Methods for the Production and Scale-up of Novel MXene Materials

MXenes are a remarkable class of 2-D nanosheets that hold promise for use in numerous defense applications including electromagnetic shielding and energy storage. MXenes are produced by selective etching of A element layers from a parent MAX phases - a family of carbides and nitrides with a layered nanostructure and a general formula of Mn+1AXn, consisting of an early transition metal (M), main-group sp-elements (A is predominantly from IIIA or IVA groups), and a carbon and/or nitrogen (X). Despite a number of high-profile reports on MXene properties, major research challenges remain in their processing, particularly in regard to (i) novel MXene compositions beyond Titanium-based structures and (ii) scaleup of production beyond the labscale. In the proposed work, we aim to develop novel MAX phases with new compositions and with guest molecules that will allow for easier and less hazardous etching of the A-phase to yield previously unobtainable MXenes. We will also establish new methodologies (including reactor setup) for scaling up the etching step; this will avoid both over-etching of the M-phase and safety concerns associated with strong acids. These Phase I efforts will demonstrate both new MXene types and the ability to make these structures at DOD-relevant scales.