Chemical Intercalant Affects the Structural Properties and Aqueous Stability of V2CTx MXene

Vanadium carbide (V₂CT_x) MXene is a 2D nanomaterial widely investigated for energy storage applications due to its superior electrochemical properties. However, V₂CT_x quickly degrades in water, which limits its performance and longevity. Furthermore, the relationship between V₂CT_x MXene synthesis parameters and their corresponding aqueous stability is underexplored. In this study, delaminated V₂CT_x MXene films synthesized with four tetraalkylammonium hydroxide intercalants were characterized for their structural and aqueous stability differences. Delaminated V₂CT_x MXene d-spacing, flake edge lengths, and surface morphology were generally dependent on the intercalant radius. Specifically, the intercalant radius exhibited a positive correlation with d-spacing and a negative correlation with flake edge lengths. These structural differences have direct impacts on the aqueous stability of V₂CT_x. For example, Raman spectra of each thin film indicated that amorphous carbon formation upon water exposure positively corresponded with flake edge lengths. 3D printed film holders were fashioned to mimic electrochemical cell configurations to evaluate vanadium dissolution from each film when exposed to water. Vanadium dissolution from each film was statistically similar (i.e., no correlation with intercalant radius) and substantial (i.e., ppm concentration range). These findings will benefit aqueous applications of V₂CT_x MXenes, where material degradation and vanadium release may impact MXene performance.