Preparation And Application Of Twodimensional Transition Metal Carbide?Ti₃C₂T_x? Composites

MXenes are a new family of two-dimensional early transition metal carbides or carbonitrides.Its general formula is M_n+1X_nT_x,where M is a transition metal,X is C and/or N,T_x represents surface functional groups,and n=1 to 3.Ti₃C₂T_x?MXene?,as a member of MXenes material,has exhibited great potential in energy storage system,gas adsorption,sensors,conductive fillers and other fields because of large surface area and excellent conductivity,and become a new research hotspot after Graphene.However,the low capacitance of Ti₃C₂T_x material and its multi-layer stacking structure have limited its practical applications.Therefore,the improvement of electrochemical performance of Ti₃C₂T_x material still need for more in-depth study.Due to the synergistic effect between different components,combining two or more materials becomes an effective way to improve the performance of Ti₃C₂T_x material.In this paper,delaminated MXene was prepared by ultrasonic treatment Ti₃C₂T_x powders with dimethyl sulfoxide?DMSO?followed by magnetic stirring in KOH aqueous solution.Then,we prepared MXene/MnO₂ and MXene/PANI composites,MXene/CNTs/MnO₂and MXene/PANI/CNTs ternary composites on the basis of delaminated MXene.Finally,we study the microstructure and electrochemical properties of the as-prepared composites.The main woks include as the following aspects:?1?MXene/MnO₂ composite was prepared by deposition of manganese dioxide particles on the surface of MXene sheet by hydrothermal method.The specific capacitance,rate performance and cycle stability of MXene/MnO₂ composite were studied.The results show that the addition of manganese dioxide solves the problem of low capacitance of MXene material,but does not significantly improve the rate performance and cycle stability.?2?The MXene/CNTs framework material was prepared by freeze-drying method and ternary composite of MXene/CNTs/MnO₂ was by hydrothermal method.The electrochemical performances of the MXene/CNTs/MnO₂ composite material were studied.The combination of MXene material with manganese dioxide and carbon nanotubes not only improves the specific capacitance of the material,but also improves the rate performance and cycle stability of MXene material.?3?MXene/PANI composite were prepared by in-situ polymerization of aniline monomer on the surface of MXene sheets under acidic conditions,and the electrochemical properties of the as-prepared composite were studied by electrochemical measurements.After a series of electrochemical tests,MXene/PANI composite has high specific capacitance and excellent rate performance and cycle stability.?4?The MXene/CNTs framework material was prepared by freeze-drying method and ternary composite of MXene/CNTs/MnO₂ was by hydrothermal method and MXene/CNTs/PANI composite were prepared by in-situ polymerization of aniline monomer under acidic conditions.Finally,the electrochemical properties of the composite were studied by electrochemical measurements.The addition of carbon nanotubes further improves the rate performance and cycle stability of MXene material.