The size effect of Ti ₃ C ₂ T _x nanosheet on the charge storage capability

This study explores the influence of lateral dimensions on the electrochemical performance of Ti 3 C 2 T x . Both Ti 3 C 2 T x with big lateral (Ti 3 C 2 T x -B) and Ti 3 C 2 T x with medium lateral (Ti 3 C 2 T x -M) exhibit a surface-controlled charge storage mechanism across all scan rates, with Ti 3 C 2 T x -M showing a significant contribution from surface capacitance. In contrast, only the small lateral Ti 3 C 2 T x (Ti 3 C 2 T x -S) displayed a diffusion-controlled process, and, within the same electrochemical potential range, it demonstrated significant hydrogen evolution performance. Ti 3 C 2 T x -M achieves the highest specific capacitance of 412 F g −1 at 0.5 A g −1 , surpassing Ti 3 C 2 T x -B, which reaches 350 F g −1 . These findings indicate that the lateral size restrict ion diffusion in the electrolyte, impacting the reaction rate, as smaller dimensions allow ions more time to traverse pores while their diffusion is influenced by the availability of active sites on the electrode surface.