Study On Preparation And Supercapacitive Properties Of MXene-based Composites

As a new two-dimensional material,MXene is an ideal supercapacitor electrode material and has received wide attention from scholars because of its good hydrophilicity and conductivity.However,MXene's self-stacking reduces the surface utilization of the material and influence the performance of supercapacitor.This study was aimed to improve self-stacking of MXene,by changing the preparation of films and adding to pseudocapacitor material Mn O₂nanowires to increase the contacted area of the film with the electrolyte and the ion diffusion in the film and improve the specific capacitance of the material.The detailed study includes:two-dimensional Ti₃C₂T_xobtained by mixing Li F and HCl to etch Ti₃Al C₂is used as a base material,and the vacuum evaporation-induced self-assembly film reduces the degree of stacking of the film which has a higher conductivity and a lower density?1.4 x 10⁵S/m and1.5 g/cm³?than the vacuum-filtered film.The specific capacitance of the evaporation self-assembly film is as high as 168.5 F/g,which is 2.15 times that of the filter membrane and has excellent rate performance and stability.1mol/L H₂SO₄electrolyte can show the best capacitance performance.Different thickness film was prepared by vacuum evaporation-induced self-assmbly process.When the film thickness was 5?m,the evaporation self-assembled film showed188.93 F/g at 10 m V/s,which had good stability.With the increase of thickness,the specific capacitance decreased.When the thickness reaches a certain thickness,the capacitance will be steady.When the thickness is 45?m,the specific capacitance is 91.6 F/g at 5 m V/s,and also has good mechanical properties.The surface electrical properties of the Mn O₂nanowires were changed and directly mixed with the Ti₃C₂T_xcolloid,and then vacuum-filtered with Ti₃C₂T_x?MXene?to obtain a self-supporting composite film.The pseudocapacitor material is added to the film as an intermediate layer to increase layer spacing of the film and the specific capacitance of the film.Increased Mn O₂content increases specific capacitance,when the amount of Mn O₂reaches16.6%?wt?,the specific capacitance increases to 116 F/g which if 70%higher compared to pure Ti₃C₂T_xfilm,and it also has good conductivity and rate performance.