Tailoring Structure,Composition, and Energy Storage Properties of MXenes from Selective Etching of In‐Plane,Chemically Ordered MAX Phases |
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| Authors: | Ingemar Persson Ahmed el Ghazaly Quanzheng Tao Joseph Halim Sankalp Kota Vanya Darakchieva Justinas Palisaitis Michel W. Barsoum Johanna Rosen Per O. Å. Persson |
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| Affiliation: | 1. Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Link?ping University, Link?ping, Sweden;2. Department of Materials Science and Engineering, Drexel University, Philadelphia, PA, USA;3. Terahertz Materials Analysis Center and Center for III‐Niitride Technology C3NiT‐Janzén, Department of Physics, Chemistry and Biology (IFM), Link?ping University, Link?ping, Sweden |
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| Abstract: | The exploration of 2D solids is one of our time's generators of materials discoveries. A recent addition to the 2D world is MXenes that possses a rich chemistry due to the large parent family of MAX phases. Recently, a new type of atomic laminated phases (coined i‐MAX) is reported, in which two different transition metal atoms are ordered in the basal planes. Herein, these i‐MAX phases are used in a new route for tailoriong the MXene structure and composition. By employing different etching protocols to the parent i‐MAX phase (Mo2/3Y1/3)2AlC, the resulting MXene can be either: i) (Mo2/3Y1/3)2C with in‐plane elemental order through selective removal of Al atoms or ii) Mo1.33C with ordered vacancies through selective removal of both Al and Y atoms. When (Mo2/3Y1/3)2C (ideal stoichiometry) is used as an electrode in a supercapacitor—with KOH electrolyte—a volumetric capacitance exceeding 1500 F cm?3 is obtained, which is 40% higher than that of its Mo1.33C counterpart. With H2SO4, the trend is reversed, with the latter exhibiting the higher capacitance (≈1200 F cm?3). This additional ability for structural tailoring will indubitably prove to be a powerful tool in property‐tailoring of 2D materials, as exemplified here for supercapacitors. |
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| Keywords: | 2D materials capacitance in‐plane order MXene vacancies |
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