Abstract: MXenes have promises in myriad applications by virtue of two-dimensional nature and adjustable functional groups. To achieve the applications, MXenes are always first prepared in the form of aqueous suspension. However, fast degradation caused by the attack of dissolved oxygen and water molecules is the main obstacle to the application of MXenes. It has come to light that the degradation preferentially takes place at defective sites and edges where defects enrich. To tackle this problem and increase the stability, herein, using Ti₃C₂T_x MXene as a model material, we report a simple yet efficient strategy for long term storage of MXene suspension by introducing glycerol, a typical polyhydric alcohol. The effectiveness of the strategy is evidenced by structural compositional and morphological investigations. Glycerol protects the defective sites of MXene flakes through restricting water and/or oxygen molecules from reactive sites. This is supported by ab initio molecular dynamics simulations that form hydrogen bonds between MXene and glycerol molecules just over defective sites. Following this mechanism, other polyhydric alcohols, such as ethylene glycol and propylene glycol, are also effective in stabilizing Ti₃C₂T_x MXene suspension. The strategy based on polyhydric alcohols has the potential to be extended to other MXenes, solving the most urgent challenge in the field of MXene engineering.

Key words: MXene, Stability, Polyhydric alcohols, Glycerol, Ethylene glycol and propylene glycol