Rational fabrication of flower-like VS2-decorated Ti3C2 MXene heterojunction nanocomposites for supercapacitance performances

In this work, Ti3C2, was obtained by selective etching of Al in Ti3AlC2 by hydrofluoric and VS2 was modified on two-dimensional Ti3C2 by solvothermal process to prepare VS2/Ti3C2 composites. In the three-electrode system, the prepared VS2/Ti3C2 composites were compared with VS2 and Ti3C2, respectively, and it was found that the electrochemical properties of VS2/Ti3C2 composites were better. The intercalated VS2 nanosheets expanded the distance between Ti3C2 sheets, leading to a wide ion-accessible surface region and fast ionic/electric transport, resulting in the improved the electrochemical performance of the Ti3C2/VS2 composites. Density functional theory (DFT) analysis shows that the prepared VS2/Ti3C2 composite material has high electrical conductivity. Under the current density of 1 A.g(-1), the specific capacity of VS2/Ti3C2 composite is 191.3 mAh.g(-1), which is much higher than that of VS2 and Ti3C2. The asymmetric supercapacitors were assembled with VS2/Ti3C2 composites as positive electrodes, and the electrochemical performance was tested when the power density was 1288 W.kg(-1) and the energy density was 24 Wh.kg(-1). The initial capacity retention is 82.2% after 5000 cycles of constant current charge and discharge at the current density of 2 A.g(-1). In short, VS2/Ti3C2 composites show excellent supercapacitor performance in terms of capacity, stability, energy density and power density. It shows that VS2/Ti3C2 is a promising electrode material for supercapacitors.

Automated summary

The modification of two-dimensional Ti3C2 with VS2 to prepare VS2/Ti3C2 composites significantly improves the electrochemical performance of supercapacitors, enhancing specific capacity and cycling stability.