(166f) Novel Techniques for Production and Morphology Manipulation of Mxene Nanosheets

MXenes are a relatively new class of nanosheets that are derived from parent MAX ceramic phase; these nanosheets have attracted significant interest due to their unique chemical, dielectric, and transport properties, including a number of energy storage and conversion technologies. We have pioneered several new MXene research directions: (i) We have shown that Ti₃C₂ MXenes can be reversibly processed into a 3D crumpled structure. This was achieved by using capillary forces of a drying droplet in a commonly used industrial spray dryer. Without using any template, we were able to obtain scrolled, bent and folded 3D structures, and the morphology change was found to be reversible upon rehydration. (ii) One of the biggest difficulties in MXene synthesis is the common use of HF to etch away the “A” layer. We have developed an electrochemical etching approach to selectively remove Al from Ti₂AlC in diluted hydrochloride acid, forming a layer of Ti₂CTx (MXene) on Ti₂AlC. This is the first report of MXene formation where no fluoride ion is involved during etching; this is not only novel, but also desirable for safe handling and processing.