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

摘要

The electrochemical behavior of Ti_3C_2, a two-dimensional titanium carbide from the MXene family, in H_2SO_4 electrolyte is reported. To demonstrate the effect of surface chemistry on capacitive performance, Ti_3C_2 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 m~2·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.