the electronic performance of Ti atoms at the doping site,and the contribution of V doping to Fermi energy level is higher than that of V doping at the interlayer Ti site.The doping of B mainly affects the 3D orbital electrons of Ti atom,so that the number of quantum states near Fermi energy level and conductance band bottom（CBM）of Ti atom are greatly increased,and the conductance band performance of the structure is greatly improved.This has important implications for the application of Ti₃C₂ in energy storage and nanoscale structures.