Fast synthesis of Mo2Ti2C3Tx by supercritical-assisted etching method for Li-ion batteries

Mo 2 Ti 2 C 3 T x , a double transition metals (DTM) MXene, has emerged as a novel promising material for a wide range of applications due to its distinctive physicochemical properties. However, the commonly used method for preparing Mo 2 Ti 2 C 3 T x directly employing hydrofluoric (HF) acid as an etchant, is not only hazardous but also time-consuming. Recognizing the exceptional solubility and ultra-fast mass transfer kinetics of supercritical CO 2 (SC-CO 2 ), we introduced an extremely rapid SC-CO 2 assisted etching method that dramatically reduced the etching duration by a factor of 64, from 96 h to 1.5 h, thereby successfully preparing Mo 2 Ti 2 C 3 T x . When served as an anode in lithium-ion batteries (LIBs), the Mo 2 Ti 2 C 3 T x electrode achieves a high reversible specific capacity of 380 mAh g −1 at a current density of 0.1 A g −1 , significantly outperforming pure DTM-MXene-based anodes in terms of most reported capacities. This work provided a promising and efficient method for the etching of DTM-MXene.