Fig. 1. Experimental configuration used to isolate monolayer MXene pseudocapacitive responses.

a Schematic of the SECCM configuration for measuring monolayer Ti₃C₂T_x flakes immobilized on a carbon supporting electrode surface. SECCM-based cyclic voltammogram measurements were conducted in a hopping mode, with the probe movement pattern shown in coloured arrows (blue approach, red retract, black move to next measurement position). b Schematic of end of SECCM probe, highlighting the nanoscale electrochemical droplet cell at the end of the SECCM probe and the two-electrode electrochemical cell configuration. c Electron micrograph of sample surface containing monolayer MXene immobilized on a carbon surface after SECCM measurements, with each SECCM sample location highlighted according to the surface composition.