Probing the Mechanism of High Capacitance in 2D Titanium Carbide Using In Situ X‐Ray Absorption Spectroscopy

Electrochemical in situ X-ray absorption spectroscopy (XAS) of 2D titanium carbide MXene is used to probe the mechanism of high capacitance of Ti3C2Tx MXene. Changes in the Ti oxidation state are detected during cycling, confirming that most of the capacitance of Ti3C2Tx is due to changes in the Ti oxidation state, i.e., pseudocapacitance.