Berlin 2015 – wissenschaftliches Programm
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SYMM: Symposium Magic MAX Phases: Self-healing, Magnetism and the Next Best Graphene
SYMM 1: Magic MAX Phases: Self-healing, Magnetism and the next best Graphene
SYMM 1.1: Hauptvortrag
Donnerstag, 19. März 2015, 09:30–10:15, H 0105
From MAX to MXene - From 3D to 2D — •Michel Barsoum — Dept. of Materials Science and Engineering, Drexel University, Philadelphia, PA, USA
By now it is well-established that the layered, hexagonal carbides and nitrides with the general formula, Mn+1AXn, (MAX) where n = 1 to 3, M is an early transition metal, A is an A-group (mostly IIIA and IVA) element and X is either C and/or N * sometimes referred to as polycrystalline nanolaminates because every basal plane is a potential deformation or delamination plane - combine some of the best attributes of metals and ceramics. In the first part of this talk, the MAX phases and their physical and mechanical properties will be reviewed.
More recently we have shown that by simply placing MAX phase powders at room temperature in HF, the A-layers are selectively etched to produce 2D materials that we labeled MXenes to emphasize the loss of the A-group element and their similarities to graphene. Unlike hydrophobic graphene, MXenes are hydrophilic that behave as *conductive clays*, a hitherto unknown combination. MXenes such as Ti2C, V2C, Nb2C and Ti3C2 can be used as electrode materials in high power lithium-ion batteries and supercapacitors. Recently volumetric capacitances of > 900 F/cm3 were obtained. The potential of using MXenes in energy storage and other applications will be highlighted.