MXene titanium carbide synthesized by hexagonal titanium aluminum carbide with high specific capacitance and low impedance

The electrochemical properties of the MXene titanium carbide, Ti3C2, which has received much attention in the application of electrode materials for supercapacitors, are affected by the different morphologies of its precursor. In particular, the increase of layer spacing and specific capacitance, as well as the decrease of impedance and the dynamics analysis of Ti3C2 etched from hexagonal Ti3AlC2 precursors, are still not clear, and need to be further studied and explored. In this work, MXene Ti3C2 was synthesized efficiently in 2 hours by microwave assisted selective etching with hexagonal Ti3AlC2 as the precursor material. The specific capacitance of the Ti3C2 electrode is up to 357.85 F g-1, while the ohmic resistance RΩ of the whole electrochemical energy storage system is 0.234 ohm and the charge transfer resistance Rct is 0.875 ohm. By analyzing the structural evolution and electrochemical properties from hexagonal Ti3AlC2 to Ti3C2, it is revealed that Ti3C2 prepared with hexagonal Ti3AlC2 as the precursor material has larger atomic layer spacing, more active sites, smaller diffusion impedance and higher energy storage efficiency than that prepared with ordinary Ti3AlC2. These lay a structural foundation for improving the energy storage performance of Ti3C2 supercapacitor electrodes.