Design And Application In Supercapacitor Of Ti₃C₂-Based Composites

In the 21st century,the phenomenon of extreme poverty of traditional energy sources is becoming increasingly prominent.Green and efficient energy storage and conversion equipment has been favored by people.Among them,supercapacitors stand out due to their high energy density,long cycle life and environmental friendliness.Electrode material is a key factor that determines the performance of supercapacitors,so it is important to choose an electrode material with excellent performance.Ti3C2 is a new two-dimensional material.It has high specific surface area,high electron transfer rate and other characteristics,and has shown great potential in the field of energy storage.However,the current preparation method of Ti3C2 is easy to generate-F group on its surface。That will affect the conductivity of Ti3C2.In addition,the theoretical capacity of Ti3C2 is relatively low.These factors limit the practical application of Ti3C2.The main purpose of this experiment is to obtain the Ti3C2 matrix composites with better electrochemical performance than Ti3C2 by carrying out the loading modification of the organ-like Ti3C2.The main contents are as follows:(1)The organ-like F-Ti3C2 and NH4-Ti3C2 were prepared by HF etching and NH4HF2 etching respectively.Characterization and electrochemical performance tests show that F-Ti3C2 has better electrochemical performance.The mass specific capacitance of F-Ti3C2 is 65 F g-1 at 1 A g-1 in 1 M KOH solution.The capacitance retention rate can reach 85.1%after 3000 cycles.(2)F-Ti3C2 is used as the matrix material,and AgNO3 is used as the source of Ag.Ag/F-Ti3C2 composites with different Ag mass fractions(5 wt%,10 wt%and 20 wt%)were prepared by a simple stirring method.The test results show that the optimal loading of Ag is 10 wt%.Compared to F-Ti3C2,10Ag/F-Ti3C2 has improved its conductivity and the specific capacitance increased to 84 F g-1 at 1 A g-1.After 3000 cycles,the capacitance retention rate is 86.4%,showing excellent cycle stability.(3)F-Ti3C2 is used as the matrix material,and Fe(NO3)3·9H2O is used as the source of Fe.Fe2O3/F-Ti3C2 composites were prepared by a combination of stirring and heat treatment.XRD,SEM,TEM and other characterizations show that the Fe2O3 NPs prepared in this experiment is amorphous,distributing on the surface and interlayer of F-Ti3C2.The electrochemical test results show that the mass specific capacitance of the Fe2O3/F-Ti3C2 composite material is 252.9 F g-1 at 1 A g-1,and the capacitor retention rate is still 78.2%after 3000 cycles.