Yi Yang,Yongbin Wang,Bin Zhou,Qi Tang,Ben Pu,Jin Cui,Yan Liu,Weiqing Yang
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.
Dayakar Gandla,Yun’an Zhou,Yihao Yan,Yifan Niu,Fuming Zhang,Daniel Q. Tan
MXenes, a class of two-dimensional transition metal carbides and nitrides, hold great promise for electrochemical energy storage applications due to their exceptional electronic conductivity, tunable surface chemistry, and pseudocapacitive charge storage mechanisms. This study introduces a one-step approach to deposit Mo and Ti-dual oxide nanoparticles in situ onto Mo2Ti2C3Tx MXene using the Lewis acid molten salt method (LAMS), meticulously optimizing annealing conditions. The incorporation of Mo and Ti dual oxide nanoparticles improves the pristine Mo2Ti2C3Tx MXene by preventing collapse of the layered structure and restacking of MXene sheets. Both three-electrode and coin cell devices are assessed in an aqueous electrolyte, illustrating the favorable role of the nanoparticles acting as spacers. Remarkable outcomes include a specific capacity of 434 C g–1 at 5 mA cm–2, exceptional capacity retention of 94% after 5000 charge–discharge cycles at 50 mA cm–2, and a high gravimetric energy density of 52.5 W h kg–1 at a power density of 1442 W kg–1 in an aqueous 3 M KOH electrolyte. This research underscores the potential of double transition metal MXenes as energy storage electrodes and an eco-friendly mass synthesis route, contributing to sustainable advancements in energy storage technology.
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