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- Anasori, Babak, et al.
(författare)
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Two-Dimensional, Ordered, Double Transition Metals Carbides (MXenes)
- 2015
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Ingår i: ACS Nano. - : AMER CHEMICAL SOC. - 1936-0851 .- 1936-086X. ; 9:10, s. 9507-9516
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Tidskriftsartikel (refereegranskat)abstract
- The higher the chemical diversity and structural complexity of two-dimensional (2D) materials, the higher the likelihood they possess unique and useful properties. Herein, density functional theory (DFT) is used to predict the existence of two new families of 2D ordered, carbides (MXenes), MM-2 C-2 and MM-2 C-2(3), where M and M are two different early transition metals. In these solids, M layers sandwich M" carbide layers. By synthesizing Mo2TiC2Tx, Mo2Ti2C3Tx, and Cr2TiC2Tx (where T is a surface termination), we validated the DFT predictions. Since the Mo and Cr atoms are on the outside, they control the 2D flakes chemical and electrochemical properties. The latter was proven by showing quite different electrochemical behavior of Mo2TiC2Tx and Ti3C2Tx. This work further expands the family of 2D materials, offering additional choices of structures, chemistries, and ultimately useful properties.
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| 2. |
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| 3. |
- Tian, Weiqian, et al.
(författare)
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Layer-by-layer self-assembly of pillared two-dimensional multilayers
- 2019
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- We report Layer-by-Layer (LbL) self-assembly of pillared two-dimensional (2D) multilayers, from water, onto a wide range of substrates. This LbL method uses a small molecule, tris(2-aminoethyl) amine (TAEA), and a colloidal dispersion of Ti3C2Tx MXene to LbL self-assemble (MXene/TAEA)(n )multilayers, where n denotes the number of bilayers. Assembly with TAEA results in highly ordered (MXene/TAEA)(n) multilayers where the TAEA expands the interlayer spacing of MXene flakes by only similar to 1 angstrom and reinforces the interconnection between them. The TAEA-pillared MXene multilayers show the highest electronic conductivity of 7.3 x10(4) S m(-1) compared with all reported MXene multilayers fabricated by LbL technique. The (MXene/ TAEA)(n) multilayers could be used as electrodes for flexible all-solid-state supercapacitors delivering a high volumetric capacitance of 583 F cm(-3) and high energy and power densities of 3.0 Wh L-1 and 4400 W L-1, respectively. This strategy enables large-scale fabrication of highly conductive pillared MXene multilayers, and potentially fabrication of other 2D heterostructures.
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| 4. |
- Tian, Weiqian, et al.
(författare)
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Multifunctional Nanocomposites with High Strength and Capacitance Using 2D MXene and 1D Nanocellulose
- 2019
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Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095.
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Tidskriftsartikel (refereegranskat)abstract
- The family of two-dimensional (2D) metal carbides and nitrides, known as MXenes, are among the most promising electrode materials for supercapacitors thanks to their high metal-like electrical conductivity and surface-functional-group-enabled pseudocapacitance. A major drawback of these materials is, however, the low mechanical strength, which prevents their applications in lightweight, flexible electronics. A strategy of assembling freestanding and mechanically robust MXene (Ti3C2Tx) nanocomposites with one-dimensional (1D) cellulose nanofibrils (CNFs) from their stable colloidal dispersions is reported. The high aspect ratio of CNF (width of approximate to 3.5 nm and length reaching tens of micrometers) and their special interactions with MXene enable nanocomposites with high mechanical strength without sacrificing electrochemical performance. CNF loading up to 20%, for example, shows a remarkably high mechanical strength of 341 MPa (an order of magnitude higher than pristine MXene films of 29 MPa) while still maintaining a high capacitance of 298 F g(-1) and a high conductivity of 295 S cm(-1). It is also demonstrated that MXene/CNF hybrid dispersions can be used as inks to print flexible micro-supercapacitors with precise dimensions. This work paves the way for fabrication of robust multifunctional MXene nanocomposites for printed and lightweight structural devices.
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