Interrogating the impact of onion-like carbons on the supercapacitive properties of MXene (Ti2CTX).

The effect of carbon onions or onionlike carbons (OLCs) as a dopant on the supercapacitive properties of titanium carbide MXene (Ti₂C) has been studied. The materials were characterized using x-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, and electrochemical techniques, including cyclic voltammetry, constant current charge/discharge, and electrochemical impedance spectroscopy. It was found that the introduction of OLCs into the layered MXene structure increases the long-term cycling stability of the material from ∼80% to >95%. It was also found to increase the supercapacitance of MXene in the 5% quantity from ca. 104 to 148 F/g but decreased the supercapacitance in the 10% quantity from ca. 104 to 92 F/g. The power and energy density improved in the 5% OLC-doped sample compared to the pristine sample for current densities between 0.5 and 5 A/g. Overall, this study showcased the unique ability of OLCs to improve the electrochemical performance of a Ti₂C-based supercapacitor. [ABSTRACT FROM AUTHOR]