Battery, gas sensing material and preparation method therefor, sensor and electric device

Abstract

Disclosed in the present application are a battery, a gas sensing material and a preparation method therefor, a sensor and an electric device. The battery comprises a gas sensor, which comprises a gas sensing material, wherein the gas sensing material comprises an M / MXene composite material, the M / MXene composite material comprising a metal (M) monoatom and an MXene material, and / or comprising a metal (M) cluster and an MXene material. The gas sensing material provided by the present application can achieve the detection of a target gas in an oxygen-free or low-oxygen environment and the detection of gas production within a battery. Furthermore, the sensitivity and selectivity of gas detection can be improved, the response and recovery speeds can be increased, and the detection limit of a gas can be reduced.

Description

Battery, gas sensing material and preparation method thereof, sensor and electrical equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202311644359.8, filed on November 30, 2023, entitled “Gas Sensing Materials, Preparation Methods Thereof, Sensors, Batteries and Electrical Equipment,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of new energy technology, and in particular to batteries, gas sensing materials and preparation methods thereof, sensors and electrical equipment. Background Art

[0004] As global energy and environmental problems continue to intensify, new energy, as one of the areas of sustainable development, is developing rapidly. Batteries are being used more and more widely as a new energy source. Among them, the problem of battery gas production has always been a focus of attention. The gas produced by the battery can easily cause safety problems such as explosion and fire. By detecting the gas situation inside the battery, timely warnings can be given. The sensing principle of existing gas sensors generally requires oxygen, which limits their application in detecting gas under anaerobic conditions. However, most battery cells are in an anaerobic or low-oxygen environment. Therefore, there is an urgent need to develop new materials and sensors that can respond to gas under non-oxygen conditions. The above statements are only used to provide background technical information related to this application and do not necessarily constitute prior art.

[0005] Summary of the Invention

[0006] The main technical problem solved by this application is to provide a battery, a gas sensing material and a preparation method thereof, a sensor and an electrical device, which can realize gas detection in an oxygen-free or low-oxygen environment, thereby realizing the detection of gas production inside the battery.

[0007] To solve the above technical problems, the present application adopts a technical solution: providing a battery, the battery including a gas sensor, the gas sensor including a gas sensing material, the gas sensing material including an M / MXene composite material, the composite material including metal (M) single atoms and MXene material, or in other words, the metal M in the M / MXene composite material is composited with the MXene material in the form of single atoms; and / or the M / MXene composite material including metal (M) clusters and MXene material, or in other words, the metal M in the M / MXene composite material is composited with the MXene material in the form of clusters. This gas sensing material is a chemical resistance sensing material that achieves detection by relying on changes in conductivity when the gas sensing material adsorbs and desorbs gas, enabling the gas sensing material to detect gas in an oxygen-free or low-oxygen environment, thereby realizing the detection of gas production inside the battery.

[0008] Furthermore, due to the adjustability of the electronic structure of metal M and the exposure of active sites, it can serve as a reaction center for binding to gas molecules, accelerate the charge transfer rate between gas molecules and M / MXene composite materials, increase the active sites for gas-solid surface reactions, and thus improve the response sensitivity of the gas sensing material, reduce the detection limit, enhance the selectivity, and quickly recover the response.

[0009] In one embodiment, the M / MXene composite material includes a metal (M) nitrogen-carbon compound, which is supported on the surface of the MXene material. In other words, the metal M in the M / MXene composite material is supported on the surface of the MXene material in the form of a metal nitrogen-carbon compound. This arrangement allows the metal M to form a strong interaction with the support (MXene), thereby stably fixing the metal M on the surface of the MXene material, forming a stable M / MXene composite material.

[0010] In one embodiment, each metal atom M in the metal carbon nitride is bonded to four nitrogen atoms. This arrangement allows the metal carbon nitride to possess electronic structural characteristics similar to those of precious metals, forming an interfacial confinement structure with MXene. This enhances sensing performance through the electron spillover effect, resulting in a composite material with more active sensing properties, high sensitivity, good selectivity, and a simple preparation process.

[0011] In one embodiment, the metal nitrogen-carbon compound includes a graphite structure, nitrogen atoms bonded to metal atoms are embedded in the graphite layer and bonded to the carbon atoms of the graphite layer, and the graphite is bound to the surface of the MXene material. In other words, the carbon atoms in the metal nitrogen-carbon compound exist in the form of graphite, nitrogen atoms bonded to metal atoms are embedded in the graphite layer and bonded to the carbon atoms of the graphite layer, and the graphite is bound to the surface of the MXene material. By using the graphite layer as a carbon material carrier, a connection skeleton can be provided for the metal group, allowing the metal group to complete the loading. The multi-level pore structure of the graphite layer can also provide more binding sites for gas molecules, increasing the location where the gas binding reaction occurs.

[0012] In one embodiment, the metal nitrogen carbon compound is doped with an element X, where X includes one or more of sulfur, phosphorus, and boron. Due to the difference in electronegativity of the doping elements, the conductivity and gas adsorption properties of the gas sensing material can be adjusted by doping.

[0013] In one embodiment, each metal atom M in the metal carbon nitrogen compound is bonded to four nitrogen atoms, and the doped X element replaces one or more of the four nitrogen atoms bonded to the metal atom M. This arrangement optimizes the structure of the central metal atom, thereby improving the sensitivity, selectivity, and stability of the sensor.

[0014] In one embodiment, the metal (M) in the M / MXene composite material is embedded in the MXene structure as a single atom; in other words, the metal M in the M / MXene composite material is embedded in the MXene structure as a single atom. This arrangement pins the metal M to defect sites in the MXene as a single atom, facilitating the metal's single atomic presence and preventing aggregation. This allows for active sites at the atomic level, enabling quantum effects and resulting in high sensitivity and selectivity.

[0015] In one embodiment, the metal M includes one or more of Fe, Co, Ni, Mn, Cu, Zn, Cr, Pd, Pt, Au, Ag, Ir, and Ru. By selecting different metals M, the response sensitivity and selectivity of gas sensing can be adjusted.

[0016] In one embodiment, the metal M includes one or more of Fe, Co, and Ni. By selecting different metals M, the response sensitivity and selectivity of gas sensing can be adjusted.

[0017] In one embodiment, the size of metal single atoms in the M / MXene composite material is less than 1 nm; and / or the size of metal clusters in the M / MXene composite material is 1-50 nm.

[0018] By setting the size of metal single atoms and metal clusters within the nanoscale range, it is beneficial to increase the adsorption sites, improve the activity of the adsorption sites, increase the efficiency of binding with gas molecules, and improve the sensitivity of the gas sensing material.

[0019] In one embodiment, the size of metal atoms in the M / MXene composite is less than 0.5 nm, and / or the size of metal clusters in the M / MXene composite is 10-30 nm. Setting the size of metal atoms and metal clusters within the nanoscale range helps increase adsorption sites, improve adsorption site activity, increase the efficiency of gas molecule binding, and enhance the sensitivity of the gas sensing material.

[0020] In one embodiment, the atomic content (at%) of the metal element M is less than or equal to 15% based on the total atomic count of the M / MXene composite. By selecting the atomic content of the metal element M, the sensitivity and selectivity of the gas sensing material can be adjusted. Depending on the application scenario, sensitivity or selectivity can be prioritized, and a trade-off between the two can be made to meet the requirements of the specific application.

[0021] In one embodiment, the atomic content (at%) of the metal element M is less than or equal to 10% based on the total atomic count of the M / MXene composite. By selecting the atomic content of the metal element M, the sensitivity and selectivity of the gas sensing material can be adjusted. Depending on the application scenario, sensitivity or selectivity can be prioritized, and a trade-off between the two can be made to meet the requirements of the specific application.

[0022] In one embodiment, the atomic content (at%) of the M element is less than or equal to 5% based on the total atomic count of the M / MXene composite material. By selecting the atomic content of the M element, the sensitivity and selectivity of the gas sensing material can be adjusted. Depending on the application scenario, sensitivity or selectivity can be prioritized, and a trade-off between the two can be made to meet the requirements of the specific application.

[0023] In one embodiment, the MXene material comprises M' n+1 X' n T x , where M' is an early transition metal element, X' n is carbon or nitrogen, T x OH - , O 2- 、F - By selecting MXene materials as the substrate of the composite material, a wide range of binding sites can be provided for the metal M. At the same time, the large number of surface functional groups of MXene materials can provide abundant active sites for gas adsorption and surface reactions.

[0024] In one embodiment, the gas sensing material responds to one or more of CO, NO2, NO, H2, CH4, H2S, ethylene, ethane, volatile organic compounds, and volatile electrolytes. By responding to these gases, the gas sensing material can adaptably meet different gas detection requirements, thereby expanding the application range of the gas sensing material.

[0025] In one embodiment, the volatile organic compound includes any one of methanol, formaldehyde, toluene, styrene, phenol, and benzene. By responding to the above gases, the gas sensing material can adaptably meet different gas detection requirements, thereby expanding the application range of the gas sensing material.

[0026] In one embodiment, the volatile electrolyte includes any one of a polyether electrolyte and a polyester electrolyte. By responding to the above gases, the gas sensing material can adaptably meet different gas detection requirements, thereby expanding the application range of the gas sensing material.

[0027] In one embodiment, the gas sensing material has a sensing response to gas within a temperature range of -55°C to 65°C. In this case, the gas sensing material can adapt to the operating temperature of most batteries, reducing the problem of gas sensing material failure caused by ambient temperature, and facilitating the gas sensing material's adaptation to different operating environments.

[0028] To solve the above technical problems, another technical solution adopted in this application is to provide a gas sensing material, including an M / MXene composite material, wherein the composite material includes metal (M) single atoms and MXene material, or in other words, the metal M in the M / MXene composite material is composited with the MXene material in the form of single atoms; and / or the M / MXene composite material includes metal (M) clusters and MXene material, or in other words, the metal M in the M / MXene composite material is composited with the MXene material in the form of clusters. This gas sensing material is a chemical resistance sensing material that achieves detection by relying on changes in conductivity when the gas sensing material adsorbs and desorbs gas, enabling the gas sensing material to detect gas in an oxygen-free or low-oxygen environment, thereby realizing the detection of gas production inside the battery.

[0029] To address the above technical issues, another technical solution adopted in this application is to provide a method for preparing a gas sensing material, comprising: providing a composite of MXene and a metal-organic complex, wherein the metal-organic complex is a complex of a metal M and an organic ligand; calcining the composite to obtain an M / MXene composite material, wherein the metal M is complexed with the MXene material in the form of single atoms; and / or wherein the metal M is complexed with the MXene material in the form of clusters. The gas sensing material prepared by the above method is capable of detecting gases in an oxygen-free or low-oxygen environment.

[0030] In one embodiment, calcining the composite includes calcining at a temperature of 700-1000° C. and / or calcining for 1-4 hours. Within this temperature and time range, the organic components in the metal-organic complex undergo pyrolysis and carbonization to form porous carbon with a graphite phase structure. Simultaneously, some metal ions in the metal-organic complex framework volatilize at high temperatures, forming defects and active sites.

[0031] In one embodiment, calcining the composite includes calcining the composite under a protective gas atmosphere, wherein the protective gas comprises one or more of argon, hydrogen, and nitrogen. Introducing the protective gas during the calcination step helps reduce oxidation during the reaction, helps preserve the activity of active sites on the material surface, and improves product quality.

[0032] In one embodiment, the composite is calcined in a doping gas atmosphere, wherein the doping gas includes one or more of ammonia and hydrogen sulfide. This provides protection for the reaction and also allows the introduction of doping elements to optimize the sensing performance of the gas sensing material and enhance its adaptability to various application requirements.

[0033] In one embodiment, providing a composite of a MXene and a metal-organic complex includes mixing a metal-organic complex solution with a MXene solution, stirring the mixture, and reacting the mixture to obtain the composite. This reaction produces a composite of a MXene and a metal-organic complex, which serves as a precursor to the M / MXene composite material and a prerequisite for the final M / MXene composite material.

[0034] In one embodiment, mixing the metal-organic complex solution with the MXene solution includes dropwise adding the MXene solution to the stirred metal-organic complex solution at a rate of 1-20 seconds per drop. The stirring state facilitates sufficient contact between the MXene solution and the metal-organic complex solution, accelerating the reaction rate. By controlling the dropwise addition rate, the concentration of the solution in the reaction zone can be adjusted, facilitating the formation of well-dispersed, uniformly sized crystals.

[0035] In one embodiment, before mixing the metal-organic complex solution with the MXene solution, the steps include: combining the metal-organic complex with a surfactant; and / or combining the MXene material with a surfactant. Incorporating a surfactant into the metal-organic complex or MXene improves the interfacial affinity between the metal-organic complex and the MXene, promoting a more efficient reaction. Furthermore, it facilitates uniform dispersion of the metal-organic complex and MXene in the solution, thereby enhancing the uniformity and stability of the reaction.

[0036] In one embodiment, the surfactant includes cetyltrimethylammonium bromide. Using cetyltrimethylammonium bromide as a surfactant facilitates the bonding of the metal-organic complex and the MXene. Furthermore, the positive ions of cetyltrimethylammonium bromide attract the negatively charged functional groups (e.g., -OH, -F) on the MXene and the negative charges on the surface of the metal-organic complex, thereby improving the stability of the bond.

[0037] In one embodiment, combining a metal-organic complex with a surfactant includes: providing a metal-organic complex precursor and cetyltrimethylammonium bromide; and mixing the metal-organic complex precursor and cetyltrimethylammonium bromide to react, thereby obtaining a metal-organic complex combined with cetyltrimethylammonium bromide. The positive ions of cetyltrimethylammonium bromide attract the negative surface charges of the metal-organic complex, forming an adsorption layer. The hydrophobic alkyl chains of cetyltrimethylammonium bromide interact with the hydrophobic regions of the metal-organic complex, further stabilizing the adsorption layer. This combination can help disperse and stabilize the metal-organic complex and regulate its properties.

[0038] In one embodiment, doping and modifying a metal-organic complex includes providing a metal-organic complex precursor and a doping precursor; and mixing and reacting the metal-organic complex precursor and the doping precursor to obtain a doped and modified metal-organic complex. This arrangement effectively achieves the purpose of doping, enabling the doping of multiple elements, thereby purposefully modifying gas sensing materials and broadening the application range of gas sensing materials.

[0039] To solve the above technical problems, another technical solution adopted by this application is to provide a gas sensor comprising any of the above-mentioned gas sensing materials, or comprising a gas sensing material produced by any of the above-mentioned methods. Through the above-mentioned configuration, gas detection can be performed in an oxygen-free or low-oxygen environment.

[0040] To solve the above technical problems, another technical solution adopted by the present application is to provide an electrical device comprising the above battery. The electrical device has at least the same advantages as the battery.

[0041] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0043] FIG1 is a high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) image of a gas sensing material according to one or more embodiments;

[0044] FIG2 is a transmission electron microscope (TEM) image of a gas sensing material according to one or more embodiments;

[0045] 3 is a high-angle annular dark field scanning transmission electron microscope (HAADF-STEM EDS) image of a gas sensing material according to one or more embodiments;

[0046] FIG4 is a synchrotron X-ray absorption spectroscopy (XAFS) diagram of a gas sensing material according to one or more embodiments;

[0047] FIG5 is a synchrotron X-ray absorption spectroscopy (XAFS) of a gas sensing material according to one or more embodiments;

[0048] FIG6 is a synchrotron X-ray absorption spectroscopy (XAFS) graph of a gas sensing material according to one or more embodiments;

[0049] FIG7 is an X-ray diffraction pattern (XRD) of a gas sensing material according to one or more embodiments;

[0050] FIG8 is a schematic diagram of a reaction process for preparing a gas sensing material according to one or more embodiments;

[0051] FIG9 is a schematic diagram of a gas sensing performance test according to one or more embodiments;

[0052] FIG10 is a schematic diagram illustrating gas response of Ni / MXene, a gas sensing material, according to one or more embodiments;

[0053] FIG11 is a schematic diagram illustrating gas response of Ni / MXene, a gas sensing material, according to one or more embodiments;

[0054] FIG12 is a schematic diagram illustrating gas response of Ni / MXene, a gas sensing material, according to one or more embodiments;

[0055] FIG13 is a schematic diagram illustrating gas response of Ni / MXene gas sensing material according to one or more embodiments;

[0056] FIG14 is a schematic diagram illustrating gas response of Fe / MXene gas sensing materials according to one or more embodiments;

[0057] FIG15 is a schematic diagram illustrating gas response of a gas sensing material Co / MXene according to one or more embodiments;

[0058] FIG16 is a schematic diagram illustrating gas response of Ni / MXene, a gas sensing material, according to one or more embodiments;

[0059] FIG17 is a schematic diagram of an exploded structure of a battery according to one or more embodiments;

[0060] FIG18 is a schematic diagram of an exploded structure of a battery cell according to one or more embodiments;

[0061] FIG19 is a schematic structural diagram of a vehicle according to one or more embodiments.

[0062] In the attached figure:

[0063] 1000, vehicle; 300, motor; 200, controller; 100, battery; 10, housing; 11, first part; 12, second part; 20, battery cell; 21, end cap; 21a, electrode terminal; 22, housing; 23, electrode assembly. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solution and effect of this application clearer and more specific, the following embodiments of the technical solution of this application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of this application and are therefore only examples and are not intended to limit the scope of protection of this application.

[0065] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0066] In the description of the embodiments of the present application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two), similarly, "multiple groups" refers to more than two (including two), and "multiple pieces" refers to more than two (including two), unless otherwise clearly and specifically defined.

[0067] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0068] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0069] Amounts, ratios, and other numerical values ​​are presented herein in a range format. It should be understood that such range format is used for convenience and brevity and should be interpreted flexibly to include not only the values ​​explicitly specified as range limits, but also all individual values ​​or sub-ranges encompassed within the range, as if each value and sub-range were explicitly specified.

[0070] If not otherwise specified, all steps of the present application may be performed sequentially, randomly, or in parallel, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially, or may include steps (a) and (b) performed simultaneously in parallel. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b), and (c), or may include steps (a), (c), and (b), or may include steps (c), (a), and (b), etc.

[0071] Batteries have a wide range of applications in the new energy sector, primarily in electric vehicles, energy storage systems, and renewable energy. In the electric vehicle sector, lithium-ion batteries are the mainstream technology. Their high energy density, long lifespan, and fast charging characteristics enable electric vehicles to achieve longer driving range and higher performance. In energy storage systems, batteries are widely used for large-scale and distributed energy storage. They can balance grid loads, store renewable energy sources such as solar and wind power, and release the stored energy during peak periods. Furthermore, small rechargeable batteries are widely adopted in applications such as wearable devices, drones, and smart homes. Battery technology development focuses on increasing energy density, extending lifespan, reducing costs, and focusing on environmental friendliness. With the growing demand for clean energy and sustainable development, the application of batteries in the new energy sector will continue to expand, driving further progress in the energy transition.

[0072] As the battery charges and discharges, some side reactions generate gases. If these gases are not promptly discharged, the internal pressure of the battery will rise, exceeding normal levels. Excessive internal pressure can negatively impact the battery's performance and appearance. In severe cases, this can lead to destructive effects, such as leakage, bulging, increased internal resistance, and shortened discharge time and cycle life. Furthermore, batteries can be subject to abnormal operation during use, including overcharging, over-discharging, and internal faults. In these cases, the chemical reactions within the battery may become uncontrolled, accompanied by a violent release of gas, and even trigger thermal runaway. Battery thermal runaway refers to a chain reaction phenomenon triggered by various factors. The large amount of heat and harmful gases emitted by thermal runaway can cause the battery to catch fire and explode.

[0073] In order to monitor the gas production of the battery in a timely manner, the research found that a gas sensor can be installed inside the battery. Specifically, characteristic gases are generated when the battery is working or thermally runaway. For example, ethylene carbonate, an electrolyte component in lithium batteries, undergoes oxidation and decomposition on the positive electrode side to produce carbon monoxide and carbon dioxide, and undergoes reduction reaction on the negative electrode side to produce carbon monoxide and methane. By detecting characteristic gases that exceed the concentration threshold and issuing an alarm in time, measures can be taken at the early stage when the internal pressure of the battery exceeds the normal level to reduce the occurrence of safety accidents. However, existing gas sensors have defects in battery gas production detection. For example, electrochemical sensors must be used in an oxygen environment because their working principle is based on reversible oxidation-reduction reactions. In the actual scenario of battery gas detection, the inside of the battery is generally oxygen-free or low in oxygen, which limits the application of such gas sensors. For example, infrared sensors do not rely on oxygen in their working process, but their detection sensitivity for low-concentration gases needs to be improved.

[0074] Based on the above considerations, in order to solve the problem that gas production monitoring in batteries relies on oxygen and the detection sensitivity of low-concentration gases is low, the present application designs a gas sensing material. By compounding the metal element M in the form of a single atom or cluster with a MXene material, an M / MXene composite material is prepared. This gas sensing material is a chemical resistance sensing material. It relies on the change in conductivity when the gas sensing material interacts with the adsorption and desorption of gases to achieve the detection purpose, so that the gas sensing material can respond to one or more gases including carbon monoxide (CO), nitrogen dioxide (NO2), nitric oxide (NO), hydrogen (H2), methane (CH4), hydrogen sulfide (H2S), ethylene, ethane, volatile organic compounds, and volatile electrolytes in an oxygen-free or low-oxygen environment.

[0075] According to some embodiments of the present application, a battery is disclosed, comprising a gas sensor, wherein the gas sensor comprises a gas sensing material, wherein the gas sensing material is an M / MXene composite material, wherein the metal M in the M / MXene composite material is compounded with the MXene material in the form of single atoms; and / or the metal M is compounded with the MXene material in the form of clusters. That is, all the metal M in the M / MXene composite material may exist in the form of single atoms, all the metal M in the M / MXene composite material may exist in the form of clusters, or some of the metal M in the M / MXene composite material may exist in the form of single atoms, while some of the metal M exists in the form of clusters. The gas sensing material may be a mixture of one or more of the aforementioned multiple M / MXene composite materials.

[0076] Among them, MXene materials include M' n+1 X' n T x , where M' is an early transition metal element, X' is carbon or nitrogen, T x Hydroxyl (OH - ), oxygen negative ions (O 2- ), fluoride ion (F - ) groups.

[0077] Among them, n=1-3, early transition metal elements include titanium (Ti), zirconium (Zr), vanadium (V), molybdenum (Mo), etc. x Represents surface functional groups. MXene materials are a class of two-dimensional inorganic compounds composed of transition metal carbides, nitrides or carbonitrides with a thickness of several atomic layers. MXene is usually prepared by selectively etching the A layer elements using the MAX phase as a precursor or a molten salt method. The MAX phase is a class of ternary layered compounds. The M in the MAX phase represents a transition metal element, A represents a IIIA or IVA group element such as aluminum (Al), silicon (Si), and tin (Sn), and X represents carbon or nitrogen. MXene has advantages such as high specific surface area, excellent conductivity, and stable mechanical properties due to its graphene-like two-dimensional layered structure. MXene can be Ti3C2T x 、Ti2CT x 、Nb2CT x 、Ti3CNT x 、TiVCT x wait.

[0078] By selecting MXene materials as the base material of the composite material, the extremely high specific surface area and excellent conductivity characteristics of the MXene matrix, as well as the abundant active sites on the MXene surface, can be utilized to provide a wide range of binding sites for metal M; at the same time, the large number of surface functional groups of the MXene material can provide abundant active sites for gas adsorption and surface reactions.

[0079] The metal M complexed with the MXene material in the form of a single atom means that the metal is loaded on the surface of the support (MXene) in the form of a single atom, or is pinned and embedded in the support (MXene) in the form of a single atom. This can be achieved by bonding with heteroatoms on the surface of the support (MXene) or by pinning into defect sites in the support (MXene).

[0080] Please refer to Figure 1, which is a high-angle annular dark field scanning transmission electron microscope (HAADF-STEM) image of a gas sensing material according to one or more embodiments. Figure 1 shows that the metal atoms exist in a monodisperse state, and the figure shows bright isolated metal single atom points. In this composite material, the metal component is reduced to the single-atom scale, and the size of the metal single atom can be less than 1nm; in one embodiment, the size of the metal single atom is less than 0.5nm. Metal single atoms have the characteristics of maximizing atomic utilization and isolated active sites, which can increase the number of adsorption sites, increase the adsorption area, and thereby improve the gas response sensitivity and reduce the response time. Furthermore, the size of the active site is reduced to the single-atom size, which can exert quantum effects and have the characteristics of high sensitivity and high selectivity.

[0081] Atomic clusters are relatively stable microscopic and submicroscopic aggregates composed of several or even thousands of atoms bonded together physically or chemically. Metal M composites with MXene materials in the form of clusters mean that the metal components in the composite material are not necessarily dispersed as single atoms; they can also be composed of multiple atoms in clusters.

[0082] Refer to Figure 2, which is a transmission electron microscope (TEM) image of a gas sensing material according to one or more embodiments. Figure 2 shows multiple metal atoms present in clusters, specifically the circled nanoclusters. The metal atoms can exist in multiple clusters, and the sizes of the multiple atomic clusters can vary, ranging from 1 to 50 nm; for example, they can be 2 nm, 5 nm, 8 nm, 10 nm, 20 nm, 30 nm, 50 nm, etc.

[0083] In one embodiment, the size of the metal clusters in the M / MXene composite material is 10-30 nm; for example, it can be 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, etc.

[0084] In this way, the metal atom clusters possess a very high specific surface area and surface energy, making the surface atoms highly active. Consequently, they are chemically unstable and easily bind to other atoms, and thus gas molecules, ultimately increasing the sensitivity of the gas sensing material. Furthermore, the atomic clusters can also increase the loading capacity of the metal M in the composite material.

[0085] By using M / MXene composite materials as gas sensing materials, in which metal M is compounded with MXene materials in the form of single atoms and / or clusters, the electrochemical properties of MXene materials can be improved. At the same time, the adjustability of the electronic structure of metal M and the exposure of active sites can serve as reaction centers for binding to gas molecules, accelerate the charge transfer rate between gas molecules and M / MXene composite materials, increase the active sites for gas-solid surface reactions, thereby improving the response sensitivity of the gas sensing material, reducing the detection limit, and enhancing the selectivity. When applied to batteries, it can realize the detection of gas production inside the battery, improve the safety performance of the battery, and extend the service life of the battery.

[0086] According to some embodiments of the present application, the metal M in the M / MXene composite material is embedded in the structure of the MXene material in the form of a single atom. Specifically, the metal M can be pinned in the defect site of the MXene in the form of a single atom.

[0087] Among them, single atoms are prone to agglomeration due to their higher surface free energy. In order to overcome the tendency of single atoms to agglomerate, single atoms can be anchored by forming a strong chemical interaction between the single atoms and the carrier. On the one hand, defect engineering can be used to create defects on the carrier, and the defects can be used to fix metal single atoms. This is because compared with the complete carbon lattice, intrinsic defects, such as edge sites and in-plane topological defects, will cause charge localization by forming more electronic states near the Fermi level. Therefore, intrinsic defects are also considered to be an important type of anchoring site to obtain single-atom materials. Polyatomic vacancies capture transition metal atoms with larger radii and are able to maintain stability. Based on this, in one embodiment of the present application, defect sites can be created on MXene and then compounded with metal M so that metal M is pinned to the defect sites of MXene in a single-atom state.

[0088] On the other hand, doped heterogeneous non-metallic atoms can be used to anchor single metal atoms. Heterogeneous non-metallic atoms can serve as additional coordination sites to anchor single metal atoms, thereby achieving high loading capacity. Surface unsaturated sites on metal compounds can stabilize atoms by forming strong chemical bonds with atoms. The type, number, and uniformity of surface unsaturated sites affect the loading capacity of single metal atoms. The different characteristics of the anchoring sites directly affect the electronic structure of the single metal site, thereby affecting the gas response performance of the single atom.

[0089] Heterogeneous atoms can achieve electronic structure regulation of active metal center sites, and can also significantly change the long-range atomic arrangement and electronic structure of the carrier. Heterogeneous non-metallic atoms can be oxygen (O), carbon (C), nitrogen (N), sulfur (S), phosphorus (P), etc., which can serve as connecting atoms to form chemical bonds with metal single atoms to form stable metal single atom sites. Based on this, in one embodiment of the present application, the metal atom can be connected to the surface of the carrier by bonding with the coordinating atoms on the carrier. According to some embodiments of the present application, the metal M in the M / MXene composite material is loaded on the surface of the MXene material in the form of a metal nitrogen-carbon compound.

[0090] Please refer to Figures 3 and 4. Figure 3 is a high-angle annular dark field scanning transmission electron microscope (HAADF-STEM EDS) image of a gas sensing material according to one or more embodiments. Figure 4 is a synchrotron radiation X-ray absorption spectrum (XAFS) graph of a gas sensing material according to one or more embodiments. In this embodiment, nickel (Ni) and MXene (Ti3C2T x) composite material as an example, the energy spectrum was captured using a JEOLARM 200F instrument at 200kV. As can be seen from the energy spectrum shown in Figure 3, the composite material contains nickel (Ni), nitrogen (N), carbon (C), and titanium (Ti), and the nickel (Ni) is evenly distributed. Furthermore, XAFS spectra of the Ni K edge were collected in fluorescence mode on the XAFCA beamline of the Singapore Synchrotron Light Source (SSLS), using Ni foil (Ni foil), nickel oxide (NiO), Ni nanoparticles (Ni NPs / NC), and a Ni-NC reference (a compound in which a known metal M is formed in the form of a metal nitrogen-carbon compound) as references. Among them, the reference examples of Ni foil (Ni foil) and Ni nanoparticles (Ni NPs / NC) are to provide a reference for the absorption peak of Ni-Ni bond to prove whether there is a Ni-Ni bond in the composite material; the reference example of nickel oxide (NiO) is to provide a reference for the absorption peak of Ni-O bond to prove whether there is a Ni-O bond in the composite material; the reference example of Ni-NC reference is to provide a reference for the absorption peak of Ni-N / C bond to prove whether there is a Ni-N / C bond in the composite material. As can be seen from Figure 4, compared with Ni foil, nickel oxide and Ni nanoparticles, the Ni / MXene composite material has no absorption peaks at the peak positions of Ni-Ni bond and Ni-O bond, indicating that there is no Ni-Ni bond in the Ni / MXene composite material and Ni exists in the form of a single atom; compared with Ni-NC, the Ni / MXene composite material has a clear absorption peak at the peak position of Ni-N bond, indicating that Ni and N in the Ni / MXene composite material are bonded to form a metal nitride, which is hereinafter referred to as MN x express.

[0091] By combining metal M with nitrogen atoms to form bonds, metal M can form a strong interaction with the carrier, so that metal M can be stably fixed on the surface of the MXene material to form a stable M / MXene composite material.

[0092] According to some embodiments of the present application, each metal atom M in the metal nitrogen-carbon compound is bonded to four nitrogen atoms.

[0093] Please refer to Figures 3 to 6. Figure 5 is a synchrotron radiation X-ray absorption near edge structure (XANES) spectrum of the gas sensing material according to one or more embodiments. It can be seen from Figure 5 that the valence state of Ni is between 0 and +2. This indicates that nickel compounds are formed, not in the form of clusters (0 valence). In nickel compounds, nickel atoms lose two 4s electrons to form Ni 2+ ion, whose electronic structure is [Ar]3d ^8. FIG6 is a synchrotron radiation X-ray absorption spectrum (XAFS) diagram of the gas sensing material according to one or more embodiments. From the absorption peak of Ni and N bonding in FIG6, it can be seen that the coordination number of Ni and N is 4, that is, each metal atom M is bonded to four nitrogen atoms, which is denoted by MN4 below. At the same time, according to the chemical structure of Ni-NC / Ti3C2T x The XAFS spectra of the composite were theoretically fitted, and the actual test results coincided with the theoretical fit, confirming the configuration of the Ni in the composite material, as shown in the chemical structure in Figure 6, where each Ni is bonded to four single atoms. Different atomic numbers and coordination structures can induce changes in the electronic structure of the metal active sites, leading to differences in gas sensing responsiveness and selectivity.

[0094] In this embodiment, the metal nitrogen compound (MN4) has the electronic structure characteristics of precious metals (Pd, Pt). Through the platinum-like electronic structure, the active sites of MN4 are connected to the substrate MXene (Ti3C2T x ) form an interfacial confinement structure, which in turn creates a confinement effect between the substrates. This allows for both chemical and electronic sensitization sensing mechanisms, and enhances sensing performance through an electron spillover effect. Specifically, in this electron spillover effect, electrons from the metal center can be transferred to molecules adsorbed on the surface, resulting in a composite material with more active sensing properties, high sensitivity, and good selectivity.

[0095] The electron spillover effect is typically related to the electron density of the metal center, the adsorption pattern of gas molecules, and the interaction between metal and gas molecules. This gives metal nitrogen carbon compounds a highly tunable electronic structure. Therefore, by adjusting the electron density of the metal center and the adsorption pattern of gas molecules, gas sensing performance can be optimized and controlled, improving the selectivity and sensitivity of gas sensing materials to the response gas.

[0096] According to some embodiments of the present application, the carbon atoms in the metal nitrogen-carbon compound exist in the form of graphite, the nitrogen atoms bonded to the metal atoms are embedded in the graphite layer and bonded to the carbon atoms in the graphite layer, and the graphite is combined with the surface of the MXene material.

[0097] Please refer to FIG7 , which is an X-ray diffraction pattern (XRD) of a gas sensing material according to one or more embodiments. In this embodiment, nickel (Ni) and MXene (Ti3C2T xX-ray diffraction tests were performed using composite materials made of NC, Ni-NC, and Ni NPs / NC as references. NC is a non-Ni-doped NC material synthesized by directly calcining ZIF-8. Ni-NC is a nickel-nitrogen carbon compound synthesized by calcining nickel nitrate with ZIF-8. Ni NPs / NC is a nickel nanoparticle / carbon compound synthesized by calcining nickel nitrate with ZIF-8. The difference between Ni-NC and Ni-NC lies in the different ratios of nickel nitrate.

[0098] From Figure 7, it can be seen that the spectrum of Ni / MXene composite material includes Ti3C2T with 2θ=6.2°. x The characteristic diffraction peak of graphite appears around 2θ=26.4°.

[0099] By using graphite layers as a carbon material carrier, they provide a connecting framework for the MN4 groups, enabling them to be loaded and then bonded to the MXene through the graphite. Furthermore, the multi-level pore structure of the graphite layers provides more binding sites for gas molecules, increasing the number of locations for gas binding reactions to occur. Furthermore, graphite can enhance the volume density, electrical conductivity, corrosion resistance, and machinability of the carbon material carrier, thereby improving the electrical conductivity of the gas sensing material.

[0100] According to some embodiments of the present application, the metal nitrogen-carbon compound is doped with an X element, where X includes one or more of sulfur (S), phosphorus (P), and boron (B).

[0101] The doped X element is a non-metallic element that forms coordinated bonds with the metal M and carbon (C) atoms, trapping atomically dispersed metal sites and preventing them from being lost or released. The electronegativity of elements like sulfur, phosphorus, and boron differs significantly from that of carbon and nitrogen, meaning their inclusion can introduce additional charge distribution or polarity, altering the material's electronic structure and modifying single-atom properties. Furthermore, this difference in electronegativity can modulate the material's electrical conductivity and gas adsorption properties, ultimately adjusting the gas sensing response.

[0102] Furthermore, each metal atom M in the metal nitrogen-carbon compound is bonded to four nitrogen atoms, and the doped X element replaces one or more of the four nitrogen atoms bonded to the metal atom M.

[0103] According to ligand field theory, the bonding of metal complexes is similar to the interaction between positive and negative ions in ionic crystals: first, the interaction between the metal and the ligand is electrostatic, with the ligand considered a point charge; second, the ligand establishes a negative charge potential field, which, under the perturbation of the negative charge potential field, causes the metal's d orbital energy levels to split; third, the metal's electrons fill the split d orbitals from low to high, causing the total energy to decrease and generating an additional bonding effect. Therefore, ligands influence the electronic d orbitals of the central metal atom M they surround. The strength of the interaction between the metal atom and the ligand determines the rise and fall of different d orbitals in level. Therefore, the electronic structure and gas sensing performance of metal nitrogen carbon compounds can be controlled by adjusting the ligands around the central metal atom.

[0104] The doping element acts as a coordination atom at the center of the metal atom to replace the MN x By adjusting the position of some or all of the nitrogen atoms in the sensor and constructing different ligand types, the structure of the central metal atom can be optimized, thereby improving the sensitivity, selectivity and stability of the sensor.

[0105] According to some embodiments of the present application, the metal M includes one or more of iron (Fe), cobalt (Co), nickel (Ni), manganese (Mn), copper (Cu), zinc (Zn), chromium (Cr), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), iridium (Ir), and ruthenium (Ru).

[0106] In one embodiment, the metal M includes one or more of Fe, Co, and Ni.

[0107] The metal M is a transition metal. Transition metals have a unique electronic structure, with unfilled valence d orbitals and a high charge-to-radius ratio, making them prone to forming stable coordination compounds with ligands. Furthermore, different metals have different electronic structures, resulting in differences in their binding to gas molecules.

[0108] The metal M is dispersed in the composite material as single atoms or clusters. The metal atoms and their local coordination environment constitute the metal single atomic sites. The active sites of each metal atom are not necessarily identical. Inhomogeneities in the support surface can lead to heterogeneous coordination environments around the single atoms and variations in intrinsic activity. The atomically dispersed metal and its surrounding coordination environment play a crucial role in determining activity, selectivity, and stability. The sensitivity and selectivity of gas sensing can be tuned by selecting different metal elements.

[0109] In one embodiment, a composite material may contain multiple different types of metal atoms, such as Fe and Ni. The different metals can be dispersed on a support as single atoms or clusters. Alternatively, they can form single-atom alloys, in which the non-metallic support is replaced by a metal support, with the active metal atoms interacting with the support via metal-metal bonds.

[0110] According to some embodiments of the present application, the atomic content (at%) of the M element is less than or equal to 15% based on the total number of atoms in the M / MXene composite material. For example, it can be 1%, 2%, 5%, 8%, 10%, 12%, 15%, etc., or a range consisting of any two of the above values, such as 1%-2%, 2%-5%, 5%-8%, 8%-10%, 10%-12%, 12%-15%, etc.

[0111] In one embodiment, the atomic content (at%) of the element M is less than or equal to 10%, for example, 1%, 2%, 5%, 8%, 10%, or a range consisting of any two of the above values, for example, 1%-2%, 2%-5%, 5%-8%, 8%-10%, etc.

[0112] In one embodiment, the atomic content (at%) of the element M is less than or equal to 5%, for example, 0.1%, 1%, 2%, 5%, etc., or a range consisting of any two of the above values, for example, 0.1%-2%, 1%-2%, 2%-5%, etc.

[0113] The atomic content of an element refers to the percentage of its atoms in the total atomic count of the material. The atomic content of the M element refers to the percentage of the M element's atoms in the total atomic count of the M / MXene composite. M atoms act as active centers for binding to gas molecules. Increasing the M atom content increases the number of active adsorption sites, thereby increasing the sensor's sensitivity to target gases. However, increasing the M atom content increases the likelihood of clustering, which may reduce sensing performance.

[0114] By selecting the atomic content of the M element, the sensitivity and selectivity of the gas sensing material can be adjusted. Depending on different application scenarios, sensitivity or selectivity can be prioritized, and a trade-off can be made between the two to meet the requirements of specific applications.

[0115] In some embodiments of the present application, the response gas of the gas sensing material includes any one of CO, NO2, NO, H2, CH4, H2S, ethylene, ethane, volatile organic compounds, and volatile electrolytes.

[0116] In one embodiment, the volatile organic compound includes any one of methanol, formaldehyde, toluene, styrene, phenol, and benzene.

[0117] In one embodiment, the volatile electrolyte includes any one of a polyether electrolyte and a polyester electrolyte.

[0118] During the normal operation of battery charging and discharging and when thermal runaway occurs, different types of batteries will produce different gases. For example, lead-acid batteries will produce hydrogen, lithium-ion batteries will produce carbon monoxide, carbon dioxide and hydrocarbon gases including methane, ethane and ethylene, etc. Sodium-ion batteries will also produce hydrogen, and lithium-sulfur batteries may produce hydrogen and hydrogen sulfide gas. In addition, a volatile electrolyte is an electrolyte commonly used in batteries or energy storage devices. It has high volatility and is usually an organic compound. In the event of a battery failure, the volatile electrolyte may evaporate and thermally decompose to produce gases including carbon monoxide, carbon dioxide and nitric oxide. The gas sensor provided in this application can be used to detect different gases in the above-mentioned different batteries.

[0119] In some embodiments of the present application, the gas sensing material is responsive to gases within a temperature range of -55°C to 65°C. This helps the gas sensing material adapt to different operating environments and reduces the problem of temperature-induced failure of the gas sensing material. In particular, the gas sensing material is able to still sense gases at relatively low temperatures, indicating that the gas sensing material is highly active and can adapt to extremely cold operating environments. This is of great significance to the safety performance of batteries used in special environments.

[0120] Conventional lithium-ion batteries operate at temperatures between -20°C and 60°C. However, performance and discharge capacity generally decrease below 0°C, so the typical operating temperature for lithium-ion batteries is 0°C to 40°C. Lead-acid batteries typically operate within a wider temperature range, roughly between -20°C and 50°C. Lithium-polymer batteries, like lithium-ion batteries, typically operate between -20°C and 60°C. Sodium-ion batteries typically operate between approximately -10°C and 60°C. Lithium-sulfur batteries typically operate between -20°C and 60°C. Similar to lithium-ion batteries, their performance may be limited in extreme temperature conditions.

[0121] While other existing gas sensing materials only respond to gases at temperatures of 80-90°C or even higher, making them unsuitable for battery systems, the gas sensing material provided in this application exhibits better response at low temperatures and has a gas response temperature range that matches the operating temperature of most batteries.

[0122] In the above embodiments, by selecting a composite of metal atoms or clusters with a carrier as the gas sensing material, gas detection in an oxygen-free or hypoxic environment can be achieved with high sensitivity, low detection limit, strong selectivity, and rapid response recovery. The composite of metal atoms or clusters with a carrier can be prepared by physical methods such as atomic layer deposition and physical / chemical vapor deposition, or by chemical methods such as co-deposition and pyrolysis.

[0123] In some embodiments of the present application, a gas sensing material is also provided, including an M / MXene composite material, wherein the composite material includes metal (M) single atoms and MXene material, or in other words, the metal M in the M / MXene composite material is composited with the MXene material in the form of single atoms; and / or the M / MXene composite material includes metal (M) clusters and MXene material, or in other words, the metal M in the M / MXene composite material is composited with the MXene material in the form of clusters. This gas sensing material is a chemiresistive sensing material that achieves detection by changes in electrical conductivity when the gas sensing material adsorbs and desorbs gas, enabling gas detection in an oxygen-free or low-oxygen environment, thereby enabling detection of gas production within the battery.

[0124] In some embodiments of the present application, a method for preparing a gas sensing material is also provided, comprising: providing a complex of MXene and a metal-organic complex, wherein the metal-organic complex is a complex of a metal M and an organic ligand; calcining the complex to obtain an M / MXene composite material, wherein the metal M in the M / MXene composite material is composited with the MXene material in the form of a single atom; and / or wherein the metal M in the M / MXene composite material is composited with the MXene material in the form of a cluster.

[0125] Metal-organic complexes are precursors of single metal atoms and metal clusters. Precursors containing metal nodes can be used to prepare single-atom complexes through pyrolysis. During calcination, these complexes are formed by pyrolysis to form single metal atoms and / or metal clusters. During high-temperature pyrolysis, strong interactions occur between the single atoms and the pyrolysis products, forming complexes.

[0126] Metal-organic complexes are typically complexes of metal ions with organic ligands, such as metal acetates, metal nitrates, metal chlorides, or organic complexes of metal-organic frameworks. During the calcination process, the metal ions are decomposed or reduced to metal atoms or metal clusters.

[0127] Among them, organic ligands are molecules or ions in organic compounds, usually containing elements such as carbon, hydrogen, oxygen, and nitrogen. Common organic ligands include ethylenediamine and dimethylimidazole. They can form coordination bonds with metal atoms to form metal-organic complexes. Furthermore, when preparing metal single-atom complexes, metal-organic complexes can also provide heterogeneous non-metallic atoms (carbon, nitrogen, etc.) to anchor metal single atoms and metal clusters, thereby forming stable metal atom sites.

[0128] In some embodiments of the present application, the metal M in the M / MXene composite material is supported on the surface of the MXene material in the form of a metal nitrogen-carbon compound. This type of composite is hereinafter referred to as an MNC / MXene composite material. Specifically, each metal atom M in the metal nitrogen-carbon compound is bonded to four nitrogen atoms, and the carbon atoms in the metal nitrogen-carbon compound exist in the form of graphite. The nitrogen atoms bonded to the metal atoms are embedded in the graphite layer and bonded to the carbon atoms in the graphite layer, and the graphite is bound to the surface of the MXene material. The MNC / MXene composite material can be prepared by calcining a composite of MXene and a metal organic complex.

[0129] In some embodiments of the present application, a composite of MXene and a metal-organic complex is first prepared. Specifically, a metal-organic complex solution and a MXene solution are mixed and stirred to react to obtain a composite of MXene and a metal-organic complex.

[0130] In some embodiments of the present application, before mixing the metal organic complex solution with the MXene solution, the steps include: combining the metal organic complex with a surfactant; and / or combining the MXene material with a surfactant.

[0131] Surfactants are substances that can significantly reduce the surface tension of the target solution. Surfactants have fixed hydrophilic and lipophilic groups that can be arranged in a direction on the surface of the solution. The molecular structure of surfactants is amphiphilic: one end is a hydrophilic group, and the other end is a hydrophobic group. The hydrophilic group is often a polar group, such as carboxylic acid, sulfonic acid, sulfuric acid, amino or amine groups and their salts. Hydroxyl groups, amide groups, ether bonds, etc. can also serve as polar hydrophilic groups; while the hydrophobic group is often a non-polar hydrocarbon chain, such as a hydrocarbon chain with more than 8 carbon atoms. Surfactants are divided into ionic surfactants (including cationic surfactants and anionic surfactants), non-ionic surfactants, amphoteric surfactants, compound surfactants, and other surfactants.

[0132] By mixing a surfactant with at least one of the metal-organic complex solutions before mixing them with the MXene solution, the surfactant is first attached to the metal-organic complex or MXene. The presence of the surfactant enables the metal-organic complex and MXene to be connected via hydrophilic and lipophilic groups during the reaction, acting as a bridge between the two. This helps improve the interfacial affinity between the metal-organic complex and the MXene, promoting a more efficient reaction. Furthermore, the surfactant acts as a dispersant, facilitating the uniform dispersion of the metal-organic complex and MXene in the solution, thereby enhancing the uniformity and stability of the reaction.

[0133] In one embodiment, the surfactant includes cetyltrimethylammonium bromide. Cetyltrimethylammonium bromide (CTAB) is a cationic surfactant with a hydrophilic-lipophilic balance (HLB) of 15.8. The CTAB molecular structure contains a hydrophobic alkyl chain (hexadecyl) that is lipophilic, while the ammonium bromide ion portion of the CTAB molecule is hydrophilic. This molecular structure makes CTAB both hydrophilic and lipophilic. The hydrophilic group of CTAB is connected to the MXene, and the lipophilic group is connected to the metal organic complex, thereby achieving a composite of the metal organic complex and MXene.

[0134] In addition, the CTAB molecule has a positive charge because the ammonium ion (NH 4+ ) carries a positive charge, which can interact with negatively charged surfaces or particles. By using CTAB as a surfactant, the positive ions of CTAB can attract the negatively charged functional groups (such as -OH and -F) on the MXene and the negative charges on the surface of the metal organic complex, thereby improving the stability of the connection.

[0135] Furthermore, in some embodiments of the present application, the metal organic complex is preferably combined with a surfactant, specifically comprising: providing a metal organic complex precursor and hexadecyltrimethylammonium bromide; mixing the metal organic complex precursor and hexadecyltrimethylammonium bromide to react to obtain a metal organic complex combined with hexadecyltrimethylammonium bromide.

[0136] As previously mentioned, the positive ions of CTAB attract the negative surface charges of metal-organic frameworks, forming an adsorption layer. This adsorption is typically achieved through electrostatic interactions. The hydrophobic alkyl chains of CTAB can interact with the hydrophobic regions of the metal-organic complex, further stabilizing the adsorption layer. This binding mechanism can help disperse and stabilize metal-organic complexes and modulate their properties.

[0137] Next, the metal organic complex solution and the MXene solution are compounded by mixing the metal organic complex combined with hexadecyltrimethylammonium bromide with the MXene solution, stirring and reacting to obtain a composite.

[0138] In the composite of metal-organic complexes and MXene solutions, surfactants play a key role. As mentioned earlier, surfactants act as a bridge between metal-organic complexes and MXene solutions, improving the interfacial affinity between metal-organic complexes and MXene and promoting more efficient reactions.

[0139] According to some embodiments of the present application, mixing the metal-organic complex solution with the MXene solution includes: dropwise adding the MXene solution to the stirred metal-organic complex solution; the MXene solution is added at a rate of 1-20 seconds per drop. The stirring state facilitates full contact between the MXene solution and the metal-organic complex solution, accelerating the reaction rate. By controlling the dropwise addition rate, the concentration of the solution in the reaction zone can be adjusted. Dropwise addition can form a relatively uniform reaction concentration field, which is conducive to the formation of well-dispersed crystals with uniform particle size.

[0140] Specifically, the MXene solution was dropped into the metal organic complex solution while stirring. The dropping speed of the MXene solution was 2 seconds per drop. After the dropwise addition was completed, stirring was continued for 24 hours. After the reaction was completed, the product was washed with methanol and vacuum dried at 60°C to obtain a complex of MXene and the metal organic complex.

[0141] Through the above reaction, a complex of MXene and metal organic complex was prepared, which is the precursor of M / MXene composite material and the prerequisite for finally obtaining M / MXene composite material.

[0142] Furthermore, the prepared composite of MXene and metal-organic complex is calcined. According to some embodiments of the present application, the composite of MXene and metal-organic complex is calcined to obtain an M / MXene composite material.

[0143] The calcination step converts the metal-organic complex precursor into a metal single atom or metal cluster complex. During calcination, a metal-nitrogen-carbon (MNC) structure can also be formed. At high temperatures, the metal-organic complex precursor undergoes decomposition or reduction reactions to generate metal single atoms or metal clusters. Simultaneously, at high temperatures, the volatile elements in the metal-organic complex precursor volatilize, forming porous carbon with a graphite phase structure. For example, when the metal-organic complex precursor is zeolitic imidazolate framework-8 (ZIF-8), at a pyrolysis carbonization temperature of 900°C, the volatile zinc is released from the ZIF-8 structure at high temperatures, ultimately resulting in a non-metallic nitrogen-doped graphitized porous carbon material. This material retains the regular rhombic dodecahedron morphology of ZIF-8, has a high nitrogen content, a high specific surface area, and a hierarchical pore structure.

[0144] Please refer to FIG8 , which is a schematic diagram of the reaction of preparing gas sensing materials according to one or more embodiments. x ) composite material as an example, in this case, the metal organic complex is nickel-based zeolite imidazolate framework-8 (Ni-ZIF-8). The metal organic complex Ni-ZIF-8 is first connected with the surfactant CTAB to form Ni-ZIF-8-CTAB. ZIF-8 is a metal organic framework material with a network porous crystal structure. CTAB wraps ZIF-8 and forms active sites on the surface of ZIF-8; then Ni-ZIF-8-CTAB binds to Ti3C2T through the active sites formed by CTAB. x Connect and complete the metal organic complex Ni-ZIF-8 and MXene Ti3C2T x Then calcined and pyrolyzed to form Ni-NC / Ti3C2T x Composite material: Ni-NC / Ti3C2T x The Ni in the composite material is bonded to four Ns to form a NiN4 structure, as shown in the black center area of ​​the upper structure in the figure. Then the NiN4 structure is bonded to the graphite structure formed by carbonization, as shown in the upper structure in the figure. Finally, the graphite structure is bonded to MXene (Ti3C2T x )complex.

[0145] According to some embodiments of the present application, the calcination temperature is 700-1000° C.; and / or the calcination time is 1-4 hours.

[0146] In one embodiment, the calcination temperature is 850-950°C.

[0147] Within this temperature and time range, the organic components in the metal-organic complex can undergo pyrolysis and carbonization to form porous carbon with a graphite phase structure. At the same time, some metal ions in the metal-organic complex skeleton volatilize at high temperatures to form defects and active sites.

[0148] Please refer to Figure 8. Taking the metal organic complex Ni-ZIF-8 as an example, when the calcination temperature is lower than 500℃, the sample maintains the structure and morphology of ZIF-8; when the temperature reaches 600℃, ZIF-8 begins to decompose and carbonize; as the temperature continues to rise above 750℃, the Zn in ZIF-8 2+ The ZIF-8 carbonizes into a porous carbon with a graphite phase structure. Under oxygen-free conditions, MXene loses very little mass within this temperature range, and its structure and composition hardly change.

[0149] Through the pyrolysis carbonization and metal ion volatilization that occur during the calcination process, the metal M is loaded on the surface of the MXene material in the form of a metal nitrogen-carbon compound, in which the carbon atoms exist in the form of graphite, and the nitrogen atoms bonded to the metal atoms are embedded in the graphite layer and bonded to the carbon atoms of the graphite layer.

[0150] According to some embodiments of the present application, calcining the composite includes: calcining the composite under a protective gas atmosphere, where the protective gas includes one or more of argon, hydrogen, and nitrogen.

[0151] The shielding gas is a stable gas whose primary function is to prevent oxidation during the calcination process. Argon is an inert gas with inactive chemical properties. Using it as a shielding gas can isolate the air and prevent oxidation. Nitrogen is stable and can also isolate the air and prevent oxidation. In addition to these functions, hydrogen also has a certain reducing effect, further preventing oxidation. These shielding gases can be a single gas or a mixture of two or more gases.

[0152] By introducing a protective gas during the calcination step, the oxidation reaction during the preparation of the gas sensing material can be reduced, which is beneficial to reducing the oxidation of MXene, protecting the activity of the active sites on the surface of the material, maintaining the normal progress of the reaction, and improving product quality.

[0153] The gas sensing material prepared by the above method has a confined structure at the interface between MXene and MNC, thereby forming a confinement effect between the substrates. It also has chemical sensitization and electronic sensitization sensing mechanisms, and enhances the sensing performance through the electron overflow effect.

[0154] According to some embodiments of the present application, the M / MXene composite material may also be doped, specifically by introducing doping elements at different process stages during the preparation of the M / MXene composite material.

[0155] According to some embodiments of the present application, during the calcination step, the composite may be calcined in a doping gas atmosphere to introduce doping elements. In one embodiment, the doping gas includes one or more of ammonia and hydrogen sulfide.

[0156] Unlike protective gases, doping gases can participate in the reaction while protecting the reaction. For example, ammonia can introduce nitrogen atoms into the metal atom ligands of the M / MXene composite material, and hydrogen sulfide can introduce sulfur atoms. That is, the metal atom M is coordinated and bonded with the nitrogen atom or the sulfur atom, replacing one or more of the four single atoms bonded to the metal atom M, thereby optimizing the sensing performance of the gas sensing material and enhancing the adaptability of the gas sensing material to different application requirements.

[0157] According to some embodiments of the present application, doping elements may also be introduced at the metal-organic complex stage. Specifically, the metal-organic complex is doped and modified before the metal-organic complex solution is mixed with the MXene solution.

[0158] Doped ligands can be those containing oxygen-containing elements such as oxygen and sulfur, such as -O, -OH, and -S. Due to the differences in chemical properties of non-metallic elements such as N, O, and S, when they form special configurations with metal atom centers, they can modulate the metal center's electrical properties, such as its spin state and d-band center, thereby regulating the binding energy between the active center and gas molecules, ultimately controlling the intrinsic activity of the gas sensing material. Other ligands can be halogen elements such as F, Cl, Br, and I. Due to the differences in electronegativity between the ligand elements, different ligands can modulate the electronic structure of the metal atom center to varying degrees, ultimately enabling the control of the gas sensing material's responsiveness and selectivity.

[0159] In some embodiments of the present application, before mixing the metal organic complex solution with the MXene solution, the steps include: providing a metal organic complex precursor and a doping precursor; mixing and reacting the metal organic complex precursor and the doping precursor to obtain a doped and modified metal organic complex.

[0160] A doping precursor is a compound used to introduce a doping element. It can be a standalone compound or a product derived from a metal-organic complex precursor through specific treatment or modification. The choice of doping precursor depends on the desired doping element and the specific application requirements of the material.

[0161] Doping precursors mainly include the following: one is metal salts, such as metal nitrates, metal chlorides, metal acetates, etc. The doping process can be achieved by reacting metal salts with metal organic complex precursors; the second is an organic compound, which contains the target doping element and can be a functional ligand, such as an organic acid, ketone, alcohol, etc. containing a specific functional group; the third is a gas source, such as the doping gas atmosphere in the calcination step mentioned above. The doping gas is introduced into the reaction system of the metal organic complex precursor to achieve the introduction of the doping element. In one embodiment of the present application, the doping precursor is thiourea, which is an organic sulfur-containing compound with a chemical formula of CH4N2S, which can provide sulfur as a doping element. The specific doping steps are detailed in the specific embodiments below.

[0162] By mixing a doping precursor and a metal organic complex precursor to obtain a doped modified metal organic complex, preferably a suitable doping precursor can effectively achieve the doping purpose and realize the doping of multiple elements, which is beneficial to purposefully modify the gas sensing material and broaden the application range of the gas sensing material.

[0163] The above embodiments, through doping modification, can adaptively design gas sensing materials for specific application scenarios based on specific gas types and response effects, which is conducive to purposefully modifying gas sensing materials and broadening the application range of gas sensing materials.

[0164] In some embodiments of the present application, a defect vacancy anchoring method can also be used to prepare a metal single-atom composite material. The lattice defects of the MXene carrier material are used to anchor the metal atom M, and the metal atom M coordinates or bonds with the surrounding carrier atoms (generally C atoms) to become part of the lattice structure. Due to the existence of chemical bonds and the influence of the nano-confinement effect, the doped metal atom M has a high stability. It may be that in the process of etching the MAX phase precursor to prepare MXene, some adjacent metal atoms in the MAX phase will fall off, thereby generating metal vacancy defects. This defect has high reduction activity and can spontaneously reduce and adsorb metal ions to fix single metal atoms without adding any reducing agent, so that the isolated metal atoms are stably present on the MXene carrier. In the metal single-atom composite material prepared by this method, the metal M is embedded in the structure of the MXene material in the form of a single atom.

[0165] Specifically, in one embodiment of the present application, titanium aluminum carbide (Ti3AlC2) is etched with lithium fluoride (LiF) and hydrochloric acid (HCl) solution to prepare Ti3C2T x During the formation of nanosheets, the Ti-Al bond is broken, causing the etching of adjacent Ti atoms, resulting in the formation of Ti single vacancies or vacancy clusters. This vacancy can adsorb Ni 2+The single-atom Ni-modified Ni-Ti3C2T x MXene composite materials. The specific preparation method is detailed in the specific examples below.

[0166] In some embodiments of the present application, a gas sensor is further provided, which includes any of the above-mentioned gas sensing materials; or includes a gas sensing material prepared using any of the above-mentioned methods.

[0167] Specifically, the M / MXene composite material is used as a gas sensing material. This material responds to the sensed gas based on changes in surface conductivity during gas adsorption and desorption. This material can achieve gas response in the absence of oxygen, resulting in a gas sensor that responds rapidly and with high sensitivity in the absence of oxygen. This gas sensor can respond to one or more gases including CO, NO2, NO, H2, CH4, H2S, ethylene, ethane, volatile organic compounds, and volatile electrolytes.

[0168] In order to make the technical problems, technical solutions and beneficial effects solved by the embodiments of the present application clearer, the following will be further described in detail with reference to the embodiments and drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its applications. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0169] 1. Preparation of gas sensing materials

[0170] Example 1

[0171] 1. Dissolve 0.96 g of zinc nitrate hexahydrate in 67 mL of methanol, then add 50 mg of nickel nitrate hexahydrate and stir evenly to obtain solution A.

[0172] 2. Dissolve 0.4 g of hexadecyltrimethylammonium bromide (CTAB) and 2.19 g of dimethylimidazole in 67 mL of methanol solution and stir until completely dissolved as solution B;

[0173] 3. Add solution B dropwise into solution A while stirring at a rate of 2 seconds per drop. Continue stirring for 2 hours after the addition is complete. Take 35 mL of the mixed solution as solution C.

[0174] 4. Dissolve 0.2 g of MXene in 5 mL of methanol solution and sonicate until completely dissolved as solution D;

[0175] 5. Solution D was added dropwise into solution C while stirring at a rate of 2 seconds per drop. After the addition was completed, stirring was continued for 24 hours. The product was washed with methanol and dried in a vacuum at 60°C. The product was placed in a tubular furnace and calcined at 900°C for 2 hours under a nitrogen atmosphere to obtain a (Ni-NC / MXene)-1 composite material, in which Ni was composited with the MXene material in the form of a single atom.

[0176] Example 2-3

[0177] Solution A was prepared differently from Example 1, replacing nickel nitrate hexahydrate with ferric nitrate hexahydrate and cobalt nitrate hexahydrate, respectively, to produce (Fe-NC / MXene)-2 and (Co-NC / MXene)-3 composite materials. Fe and Co were each composited with the MXene material in single-atom form. Specific reaction conditions are detailed in Table 1, which lists the type and form of the metal M for each example.

[0178] Example 4

[0179] The preparation of solution A was modified based on Example 1, except that the mass of nickel nitrate hexahydrate was replaced from 50 mg to 500 mg to obtain a (Ni-NC / MXene)-4 composite material. Ni was composited with the MXene material in the form of clusters. The specific reaction conditions are detailed in Table 1.

[0180] Example 5

[0181] 1. Add 1g of lithium fluoride (LiF) to 10mL of hydrochloric acid (HCl) solution and stir for 1h. Then add 1g of titanium aluminum carbide (Ti3AlC2) powder and heat in a water bath at 35℃ for 24h. The solution obtained after water bath is repeatedly centrifuged and washed with deionized water until the pH value is ≥5.5. The centrifugal speed is 9000rpm and the centrifugal time is 5min each time. Add 40mL of deionized water to the centrifuged product and ultrasonicate for 30min to obtain a suspension to obtain Ti3C2T x MXene solution, 8 mL of suspension was taken as solution A;

[0182] 2. Weigh 0.002 g of ferric chloride hexahydrate and add it to 50 mL of deionized water. Ultrasonicate for 30 minutes to obtain solution B.

[0183] 3. Solution B was slowly added dropwise to solution A at a rate of 2 seconds per drop. The mixture was stirred for 8 hours, and then 50 mL of acetone was added. The mixture was allowed to stand overnight, washed with acetone, and dried under vacuum at 60°C to obtain a (Ni / MXene)-5 composite material. Ni was composited with the MXene material in the form of a single atom.

[0184] Example 6

[0185] The preparation of solution A was modified based on Example 1. The difference was that 50 mg of nickel nitrate hexahydrate was replaced with 25 mg of nickel nitrate hexahydrate and 25 mg of ferric nitrate hexahydrate to prepare a (Ni-Fe-NC / MXene)-6 composite material. Ni and Fe were composited with the MXene material in the form of single atoms. The specific reaction conditions are detailed in Table 1.

[0186] Example 7

[0187] The preparation of solution A was modified based on Example 1. The difference was that 0.5 g of thiourea was added at the same time as nickel nitrate hexahydrate to obtain a (Ni-NSC / MXene)-7 composite material. Ni was composited with the MXene material in the form of a single atom. The specific reaction conditions are detailed in Table 1.

[0188] 2. Preparation of gas sensors

[0189] The gas sensing material was dispersed in ethanol at a concentration of 10 mg / L and treated with 40 kHz ultrasonic waves for 10 minutes to ensure uniform dispersion of the composite material. Gold electrodes were fabricated using micromachining, with a spacing of 800 μm between the positive and negative electrodes and 300 μm between adjacent electrodes. Five μL of the dispersion was dripped onto the interdigitated electrodes and dried under vacuum at 60°C for 1 hour to produce the gas sensor.

[0190] 3. Gas Sensing Performance Test

[0191] Please refer to Figure 9, which is a schematic diagram of a gas sensing performance test according to one or more embodiments. The gas sensor is placed in a test chamber, and the target gas is introduced by static gas distribution at room temperature. A constant operating voltage of 500mV is applied between the sensor electrodes, and the resistance change of the sensor in an inert gas and target gas environment is detected by an Agilent 4156C semiconductor parameter analyzer. Before the target gas is introduced, dry compressed nitrogen (MFC3) is used to purge the chamber to stabilize the baseline signal, and compressed nitrogen (MFC2) is used as a carrier gas to dilute the target gas, and the target gas is controlled by a mass flow controller (MFC1). The resistance difference between the sensor in dry nitrogen and the target gas is related to the resistance ratio in dry nitrogen (|R a -R g | / R a × 100%) is the response value of the device to the target gas, and the response and recovery time are defined by reaching 90% saturation of the response and recovery curves.

[0192] Table 1 Reaction parameters and performance parameters of each embodiment

[0193] Note: In Example 5, the metal M is embedded in the MXene in the form of a single atom. In the examples other than Example 5, the metal M is loaded on the surface of the MXene material in the form of a metal nitrogen-carbon compound. In the response value column, the gas concentration tested in Examples 1-7 is 20 ppm. The response time / recovery time column is the same as above.

[0194] Please refer to Figures 11 to 13. Figure 11 is a schematic diagram of the gas response of the gas sensing material Ni / MXene according to one or more embodiments, Figure 12 is a schematic diagram of the gas response of the gas sensing material Ni / MXene according to one or more embodiments, and Figure 13 is a schematic diagram of the gas response of the gas sensing material Ni / MXene according to one or more embodiments. Figure 11 tests the response of (Ni-NC / MXene)-1 to CO gas of different concentrations, Figure 12 tests the cyclic response performance of (Ni-NC / MXene)-1 to 1, 5, and 10 ppm CO gas, and Figure 13 tests the response of (Ni-NC / MXene)-1 to different gases with a concentration of 5 ppm. In Figures 11 and 12, the horizontal axis is the acquisition time and the vertical axis is the device sensitivity.

[0195] As shown in Figure 11, the response value of the (Ni-NC / MXene)-1 composite material sensor to 50ppm carbon monoxide reached 50.2%. The lowest detectable carbon monoxide concentration reached 1ppm, and the corresponding response value was 10.4%. As the carbon monoxide concentration increased, the sensor's response value to the gas also increased. When the carbon monoxide gas concentration was 5ppm, the response time was 40s and the recovery time was 120s, and the response and recovery speeds were relatively fast. Therefore, the (Ni-NC / MXene)-1 gas sensing material provided in this application has a high sensitivity for gas detection, a low detection limit, and a fast response recovery speed.

[0196] As can be seen from Figure 12, under three different gas concentrations, after five response-recovery cycles, the response value and response time of the (Ni-NC / MXene)-1 composite material sensor remain basically unchanged, indicating that the (Ni-NC / MXene)-1 gas sensing material provided in this application has good cyclic stability in gas response.

[0197] As shown in Figure 13, the (Ni-NC / MXene)-1 composite material responds to 5 ppm carbon monoxide, nitric oxide, nitrogen dioxide, methane, hydrogen, and ammonia. However, except for carbon monoxide, the response values ​​for other gases are very small. This shows that the (Ni-NC / MXene)-1 gas sensing material provided by this application exhibits good selectivity for carbon monoxide.

[0198] Please refer to Figures 14 to 16. Figure 14 is a schematic diagram showing the gas response of the Fe / MXene gas sensing material according to one or more embodiments. Figure 15 is a schematic diagram showing the gas response of the Co / MXene gas sensing material according to one or more embodiments. Figure 16 is a schematic diagram showing the gas response of the Ni / MXene gas sensing material according to one or more embodiments. The horizontal axis represents acquisition time, and the vertical axis represents device sensitivity.

[0199] In Figure 14, the response of the (Fe-NC / MXene)-2 composite material to different concentrations of NH3 gas was tested. The response value of the (Fe-NC / MXene)-2 composite material sensor to 20ppm ammonia reached 30.9%. The lowest detectable ammonia concentration reached 1ppm, and the corresponding response value was 25.6%. As the ammonia concentration increases, the response value of the sensor to the gas also increases. When the ammonia gas concentration is 20ppm, the response time is 80s and the recovery time is 100s. Therefore, the (Fe-NC / MXene)-2 gas sensing material provided in this application has a high sensitivity for gas detection, a low detection limit, and a fast response recovery speed.

[0200] Figure 15 shows the response of the (Co-NC / MXene)-3 composite material to 20 ppm NO₂ gas. The (Co-NC / MXene)-3 composite sensor exhibited a 6.4% response to 20 ppm nitrogen dioxide, a response time of 60 seconds, and a recovery time of 80 seconds. Both the response value and response time remained essentially unchanged over two cycles. Therefore, the (Co-NC / MXene)-3 gas sensing material provided herein can be applied to nitrogen dioxide gas detection.

[0201] Figure 16 shows the response of the (Ni-NC / MXene)-4 composite material to 20 ppm CO gas. The (Ni-NC / MXene)-4 composite sensor exhibited a 5.5% response to 20 ppm CO, a 40s response time, and a 90s recovery time. Both the response value and response time remained essentially unchanged over five cycles. Therefore, the (Ni-NC / MXene)-4 composite material provided herein can be used for carbon monoxide gas detection and exhibits good gas response cyclic stability.

[0202] Refer to Table 1. Examples 1-3 produced (Ni-NC / MXene)-1, (Fe-NC / MXene)-2, and (Co-NC / MXene)-3 composite materials. These three composites contain different metals (M), and therefore respond to different gases: CO, NH₃, and NO₂. This indicates that different metals bind differently to gas molecules. Therefore, the selectivity of gas sensing can be regulated by selecting different metal elements.

[0203] Furthermore, compared to the (Fe-NC / MXene)-2 and (Co-NC / MXene)-3 composites, the (Ni-NC / MXene)-1 composite material exhibited a higher response value and a shorter response time at the same concentration of the detected gas, indicating that the nickel-based gas sensing material exhibited the highest sensitivity of the three. Therefore, the sensitivity of gas sensing can be tuned by selecting different metal elements.

[0204] Examples 1 and 4 prepared (Ni-NC / MXene)-1 and (Ni-NC / MXene)-4 composite materials, in which metallic Ni was composited with MXene materials in the form of single atoms and clusters, respectively. It can be seen that the response value of (Ni-NC / MXene)-1 to 20 ppm CO is 43.1%, while the response value of (Ni-NC / MXene)-4 to 20 ppm CO is only 5.5%. This shows that even though (Ni-NC / MXene)-4 has more Ni atomic active sites, the clustered Ni atoms still reduce the sensing performance.

[0205] Example 1 and Example 5 prepared (Ni-NC / MXene)-1 and (Ni / MXene)-5 composite materials, in which metal Ni single atoms were embedded in MXene in the form of single atoms or loaded on the surface of MXene materials in the form of metal nitrogen-carbon compounds. Please refer to Figure 10, which is a schematic diagram of the gas response of the gas sensing material Ni / MXene according to one or more embodiments. The horizontal axis is the acquisition time and the vertical axis is the device sensitivity. It can be seen that the response value of (Ni-NC / MXene)-1 to 20ppm CO is 43.1%, while the response value of (Ni / MXene)-5 to 20ppm CO is only 0.6%. It shows that the metal nitrogen-carbon compound form optimizes the sensing performance of the gas sensing material.

[0206] In Example 1 and Example 6, (Ni-NC / MXene)-1 and (Ni-Fe-NC / MXene)-6 composite materials were prepared. These two composite materials are metal single-atom composite materials and metal double-atom composite materials, respectively. It can be seen that the response value of (Ni-NC / MXene)-1 to 20ppm CO is 43.1%, while the response value of (Ni-Fe-NC / MXene)-6 to 20ppm CO is 37.5%; at the same time, the response time of (Ni-Fe-NC / MXene)-6 is also longer, but the recovery time is shorter. This shows that after a part of the Ni atoms in the composite material are replaced by Fe atoms, the sensing performance for CO is not improved. The reason is that Ni atoms have a good selective response effect to CO, while Fe atoms are not as responsive to CO as Ni atoms.

[0207] Examples 1 and 7 produced (Ni-NC / MXene)-1 and (Ni-NSC / MXene)-7 composite materials, with the (Ni-NSC / MXene)-7 composite material doped with sulfur. The response of (Ni-NC / MXene)-1 to 20 ppm CO was 43.1%, while that of (Ni-NSC / MXene)-7 was 45.6%. Furthermore, the recovery time of (Ni-NSC / MXene)-7 was shortened. This suggests that NiN3S active sites are more reactive than NiN4, and therefore, gas sensing materials can be modified by adding doping elements.

[0208] The above examples demonstrate that the gas sensing materials provided herein exhibit excellent gas sensitivity and selectivity. Furthermore, these gas sensing materials were tested in an oxygen-free environment at room temperature. Compared to existing materials that require high temperatures and the presence of oxygen for gas response, these materials offer more moderate conditions and a wider range of applications.

[0209] In some embodiments of the present application, the gas sensor provided in the present application can be used to detect gas inside a battery. That is, the present application provides a battery comprising the gas sensor of the above embodiment.

[0210] Please refer to Figure 17, which is a schematic diagram of an exploded structure of a battery according to one or more embodiments. Battery 100 includes a housing 10 and battery cells 20, with battery cells 20 housed within housing 10. Housing 10 provides storage space for battery cells 20 and can have various structures. In some embodiments, housing 10 can include a first portion 11 and a second portion 12, which overlap each other and together define a storage space for battery cells 20. Second portion 12 can be a hollow structure with one end open. First portion 11 can be a plate-like structure, overlapping the open side of second portion 12, so that the first and second portions 11 and 12 together define a storage space. Alternatively, first portion 11 and second portion 12 can each be a hollow structure with one end open, with the open side of first portion 11 overlapping the open side of second portion 12. Housing 10 formed by first portion 11 and second portion 12 can have various shapes, such as a cylinder or a rectangular parallelepiped. The gas sensor may be installed inside the box 10 .

[0211] In the battery 100, there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery cell 20 may be housed within the housing 10. Alternatively, the battery 100 may be constructed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid connection to form a battery module, which is then connected in series, in parallel, or in a hybrid connection to form a complete battery module, and then housed within the housing 10. The battery 100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0212] Each battery cell 20 may be a secondary battery or a primary battery, and may also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0213] Please refer to Figure 18, which is a schematic diagram of the exploded structure of a battery cell according to one or more embodiments. A battery cell 20 is the smallest unit that makes up a battery. As shown in Figure 18, a battery cell 20 includes an end cap 21, a housing 22, an electrode assembly 23, and other functional components.

[0214] The end cap 21 refers to a component that covers the opening of the shell 22 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 21 can be adapted to the shape of the shell 22 to match the shell 22. In one embodiment, the end cap 21 can be made of a material with a certain hardness and strength (such as an aluminum alloy). In this way, the end cap 21 is not easily deformed when squeezed or collided, so that the battery cell 20 can have a higher structural strength and improved safety performance. Functional components such as electrode terminals 21a can be provided on the end cap 21. The electrode terminal 21a can be used to electrically connect to the electrode assembly 23 for outputting or inputting electrical energy of the battery cell 20. In some embodiments, the end cap 21 can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold. The material of the end cap 21 can also be various, including but not limited to copper, iron, aluminum, stainless steel, aluminum alloy, and plastic. In some embodiments, an insulating member may be provided inside the end cap 21 to isolate the electrical connection components in the housing 22 from the end cap 21 to reduce the risk of short circuit. For example, the insulating member may be made of plastic, rubber, or the like.

[0215] The housing 22 is a component that cooperates with the end cap 21 to form the internal environment of the battery cell 20, wherein the formed internal environment can be used to accommodate the electrode assembly 23, electrolyte, and other components. The housing 22 and the end cap 21 can be independent components. An opening can be provided in the housing 22, and the end cap 21 is closed at the opening to form the internal environment of the battery cell 20. The end cap 21 and the housing 22 can also be integrated. Specifically, the end cap 21 and the housing 22 can form a common connection surface before other components are inserted into the housing. When the interior of the housing 22 needs to be encapsulated, the end cap 21 is closed to the housing 22. The housing 22 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the housing 22 can be determined according to the specific shape and size of the electrode assembly 23. The housing 22 can be made of various materials, including but not limited to copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0216] The electrode assembly 23 is a component in the battery cell 100 where electrochemical reactions occur. One or more electrode assemblies 23 may be contained in the housing 22. The electrode assembly 23 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The parts of the positive and negative electrode sheets with active materials constitute the main body of the electrode assembly, and the parts of the positive and negative electrode sheets without active materials each constitute a tab 23a. The positive and negative electrode tabs may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery, the positive active material and the negative active material react with the electrolyte, and the tabs 23a connect the electrode terminals to form a current loop.

[0217] In one embodiment, the positive electrode sheet includes a current collector and a positive active layer disposed on the current collector.

[0218] The positive electrode active layer includes a positive electrode active material, and the positive electrode active material may include at least one of the following materials: lithium-containing phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and its modified compounds. Examples of olivine-structured lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0219] In one embodiment, the positive electrode active layer also includes a conductive agent, thereby giving the electrode conductivity. The positive electrode conductive material may include any conductive material as long as it does not cause chemical changes. Non-limiting examples of positive electrode conductive materials include carbon-based materials (e.g., natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, etc.), metal-based materials (e.g., metal powder, metal fiber, etc., including, for example, copper, nickel, aluminum, silver, etc.), conductive polymers (e.g., polyphenylene derivatives) and mixtures thereof. In one embodiment, the conductive agent includes one or more of conductive carbon black, conductive graphite, carbon fiber, carbon nanotubes, graphene, Ketjen black and acetylene black.

[0220] In one embodiment, the positive electrode active layer further includes a binder to improve the adhesion stability of the active layer and reduce the probability of powder loss. The binder can be one or more of styrene-butadiene rubber (SBR), water-based acrylic resin, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA), polyacrylic acid (PAA), carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), and polyvinyl butyral (PVB). In one embodiment, the binder includes one or more of polyvinylidene fluoride, polytetrafluoroethylene, acrylate, and polyurethane.

[0221] In one embodiment, the positive electrode active layer further includes other optional additives, which may be thickening and dispersing agents (such as sodium carboxymethyl cellulose CMC-Na) and PTC thermistor materials.

[0222] In one embodiment, the negative electrode sheet includes a negative electrode current collector and a negative electrode active layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode active layer includes a negative electrode active material. In this embodiment, the battery cell is an ion battery. During the charge and discharge process of the battery, active ions (such as Li + 、Na + ) is embedded / deintercalated in the negative electrode active material.

[0223] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active layer may be disposed on either or both of the two facing surfaces of the negative electrode current collector.

[0224] In one embodiment, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer base layer and a metal layer formed on at least one surface of the polymer base material. The composite current collector may be obtained by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer base material (such as a base material of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0225] The negative electrode active layer includes a negative electrode active material, which includes but is not limited to carbon-based negative electrode materials, silicon-based negative electrode materials, tin-based negative electrode materials, lithium titanate negative electrode materials, metallic lithium negative electrode materials, etc.; specifically includes but is not limited to graphite materials, silicon-carbon materials, graphite-silicon oxide materials, nano-silicon materials, silicon oxide materials and tin-based materials; more specifically includes natural graphite, artificial graphite, mesophase microcarbon beads (abbreviated as MCMB), hard carbon, soft carbon, silicon, silicon-carbon composites, Li-Sn alloys, Li-Sn-O alloys, Sn, SnO, SnO2, spinel structured lithiated TiO2-Li4Ti5O 12 , one or more of Li-Al alloys.

[0226] In one embodiment, the negative electrode plate includes a negative electrode current collector and a carbonaceous coating provided on at least one surface of the negative electrode current collector. In this embodiment, the battery cell is a metal battery, and during the charge and discharge process of the battery, active ions are deposited / stripped at the negative electrode plate. The metal battery can be an alkali metal battery, such as a lithium metal battery, a sodium metal battery, a potassium metal battery, a zinc metal battery, or an aluminum metal battery. This type of battery can also be called a "negative electrode-free battery". During the charging process, the active ions (such as Na + ) is deposited onto the negative electrode current collector to form sodium metal. The provision of a carbon-containing coating facilitates more uniform metal deposition. The carbon-containing material includes one or more of conductive carbon, graphite, hard carbon, and carbon nanotubes.

[0227] In other embodiments, a conductive film layer may be deposited on the negative electrode current collector. Examples include alloy materials, titanium-based materials, active metals (e.g., sodium metal), carbon-based materials deposited with metals, composite materials containing metals, and alloy materials containing metals. Such alloy materials include, but are not limited to, sodium-tin alloys, sodium-germanium alloys, and sodium-antimony alloys. Such titanium-based materials include, but are not limited to, titanium dioxide, titanates, and titanium phosphates.

[0228] In some embodiments, the negative electrode active layer may further include a binder, a conductive agent, and other optional additives. As an example, the conductive agent may be one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, Super P (SP), graphene, and carbon nanofibers. As an example, the binder may be one or more of styrene-butadiene rubber (SBR), water-based acrylic resin, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA), polyacrylic acid (PAA), carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), and polyvinyl butyral (PVB). As an example, other optional additives may be thickening and dispersing agents (e.g., sodium carboxymethyl cellulose CMC-Na) and PTC thermistor materials.

[0229] In some embodiments, the material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0230] In one embodiment, the electrolyte includes one or more of carbonate solvents and ether solvents.

[0231] Carbonates are generally small molecule cyclic or chain carbonates; including but not limited to one or more of ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, methylpropyl carbonate, dipropyl carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and fluorocarbonates; and may also be at least one ester solvent selected from γ-butyrolactone, dimethyl sulfite, ethyl acetate, methyl acetate, methyl butyrate, ethyl butyrate, methyl propionate, ethyl propionate, propyl acetate, and fluorocarboxylic acid esters.

[0232] Ether solvents include, but are not limited to, one or more of dimethyl ether, diethyl ether, tetrahydrofuran, methyltetrahydrofuran, ethylene oxide, 1,3-dioxolane, fluoroether, DME (ethylene glycol dimethyl ether), DEE (ethylene glycol diethyl ether), DEGDME (diethylene glycol dimethyl ether), TRGDME (triethylene glycol dimethyl ether), TEGDME (tetraethylene glycol dimethyl ether), dipropyl ether and dibutyl ether.

[0233] In other embodiments, the electrolyte may also include any one or a mixture of several of an amine solvent, a sulfone solvent, and a nitrile solvent. The amine solvent includes at least one of N-methylacetamide, N-methylformamide, dimethylformamide, and diethylformamide. The sulfone solvent includes at least one of dimethyl sulfoxide, cyclopentane sulfone, diphenyl sulfoxide, thionyl chloride, and dipropyl sulfone. The nitrile solvent includes at least one of acetonitrile, succinonitrile, adiponitrile, and glutaronitrile. The electrolyte is preferably a high-voltage resistant electrolyte, which has reduced acidity under high voltage, can facilitate the transmission of active ions, significantly reduce side reactions on the electrode surface, and improve battery stability.

[0234] In some embodiments, the electrolyte further includes an electrolyte salt, which can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0235] In some embodiments, the electrolyte further includes additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, and additives that improve battery high or low temperature performance.

[0236] The battery disclosed in the embodiments of the present application can be used in various energy storage systems that use batteries as power sources or use batteries as energy storage elements. That is, the present application provides an electric device, and the electric device includes the battery of the above embodiment. In some embodiments, the electric device of the present application can be used for, but not limited to, laptop computers, pen-input computers, mobile computers, e-book players, portable phones, portable fax machines, portable copiers, portable printers, head-mounted stereo headphones, video recorders, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, cars, motorcycles, power-assisted bicycles, bicycles, ships, spacecraft, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries and lithium-ion capacitors, etc.

[0237] Electrical equipment can choose battery cells, battery modules or battery packs according to its usage requirements.

[0238] Please refer to Figure 19, which is a schematic structural diagram of a vehicle according to one or more embodiments. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 can be provided at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can serve as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0239] In some embodiments of the present application, battery 100 can serve not only as an operating power source for vehicle 1000, but also as a driving power source for vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for vehicle 1000. In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0240] The above description is only an implementation method of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A battery, wherein: Including gas sensors; The gas sensor comprises a gas sensing material, wherein the gas sensing material comprises an M / MXene composite material, wherein the M / MXene composite material comprises metal (M) single atoms and MXene material; and / or The M / MXene composite material includes metal (M) clusters and MXene materials.

2. The battery according to claim 1, wherein The M / MXene composite material includes a metal (M) nitrogen-carbon compound, and the metal nitrogen-carbon compound is loaded on the surface of the MXene material.

3. The battery according to claim 2, wherein Each metal atom M in the metal nitrogen-carbon compound is bonded to four nitrogen atoms respectively.

4. The battery according to claim 3, wherein The metal nitrogen-carbon compound includes a graphite structure, the nitrogen atom bonded to the metal atom M is embedded in the graphite structure and bonded to the carbon atom of the graphite structure, and the graphite structure is combined with the surface of the MXene material.

5. The battery according to any one of claims 2 to 4, wherein: The metal nitrogen-carbon compound is doped with an X element, wherein X includes one or more of sulfur, phosphorus and boron.

6. The battery according to claim 5, wherein Each metal atom M in the metal nitrogen-carbon compound is bonded to four nitrogen atoms respectively, and the doped X element replaces one or more of the four nitrogen atoms bonded to the metal atom M.

7. The battery according to claim 1, wherein The metal (M) single atom in the M / MXene composite material is embedded in the structure of the MXene material.

8. The battery according to any one of claims 1 to 7, wherein: The metal M includes one or more of Fe, Co, Ni, Mn, Cu, Zn, Cr, Pd, Pt, Au, Ag, Ir, and Ru.

9. The battery according to any one of claims 1 to 8, wherein: The metal M includes one or more of Fe, Co, and Ni.

10. The battery according to any one of claims 1 to 9, wherein: The size of the metal (M) single atom in the M / MXene composite material is less than 1 nm; and / or The size of the metal (M) clusters in the M / MXene composite material is 1-50 nm.

11. The battery according to any one of claims 1 to 10, wherein: The size of the metal (M) single atom in the M / MXene composite material is less than 0.5 nm; and / or The size of the metal (M) clusters in the M / MXene composite material is 10-30 nm.

12. The battery according to any one of claims 1 to 11, wherein: Based on the total number of atoms of the M / MXene composite material, the atomic content (at%) of the metal M element is less than or equal to 15%.

13. The battery according to any one of claims 1 to 12, wherein: Based on the total number of atoms of the M / MXene composite material, the atomic content (at%) of the metal M element is less than or equal to 10%.

14. The battery according to any one of claims 1 to 13, wherein: Based on the total number of atoms of the M / MXene composite material, the atomic content (at%) of the metal M element is less than or equal to 5%.

15. The battery according to any one of claims 1 to 14, wherein The MXene material includes M' n+1 X' n T x , where M' is an early transition metal element, X' is carbon or nitrogen, T x OH - , O 2- 、F - Any one of the groups.

16. The battery according to any one of claims 1 to 15, wherein: The response gas of the gas sensing material includes one or more of CO, NO2, NO, H2, CH4, H2S, ethylene, ethane, volatile organic compounds, and volatile electrolytes.

17. The battery according to claim 16, wherein: The volatile organic compound includes at least one of methanol, formaldehyde, toluene, styrene, phenol and benzene.

18. The battery according to claim 16 or 17, wherein: The volatile electrolyte includes at least one of a polyether electrolyte and a polyester electrolyte.

19. The battery according to any one of claims 1 to 18, wherein: The gas sensing material has a sensing response to gas within the range of -55°C to 65°C.

20. A gas sensing material, wherein: The gas sensing material comprises an M / MXene composite material, wherein the M / MXene composite material comprises metal (M) single atoms and MXene material; and / or The M / MXene composite material includes metal (M) clusters and MXene materials.

21. A method for preparing a gas sensing material, wherein: include: Providing a composite of MXene and a metal organic complex, wherein the metal organic complex is a complex of a metal M and an organic ligand; The composite is calcined to obtain an M / MXene composite material, wherein the M / MXene composite material includes metal (M) single atoms and MXene materials; and / or the M / MXene composite material includes metal (M) clusters and MXene materials.

22. The method for preparing a gas sensing material according to claim 21, wherein: The calcining of the composite comprises: The calcination temperature is 700-1000°C; and / or The calcination time is 1-4h.

23. The method for preparing a gas sensing material according to claim 21 or 22, wherein: The calcining of the composite comprises: calcining the composite under a protective gas atmosphere, wherein the protective gas comprises one or more of argon, hydrogen and nitrogen; and / or The composite is calcined in a doping gas atmosphere, wherein the doping gas includes one or more of ammonia and hydrogen sulfide.

24. The method for preparing a gas sensing material according to any one of claims 21 to 23, wherein: The composite of MXene and metal organic complex is provided including: The metal organic complex solution and the MXene solution are mixed and stirred for reaction to obtain the composite.

25. The method for preparing a gas sensing material according to claim 24, wherein: The mixing of the metal organic complex solution and the MXene solution comprises: Adding the MXene solution dropwise into the metal organic complex solution in a stirring state; The dropping speed of the MXene solution is 1-20 seconds per drop.

26. The method for preparing a gas sensing material according to claim 24 or 25, wherein: The step of mixing the metal organic complex solution with the MXene solution comprises: combining the metal organic complex with a surfactant; and / or The MXene solution is combined with a surfactant.

27. The method for preparing a gas sensing material according to claim 26, wherein: The surfactant includes cetyltrimethylammonium bromide.

28. The method for preparing a gas sensing material according to claim 27, wherein: The combining of the metal organic complex and the surfactant comprises: Providing metal organic complex precursors and hexadecyltrimethylammonium bromide; The metal organic complex precursor and hexadecyltrimethylammonium bromide are mixed and reacted to obtain the metal organic complex combined with hexadecyltrimethylammonium bromide.

29. The method for preparing a gas sensing material according to any one of claims 24 to 28, wherein: The step of mixing the metal organic complex solution with the MXene solution comprises: Providing metal organic complex precursors and doping precursors; The metal organic complex precursor and the doping precursor are mixed and reacted to obtain a metal organic complex with a doping element.

30. A method for preparing a gas sensing material, wherein: include: Etching the MXene material precursor to obtain a MXene material with defect vacancies; The metal organic complex is reacted with the MXene material with defect vacancies to obtain an M / MXene composite material, wherein the M / MXene composite material includes metal (M) single atoms and MXene material; and / or the M / MXene composite material includes metal (M) clusters and MXene material.

31. A gas sensor, wherein: The method comprises the gas sensing material as claimed in claim 20; or comprises the gas sensing material prepared by the method as claimed in any one of claims 21 to 30.

32. An electrical device, wherein: A battery comprising any one of claims 1 to 19.

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