Mxene Composite Preparation,Stability And Electrochemical Performance Characterization

MXene is a new type of transition metal carbonitride two-dimensional material with surface hydrophilicity,metal conductivity and good electrochemical performance.It is expected to be applied to electrode materials of supercapacitors.The electrochemical performance of multi-layer MXene is far inferior to that of few-layer MXene.And the self-stacking and easy oxidative degradation of MXene sheets will cause the electrochemical performance of MXene to decrease.This paper focuses on the preparation,stability and electrochemical performance of MXene and MXene/Fe2O3.The specific research content and conclusions are as follows.Compared the effects of the three deliminating processes of hand-shaking treatment,ultrasonic treatment and step-by-step ultrasonic treatment on the performance of the prepared MXene film.The results show that the colloidal solution prepared by the ultrasonic treatment has the highest concentration,and the film has a higher conductivity and a lower density(1006 S/cm,2.32 g/cm3).In addition,the electrochemical performance of the film is also the best,with the highest specific capacitance and the smallest voltage drop(134.5 F/g,0.015 V),and the capacitance retention rate is better.Therefore,the ultrasonic treatment was chosen as the few-layer MXene preparation process for subsequent experiments.Sodium ascorbate was added to the Ti3C2Tx colloidal solution to improve the stability of Ti3C2Tx,and compared with the pure Ti3C2Tx colloidal solution.After 15 days,two solutions were filtered through vacuum-assisted filtration to obtain films.The electrical conductivity and mass specific capacitance of the Ti3C2Tx film added with sodium ascorbate can still be maintained at 82.3%and 83.8%of the initial state.The electrical conductivity and mass specific capacitance of the pure Ti3C2Tx film decreased to 44%and 66.4%of the initial state.The results show that the addition of sodium ascorbate can improve the stability of Ti3C2Tx.By adjusting the concentration of sodium ascorbate,it is determined that adding sodium ascorbate at a concentration of 1 mg/ml has the best effect on improving the stability of Ti3C2Tx.The surface-modified Fe2O3 nanosheets were mixed with MXene(Ti3C2Tx)to prepare a self-supporting film.Fe2O3 nanosheets can provide pseudocapacitance,increase the specific surface area of the electrode,and improve the specific capacitance of the entire electrode.The specific capacitance of the composite film with a mass ratio of MXene/Fe2O3 of 3:1 is 45.6%higher than that of the pure MXene film.The specific capacitances of composite films with a mass ratio of MXene/Fe2O3 of 3:1,5:1 and 7:1 are 119.96 F/g,107.82 F/g and 103.95 F/g,respectively.In general,the greater the proportion of Fe2O3 nanosheets in the film,the greater the specific capacitance and the better the capacitance retention of the film.