Improving environmental stability of MXene films by intercalation of N-methylformamide

Seko, Akari; Sakaida, Shun; Koyanagi, Masashi; Okada, Yasuaki; Torita, Takeshi; Anayee, Mark; Shekhirev, Mikhail; Gogotsi, Yury

doi:10.1557/s43579-023-00350-5

Cited by 6 publications

(6 citation statements)

References 30 publications

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“…[ 5 ] The robust antioxidation ability of NMF‐film originates from the strong hydrogen bonding between intercalated NMF and MXene termination groups. [ 13 ] These results show that NMF is a superior dispersant versus water and DMF for preserving Ti 3 C 2 T x MXene both in dispersion and dry films since it provides superior dispersibility and suppresses oxidation simultaneously.…”

Section: Resultsmentioning

confidence: 93%

“…[ 8,12 ] Very recently, N ‐methylformamide (NMF), has been suggested to solve the anti‐oxidation and anti‐humidity issues based on a high polarity index and H‐bonds with MXene terminations. [ 13 ] Still, the generic mechanistic understanding of processing MXenes in solvents that can provide good colloidal stability, anti‐oxidation property, and wettability is not well explored, despite its importance for potential applications.…”

Section: Introductionmentioning

confidence: 99%

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High‐permittivity Solvents Increase MXene Stability and Stacking Order Enabling Ultraefficient Terahertz Shielding

Hong,

Xu,

et al. 2023

Advanced Science

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Abstract2D transition metal carbides and nitrides (MXenes) suggest an uncommonly broad combination of important functionalities amongst 2D materials. Nevertheless, MXene suffers from facile oxidation and colloidal instability upon conventional water‐based processing, thus limiting applicability. By experiments and theory, It is suggested that for stability and dispersibility, it is critical to select uncommonly high permittivity solvents such as N‐methylformamide (NMF) and formamide (FA) (εr = 171, 109), unlike the classical solvents characterized by high dipole moment and polarity index. They also allow high MXene stacking order within thin films on carbon nanotube (CNT) substrates, showing very high Terahertz (THz) shielding effectiveness (SE) of 40–60 dB at 0.3–1.6 THz in spite of the film thinness < 2 µm. The stacking order and mesoscopic porosity turn relevant for THz‐shielding as characterized by small‐angle X‐ray scattering (SAXS). The mechanistic understanding of stability and structural order allows guidance for generic MXene applications, in particular in telecommunication, and more generally processing of 2D materials.

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Section: Resultsmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

High‐permittivity Solvents Increase MXene Stability and Stacking Order Enabling Ultraefficient Terahertz Shielding

Hong,

Xu,

et al. 2023

Advanced Science

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“…The film exhibited relatively good stability below 70 °C at the first stage. The second stage revealed 4.3% mass loss from 70 to 180 °C, attributing to the dehydration reaction of hydroxyl groups (−OH). ,− The third stage revealed 11.6% mass loss from 180 to 300 °C, which was considered to be due to the removal of chemically bound water and NMF. The fourth stage showed 7.3% mass loss from 300 to 400 °C, owing to the removal of HA and remaining chemically bound water, as HA chemically bound with TiS 2 and can only be removed at a much higher temperature than its boiling point (131.5 °C).…”

Section: Resultsmentioning

confidence: 99%

Robustly Enhanced Seebeck Coefficient in the MXene/Organics/TiS₂ Misfit Structure for Flexible Thermoelectrics

Wang

Zhang

et al. 2023

ACS Appl. Mater. Interfaces

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The flexible thermoelectric (TE) generator has emerged as a superior alternative to traditional batteries for powering wearable electronic devices, as it can efficiently convert skin heat into electricity without any safety concerns. MXene, a highly researched twodimensional material, is known for its exceptional flexibility, hydrophilicity, metallic conductivity, and processability, among other properties, making it a versatile material for a wide range of applications, including supercapacitors, electromagnetic shielding, and sensors. However, the low intrinsic Seebeck coefficient of MXene due to its metallic conducting nature poses a significant challenge to its TE application. Therefore, improving the Seebeck coefficient remains a primary concern. In this regard, a flexible MXene/organics/TiS 2 misfit film was synthesized in this work through organic intercalation, exfoliation, and re-assembly techniques. The absolute value of Seebeck coefficient of the misfit film was significantly enhanced to 44.8 μV K −1 , which is five times higher than that of the original MXene film. This enhancement is attributed primarily to the weighted effect of the Seebeck coefficient and possibly to energy-filtering effects at the heterogeneous interfaces. Additionally, the power factor of the misfit film was considerably improved to 77.2 μW m −1 K −2 , which is 18 times higher than that of the original MXene film. The maximum output power of the TE device constructed of the misfit film was 95 nW at a temperature difference of 40 K, resulting in a power density of 1.18 W m −2 , demonstrating the significant potential of this technology for driving low-energy consumption wearable electronics.

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“…Higher order peaks in the XRD spectrum correspond to the (006) and (008) planes. These peaks can be assigned to the out-of-plane 00 l reflections typical of MXene nanosheets stacked uniformly layerby-layer with respect to the surface of the substrate [44]. The difference in appearance of these peaks for both types of thick films aged under the desiccator condition is likely a result improved layer-bylayer stacking of flakes, as moisture was driven from the films (figures 4(b) and (c)).…”

Section: Effect Of Aging On Structure and Chemical Propertiesmentioning

confidence: 96%

Effect of the deposition process on the stability of Ti₃C₂T _x MXene films for bioelectronics

et al. 2023

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Ti3C2T x MXene is emerging as the enabling material in a broad range of wearable and implantable medical technologies, thanks to its outstanding electrical, electrochemical, and optoelectronic properties, and its compatibility with high-throughput solution-based processing. While the prevalence of Ti3C2T x MXene in biomedical research, and in particular bioelectronics, has steadily increased, the long-term stability and degradation of Ti3C2T x MXene films have not yet been thoroughly investigated, limiting its use for chronic applications. Here, we investigate the stability of Ti3C2T x films and electrodes under environmental conditions that are relevant to medical and bioelectronic technologies: storage in ambient atmosphere (shelf-life), submersion in saline (akin to the in vivo environment), and storage in a desiccator (low-humidity). Furthermore, to evaluate the effect of the MXene deposition method and thickness on the film stability in the different conditions, we compare thin (25 nm), and thick (1.0 µm) films and electrodes fabricated via spray-coating and blade-coating. Our findings indicate that film processing method and thickness play a significant role in determining the long-term performance of Ti3C2T x films and electrodes, with highly aligned, thick films from blade coating remarkably retaining their conductivity, electrochemical impedance, and morphological integrity even after 30 days in saline. Our extensive spectroscopic analysis reveals that the degradation of Ti3C2T x films in high-humidity environments is primarily driven by moisture intercalation, ingress, and film delamination, with evidence of only minimal to moderate oxidation.

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Improving environmental stability of MXene films by intercalation of N-methylformamide

Cited by 6 publications

References 30 publications

High‐permittivity Solvents Increase MXene Stability and Stacking Order Enabling Ultraefficient Terahertz Shielding

High‐permittivity Solvents Increase MXene Stability and Stacking Order Enabling Ultraefficient Terahertz Shielding

Robustly Enhanced Seebeck Coefficient in the MXene/Organics/TiS₂ Misfit Structure for Flexible Thermoelectrics

Effect of the deposition process on the stability of Ti₃C₂T _x MXene films for bioelectronics

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Improving environmental stability of MXene films by intercalation of N-methylformamide

Cited by 6 publications

References 30 publications

High‐permittivity Solvents Increase MXene Stability and Stacking Order Enabling Ultraefficient Terahertz Shielding

High‐permittivity Solvents Increase MXene Stability and Stacking Order Enabling Ultraefficient Terahertz Shielding

Robustly Enhanced Seebeck Coefficient in the MXene/Organics/TiS2 Misfit Structure for Flexible Thermoelectrics

Effect of the deposition process on the stability of Ti3C2T x MXene films for bioelectronics

Contact Info

Product

Resources

About

Robustly Enhanced Seebeck Coefficient in the MXene/Organics/TiS₂ Misfit Structure for Flexible Thermoelectrics

Effect of the deposition process on the stability of Ti₃C₂T _x MXene films for bioelectronics