Understanding Chemistry of Two-Dimensional Transition Metal Carbides and Carbonitrides (MXenes) with Gas Analysis

Huang, Shuohan; Mochalin, Vadym

doi:10.1021/acsnano.0c03602

Cited by 98 publications

(97 citation statements)

References 31 publications

(54 reference statements)

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“…While both MAX phases have comparable Ti L‐edge profiles, it can be clearly observed that the Ti L‐edge energy of Ti 2 C 0.5 N 0.5 T x MXene moves slightly to a higher energy side compared with that of Ti 2 CT x MXene, indicating a higher average for Ti oxidation state in Ti 2 C 0.5 N 0.5 T x MXene than that of Ti 2 CT x MXene. This is consistent with the reported theoretical results showing a lower stability of carbonitrides relative to their carbide counterparts 42,43 . In addition, the bonding of TiO 2− x F x and CNTiF x are located at higher binding energy regions because of the highly electronegative from F atom 61 .…”

Section: Resultssupporting

confidence: 92%

“…To date, over 40 different MXene compositions have been reported; the vast majority of these MXenes are carbides with only a few exceptions—several nitrides and only one carbonitride ( viz ., Ti 3 CNT x ) 27 . The latter has shown distinct properties and behavior compared with Ti 3 C 2 T x in many applications including energy storage, 28–33 optics, 34,35 catalysis, 36–39 electromagnetic shielding, 40,41 sensing, 42,43 and so forth. This distinct behavior of Ti 3 CNT x compared with Ti 3 C 2 T x provides a strong motivation to develop other new carbonitrides to join the MXene family.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of new two‐dimensional titanium carbonitride Ti₂C₀_.₅N₀_.5T_xMXene and its performance as an electrode material for sodium‐ion battery

Liang

Tabassum

Majed

et al. 2021

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Two‐dimensional (2D) layered transition metal carbides/nitrides, called MXenes, are attractive alternative electrode materials for electrochemical energy storage. Owing to their metallic electrical conductivity and low ion diffusion barrier, MXenes are promising anode materials for sodium‐ion batteries (SIBs). Herein, we report on a new 2D carbonitride MXene, viz., Ti2C0.5N0.5Tx (Tx stands for surface terminations), and the only second carbonitride after Ti3CNTx so far. A new type of in situ HF (HCl/KF) etching condition was employed to synthesize multilayer Ti2C0.5N0.5Tx powders from Ti2AlC0.5N0.5. Spontaneous intercalation of tetramethylammonium followed by sonication in water allowed for large‐scale delamination of this new titanium carbonitride into 2D sheets. Multilayer Ti2C0.5N0.5Tx powders showed higher specific capacities and larger electroactive surface area than those of Ti2CTx powders. Multilayer Ti2C0.5N0.5Tx powders show a specific capacity of 182 mAh g−1 at 20 mA g−1, the highest among all reported MXene electrodes as SIBs with excellent cycling stability.

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Section: Resultssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Synthesis of new two‐dimensional titanium carbonitride Ti₂C₀_.₅N₀_.5T_xMXene and its performance as an electrode material for sodium‐ion battery

Liang

Tabassum

Majed

et al. 2021

InfoMat

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“…[69] The results of these weak X-X interactions in the MXenes' structure have been observed experimentally in the preferential evolution of methane gas during MXenes' hydrolysis. [73] The metallic bonding between the transition metals occurs via d-orbitals, which are not shared with carbon or nitrogen. [68] However, this metallic bonding between M-M contributes less to the lattice bond energy than M-X bonds.…”

Section: Mechanical Behavior Of Mxenesmentioning

confidence: 99%

2D MXenes: Tunable Mechanical and Tribological Properties

2021

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carbon/nitrogen (X) with bonded terminations (T x : -O 2 , -F 2 , -(OH) 2 , -Cl 2 , or their combinations) on the exterior transition metal surfaces. [6][7][8] MXenes' crystal structures and chemical formula are derived from their 3D crystalline precursors, which are usually MAX phases. [9] MAX phases are chemically denoted by M n+1 AX n (n = 1 to 4), for which the M-X layers found in MXenes are sandwiched by layers of A-group elements (mostly group 13-16 of the periodic table). [10] MXenes are synthesized by selectively removing/ etching these A-group element layers. Upon the removal of these A layers, surface terminations (T x ) occupy the bonding sites on M layers previously bonded to the A-group elements. [11] MXenes are excellent candidates for a range of applications (Figure 1a), including energy storage, [7] transparent electronics, [12,13] sensors, [14] electromagnetic interference (EMI) shielding, [15,16] and catalysis. [17] These applications involve MXenes as flexible and thin films, [13] MXenes as anchors in hybrid materials, [18] embedded in matrix materials, [19,20] or even as wearable fabrics. [21] In almost all these applications, fundamental understanding of the mechanical and tribological properties of MXenes is necessary (Figure 1b). The mechanical properties are vital to MXenes' applications in energy storage and catalysis, as MXenes in electrodes can act as active materials, conductive additives, strong binders, and current collectors, which can control the structure of the electrode and withstand expansion and contraction during charge and discharge cycles. [7,22] Additionally, the rise of flexible and wearable devices [13,21,23] necessitates mechanical characterization of MXene to withstand the required mechanical forces while maintaining the flexibility for these applications. Similarly, the potential applications of MXenes in triboelectric nanogenerators for energy storage and wearable electronics requires the characterization of MXenes' tribological properties. [24] More recently, MXenes have been used as reinforcement phases in composite materials. [25] The relevance of the mechanical and tribological properties in various applications is illustrated in Figure 1b. The rationale and support for this figure is summarized in Figures S1 and S2, Supporting Information, and discussed further in the Supporting Information.Despite well over 3000 publications to date on MXenes since their discovery, [26] only 4.9% of publications have studied their mechanical and tribological properties and their applications as reinforcement materials in composites, as shown in Figure 1a. Only two experimental studies on the mechanical stiffness 2D transition metal carbides, nitrides, and carbonitrides, known as MXenes, were discovered in 2011 and have grown to prominence in energy storage, catalysis, electromagnetic interference shielding, wireless communications, electronic, sensors, and environmental and biomedical applications. In addition to their high electrical conductivity and electrochemically activ...

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“…However, the non-proportional relationship between the decreased pH value and increased atomic percentage of Ti(IV) does not prove this hypothesis [42]. Huang and co-worker later claimed that only CH 4 is released during degradation of carbide MXenes, whereas carbonitride MXene (Ti 3 CNT x ) released NH 3 as well [53]. After considering the oxidation mechanism, we summarize possible ways to minimize or delay the oxidation degradation of MXenes under different controlled conditions.…”

Section: Oxidative Degradation Of Mxenes and Influencing Parametersmentioning

confidence: 99%

Improving oxidation stability of 2D MXenes: synthesis, storage media, and conditions

et al. 2021

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Understanding and preventing oxidative degradation of MXene suspensions is essential for fostering fundamental academic studies and facilitating widespread industrial applications. Owing to their outstanding electrical, electrochemical, optoelectronic, and mechanical properties, MXenes, an emerging class of two-dimensional (2D) nanomaterials, show promising state-of-the-art performances in various applications including electromagnetic interference (EMI) shielding, terahertz shielding, electrochemical energy storage, triboelectric nanogenerators, thermal heaters, light-emitting diodes (LEDs), optoelectronics, and sensors. However, MXene synthesis using harsh chemical etching causes many defects or vacancies on the surface of the synthesized MXene flakes. Defective sites are vulnerable to oxidative degradation reactions with water and/or oxygen, which deteriorate the intrinsic properties of MXenes. In this review, we demonstrate the nature of oxidative degradation of MXenes and highlight the recent advancements in controlling the oxidation kinetics of MXenes with several promising strategic approaches, including careful control of the quality of the parent MAX phase, chemical etching conditions, defect passivation, dispersion medium, storage conditions, and polymer composites.

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Understanding Chemistry of Two-Dimensional Transition Metal Carbides and Carbonitrides (MXenes) with Gas Analysis

Cited by 98 publications

References 31 publications

Synthesis of new two‐dimensional titanium carbonitride Ti₂C₀_.₅N₀_.5T_xMXene and its performance as an electrode material for sodium‐ion battery

Synthesis of new two‐dimensional titanium carbonitride Ti₂C₀_.₅N₀_.5T_xMXene and its performance as an electrode material for sodium‐ion battery

2D MXenes: Tunable Mechanical and Tribological Properties

Improving oxidation stability of 2D MXenes: synthesis, storage media, and conditions

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Understanding Chemistry of Two-Dimensional Transition Metal Carbides and Carbonitrides (MXenes) with Gas Analysis

Cited by 98 publications

References 31 publications

Synthesis of new two‐dimensional titanium carbonitride Ti2C0.5N0.5TxMXene and its performance as an electrode material for sodium‐ion battery

Synthesis of new two‐dimensional titanium carbonitride Ti2C0.5N0.5TxMXene and its performance as an electrode material for sodium‐ion battery

2D MXenes: Tunable Mechanical and Tribological Properties

Improving oxidation stability of 2D MXenes: synthesis, storage media, and conditions

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Synthesis of new two‐dimensional titanium carbonitride Ti₂C₀_.₅N₀_.5T_xMXene and its performance as an electrode material for sodium‐ion battery

Synthesis of new two‐dimensional titanium carbonitride Ti₂C₀_.₅N₀_.5T_xMXene and its performance as an electrode material for sodium‐ion battery