Synthesis and Characterization of 2D Molybdenum Carbide (MXene). (17th February 2016) - Halim, Joseph
Abstract : Large scale synthesis and delamination of 2D Mo2 CT x (where T is a surface termination group) has been achieved by selectively etching gallium from the recently discovered nanolaminated, ternary transition metal carbide Mo2 Ga2 C. Different synthesis and delamination routes result in different flake morphologies. The resistivity of free‐standing Mo2 CT x films increases by an order of magnitude as the temperature is reduced from 300 to 10 K, suggesting semiconductor‐like behavior of this MXene, in contrast to Ti3 C2 T x which exhibits metallic behavior. At 10 K, the magnetoresistance is positive. Additionally, changes in electronic transport are observed upon annealing of the films. When 2 μm thick films are tested as electrodes in supercapacitors, capacitances as high as 700 F cm −3 in a 1m sulfuric acid electrolyte and high capacity retention for at least 10, 000 cycles at 10 A g −1 are obtained. Free‐standing Mo2 CT x films, with ≈8 wt% carbon nanotubes, perform well when tested as an electrode material for Li‐ions, especially at high rates. At 20 and 131 C cycling rates, stable reversible capacities of 250 and 76 mAh g −1, respectively, are achieved for over 1000 cycles. Abstract : 2D Mo2 C (MXene) is produced using different synthesis routes, which lead to different flake morphologies. Mo2 C exhibits a semiconductor‐like increase in resistivity from 300 to 10 K. Mo2 C electrodes in a supercapacitor achieve 700 F cm −3 capacitance in 1m H2 SO4 for 10, 000 cycles. Mo2 C–Carbon nano tube (CNT) electrodes possess 250 mAh g −1 capacity for 1000 cycles, showing promise as anode for batteries and Li‐ion capacitors.