High capacitance of surface-modified 2D titanium carbide in acidic electrolyte

The electrochemical behavior of Ti3C2, a two-dimensional titanium carbide from the MXene family, in H2SO4 electrolyte is reported. To demonstrate the effect of surface chemistry on capacitive performance, Ti3C2 was modified by delamination or intercalation treatments. Electrochemical testing revealed an increase in capacitance, which was attributed to oxygen-containing functional groups. An extraordinary high intercalation capacitance of 415 F·cm− 3 at 5 A·g− 1 was obtained from electrodes with a specific surface area of just 98 m2·g− 1. Values up to 520 F·cm− 3 were recorded for delaminated MXene films at 2 mV·s− 1. This study highlights that the behavior of materials from the large family of two-dimensional MXene can be tuned by suitable modification of their surface chemistry.