Ultralong Stability of Ti3C2Tx‐MXene Dispersion Through Synergistic Regulation of Storage Environment and Defect Capping with Tris‐HCl Buffering

Abstract

AbstractAqueous MXene dispersion suffers from a bottleneck issue of oxidation, leading to its gradual deterioration and ultimately compromised physicochemical characteristics. Herein, Tris‐HCl buffer is employed to stabilize the diluted Ti3C2Tx‐MXene dispersion (0.05 mg mL−1) through the synergy of its potent pH‐regulation capability and capping effect toward oxidation‐susceptible defects/edges. Tris‐HCl functionalized Ti3C2Tx maintained its original morphology, structure, and favorable dispersity even after 150 days of aging under naturally aerated conditions. The pH‐regulation nature of Tris‐HCl is elucidated through solution monitoring of Ti3C2Tx dispersion, while the adsorption of Tris‐HCl onto defects/edges is revealed by spectral analysis and multi‐scale simulations. Tris‐HCl at the neutral pH can bind to the negatively charged basal plane of Ti3C2Tx via +HTris moiety, while the other moiety (Tris) interacts with the exposed edge‐based Ti atoms and/or intrinsic defects, forming a Ti─N bond that prevents MXene from attack by H2O and O2. Besides, Tris‐HCl stabilized Ti3C2Tx exhibited nearly identical capacitive characteristics to its freshly‐etched counterpart, indicating the minimal impact of Tris‐HCl on electrochemical performance of Ti3C2Tx during long‐term storage. This study provides practical guidance for stabilizing MXene in their native aqueous dispersion without compromising the inherent properties.