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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.