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Scaling the production of synthetic 2D materials to industrial quantities has faced significant challenges due to synthesis bottlenecks whereby few have been produced in large volumes. These challenges typically stem from bottom‐up approaches limiting the production to the substrate size or precursor availability for chemical synthesis and/or exfoliation. In contrast, MXenes, a large class of 2D transition metal carbides and/or nitrides, are produced via a top‐down synthesis approach. The selective wet etching process does not have similar synthesis constraints as some other 2D materials. The reaction occurs in the whole volume; therefore, the process can be readily scaled with reactor volume. Herein, the synthesis of 2D titanium carbide MXene (Ti3C2Tx) is studied in two batch sizes, 1 and 50 g, to determine if large‐volume synthesis affects the resultant structure or composition of MXene flakes. Characterization of the morphology and properties of the produced MXene using scanning electron microscopy, X‐ray diffraction, dynamic light scattering, Raman spectroscopy, X‐ray photoelectron spectroscopy, UV–visible spectroscopy, and conductivity measurements show that the materials produced in both batch sizes are essentially identical. This illustrates that MXenes experience no change in structure or properties when scaling synthesis, making them viable for further scale‐up and commercialization. [ABSTRACT FROM AUTHOR]

Flexible antennas have the potential to transform wearable and fabric-based wireless sensing technologies. The antenna discussed in this study is part of a sensing system that uses the back-scattered power level as the decision metric. For a good wireless sensor, it is necessary to offer a feasible read range and maintain good distinctions in the back-scattered power levels between the different states (i.e. level of stretch) of the antenna. Moreover, effects due to human body proximity should be minimised. For these reasons, the radiation efficiency is a crucial parameter to investigate. This study presents the radiation efficiency measurement of the proposed flexible knitted 'Bellyband' antenna at two different levels of stretch in a reverberation chamber. This work validates the reverberation chamber measurements through comparison with simulations and anechoic chamber measurements at 900 MHz. Moreover, this work demonstrates how the approach can be used to quantify bellyband antenna efficiency in the vicinity of a human body. Finally, the efficiency results were used to predict the read range of Bellyband radio frequency identification technology. [ABSTRACT FROM AUTHOR]

Abstract: Until now, MXenes could only be produced from MAX phases containing aluminum, such as Ti3AlC2. Here, we report on the synthesis of Ti3C2 (MXene) through selective etching of silicon from titanium silicon carbide—the most common MAX phase. Liters of colloidal solutions of delaminated Ti3SiC2‐derived MXene (0.5–1.3 mg mL−1) were produced and processed into flexible and electrically conductive films, which show higher oxidation resistance than MXene synthesized from Ti3AlC2. This new synthesis method greatly widens the range of precursors for MXene synthesis. [ABSTRACT FROM AUTHOR]

Free-standing films that display high strength and high electrical conductivity are critical for flexible electronics, such as electromagnetic interference (EMI) shielding coatings and current collectors for batteries and supercapacitors. 2D Ti 3 C 2 T x flakes are ideal candidates for making conductive films due to their high strength and metallic conductivity. It is, however, challenging to transfer those outstanding properties of single MXene flakes to macroscale films as a result of the small flake size and relatively poor flake alignment that occurs during solution-based processing. Here, a scalable method is shown for the fabrication of strong and highly conducting pure MXene films containing highly aligned large MXene flakes. These films demonstrate record tensile strength up to ≈570 MPa for a 940 nm thick film and electrical conductivity of ≈15 100 S cm -1 for a 214 nm thick film, which are both the highest values compared to previously reported pure Ti 3 C 2 T x films. These films also exhibit outstanding EMI shielding performance (≈50 dB for a 940 nm thick film) that exceeds other synthetic materials with comparable thickness. MXene films with aligned flakes provide an effective route for producing large-area, high-strength, and high-electrical-conductivity MXene-based films for future electronic applications., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Until now, MXenes could only be produced from MAX phases containing aluminum, such as Ti 3 AlC 2 . Here, we report on the synthesis of Ti 3 C 2 (MXene) through selective etching of silicon from titanium silicon carbide-the most common MAX phase. Liters of colloidal solutions of delaminated Ti 3 SiC 2 -derived MXene (0.5-1.3 mg mL -1 ) were produced and processed into flexible and electrically conductive films, which show higher oxidation resistance than MXene synthesized from Ti 3 AlC 2 . This new synthesis method greatly widens the range of precursors for MXene synthesis., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)