A facile and almost HF-free synthesis of Ti3C2@CuCl composite for supercapacitors

This work demonstrates a distinctive almost HF-free route of etching Ti3AlC2 MAX phase by metal displacement reaction at room temperature. The Ti3AlC2 particles are directly etched by CuCl2 solutions in different concentrations instead of HF. The etchant is reduced to nano CuCl particles, adhering to the surface of Ti3C2 layers to form the Ti3C2@CuCl composite which is evaluated as working electrodes for supercapacitors. Due to the synergistic effect between CuCl and Ti3C2 matrix, the appropriate amount of CuCl enhances the specific capacitance to 508.7 F.g(-1) at 1A.g(-1) in 6 M KOH electrolyte solution, which is much higher than pure Ti3C2 electrode. This work shows the possibility of synthesis of various Mxene-based frameworks by other metallic cations with lower metal activity.