Gas sensing material and preparation method thereof, sensor, battery and electric equipment

Abstract

The invention discloses a gas sensing material and a preparation method thereof, a sensor, a battery and electric equipment. Wherein the gas sensing material comprises a palladium-carbon nanotube composite material, and response gas of the palladium-carbon nanotube composite material under the anaerobic condition comprises at least one of hydrogen, carbon monoxide and ammonia gas. According to the gas sensing material, the gas sensing effect is achieved through the change of the surface resistance of the gas sensing material when palladium metal interacts with target gas, no oxygen participates in the reaction process, and meanwhile charge transfer can be accelerated through the special structure and the semiconductor property of the carbon nanotubes. Through the above mode, the application can realize rapid response to the target gas under an anaerobic condition, and can realize detection of gas produced in the battery.

Description

Technical Field

[0001] The present application relates to the field of new energy technologies, and particularly to gas sensing materials and their preparation methods, sensors, batteries, and electrical equipment. Background Art

[0002] With the continuous exacerbation of global energy and environmental problems, new energy, as one of the fields of sustainable development, is developing rapidly. Batteries are being applied more and more widely as a new energy source. Among them, the problem of gas production in batteries has always been a concern. The gases generated by batteries are prone to cause safety problems such as explosions and fires. By detecting the gas conditions inside the battery, early warnings can be given in a timely manner. Most of the sensing principles of existing gas sensors rely on oxygen and have a relatively small response speed, so there are limitations in the application environment and response effect. The above statements are only used to provide background technical information related to the present application, and do not necessarily constitute prior art. Summary of the Invention

[0003] The main technical problem to be solved by the present application is to provide a gas sensing material and its preparation method, a sensor, a battery, and electrical equipment, which have the advantage of being able to perform rapid gas sensing under anaerobic conditions.

[0004] To solve the above technical problem, a technical solution adopted by the present application is: to provide a gas sensing material, including a palladium-carbon nanotube composite material, and the response gases of the palladium-carbon nanotube composite material under anaerobic conditions include at least one of hydrogen, carbon monoxide, and ammonia. This composite material combines the gas sensitivity of palladium metal, the high conductivity, and high stability of carbon nanotubes, can effectively adsorb gas molecules, and at the same time can accelerate the diffusion rate of gases on the sensing material, and accelerate the charge transfer caused by gas adsorption, so that the composite material can perform rapid gas sensing under anaerobic conditions.

[0005] In one embodiment, the composite material further includes a second metal. Optionally, the second metal includes one or more of copper, silver, gold, and nickel. By introducing the second metal, the synergistic effect of two or more metals can improve the gas response value.

[0006] In one embodiment, the second metal forms an alloy with palladium or the second metal is a metal simple substance. By forming an alloy with the above metals or attaching the metal simple substance of the second metal to the surface of the carbon nanotubes, the gas response value can be improved.

[0007] In one embodiment, based on the total mass of the composite material, the content of palladium is greater than 0 and less than or equal to 50%, and optionally, greater than 1% and less than or equal to 20%. By controlling the content of palladium within the above range, the gas response value can be improved.

[0008] In one embodiment, the carbon nanotubes include single-walled carbon nanotubes and / or multi-walled carbon nanotubes. Optionally, the carbon nanotubes further include inorganic non-metallic elements. More optionally, the inorganic non-metallic elements include at least one of N, S, B, P, and F. By selecting or doping the carbon nanotubes with non-metals, the gas response value can be improved.

[0009] In one embodiment, the response gases of the gas sensing material include at least one of hydrogen, carbon monoxide, and ammonia. Palladium can react specifically with the above gases, expanding the applicable range. At the same time, it has a strong specific reaction to hydrogen. Therefore, the anti-interference performance of the gas sensing material can be improved.

[0010] To solve the above technical problems, another technical solution adopted in this application is: to provide a preparation method of a gas sensing material, including: mixing a palladium precursor and a carbon nanotube solution to obtain a mixed solution; drying the mixed solution to obtain a powder; calcining the powder to obtain a palladium-carbon nanotube composite material. The response gases of the palladium-carbon nanotube composite material under anaerobic conditions include at least one of hydrogen, carbon monoxide, and ammonia.

[0011] The palladium-carbon nanotube composite material combines the gas sensitivity of palladium metal, the high conductivity, and the high stability of carbon nanotubes. It can effectively adsorb gas molecules, and at the same time, it can accelerate the diffusion rate of gases on the sensing material, accelerating the charge transfer caused by gas adsorption, enabling the composite material to perform rapid gas sensing response under anaerobic conditions.

[0012] In one embodiment, in the step of mixing the palladium precursor and the carbon nanotubes, the mixed solution further includes a second metal precursor. The second metal precursor forms a palladium alloy or a second metal simple substance with palladium metal.

[0013] In one embodiment, in the step of mixing the palladium precursor and the carbon nanotubes, the mixed solution further includes a linker, and the linker can promote the binding of palladium metal and / or the second metal to the carbon nanotubes.

[0014] In one embodiment, the linker includes any one of dopamine and cetyltrimethylammonium bromide. By defining the linker, the binding of palladium metal and carbon nanotubes can be promoted.

[0015] To solve the above technical problems, another technical solution adopted in this application is: to provide a gas sensor, the sensor includes the gas sensing material of any one of the above; or includes the gas sensing material prepared by the method of any one of the above. Through the above settings, high-sensitivity response to target gases in an anaerobic environment can be achieved.

[0016] To solve the above technical problems, another technical solution adopted by this application is: to provide a battery, which includes the gas sensor according to any one of the above. Through the above arrangement, it is possible to achieve a high-sensitivity response to the target gas and a rapid recovery in an oxygen-free environment.

[0017] To solve the above technical problems, another technical solution adopted by this application is: to provide an electrical device, which includes the above battery. The electrical device has at least the same advantages as the battery.

[0018] The above description is only an overview of the technical solution of this application. In order to be able to understand the technical means of this application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of this application more obvious and understandable, the following specifically illustrates the specific implementation manners of this application. Brief Description of the Drawings

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to these drawings.

[0020] Figure 1 It is a transmission electron microscope (TEM) image of a gas sensing material according to one or more embodiments;

[0021] Figure 2 It is a schematic diagram of the gas response of a gas sensing material according to one or more embodiments;

[0022] Figure 3 It is a scanning electron microscope (SEM) image of a gas sensing material according to one or more embodiments;

[0023] Figure 4 It is a schematic diagram of the gas sensing performance test of a gas sensing material according to one or more embodiments;

[0024] Figure 5 It is a schematic diagram of the gas response of a gas sensing material according to one or more embodiments;

[0025] Figure 6 It is a schematic diagram of the gas response of a gas sensing material according to one or more embodiments;

[0026] Figure 7 It is a schematic diagram of the gas response of a gas sensing material according to one or more embodiments;

[0027] Figure 8 It is a schematic diagram of the gas response of a gas sensing material according to one or more embodiments;

[0028] Figure 9 Schematic diagram of the gas response of a gas sensing material according to one or more embodiments;

[0029] Figure 10 Schematic diagram of the gas response of a gas sensing material according to one or more embodiments;

[0030] Figure 11 Schematic diagram of the exploded structure of a battery according to one or more embodiments;

[0031] Figure 12 Schematic diagram of the exploded structure of a battery cell according to one or more embodiments;

[0032] Figure 13 Schematic diagram of the structure of a vehicle according to one or more embodiments.

[0033] In the drawings:

[0034] 1000, vehicle; 300, motor; 200, controller; 100, battery; 10, box body; 11, first part; 12, second part; 20, battery cell; 21, end cover; 21a, electrode terminal; 22, housing; 23, electrode assembly. Detailed implementation manners

[0035] To make the objectives, technical solutions and effects of this application clearer and more definite, the following will describe in detail the embodiments of the technical solutions of this application with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solutions of this application more clearly, so they are only examples and cannot be used to limit the protection scope of this application.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field 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 accompanying drawing descriptions are intended to cover non-exclusive inclusion.

[0037] In the description of the embodiments of this application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of this application, the term "plurality" means more than two (including two). Similarly, "multiple groups" means more than two groups (including two groups), and "multiple pieces" means more than two pieces (including two pieces), unless otherwise specifically defined.

[0038] References to "embodiments" in this specification mean that specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment each time, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will understand explicitly and implicitly that the embodiments described herein can be combined with other embodiments.

[0039] In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this text generally represents an "or" relationship between the associated objects before and after.

[0040] Quantities, ratios, and other numerical values are presented in a range format in this text. It should be understood that such range formats are for convenience and brevity, and should be understood flexibly, including not only the numerical values explicitly specified as range limits, but also all individual numerical values or sub-ranges covered by the said range, as if each numerical value and sub-range were explicitly specified.

[0041] If there is no special indication, all steps of the present application can be carried out sequentially, randomly, or in parallel, and preferably sequentially. For example, the method includes steps (a) and (b), which means that the method can include steps (a) and (b) carried out sequentially, or steps (b) and (a) carried out sequentially, or steps (a) and (b) carried out in parallel simultaneously. For example, it is mentioned that the method may further include step (c), which means that step (c) can be added to the method in any order. For example, the method can include steps (a), (b), and (c), or steps (a), (c), and (b), or steps (c), (a), and (b), etc.

[0042] Under the new round of technological revolution, the new energy industry shows a rapid development trend. As an important part of the new energy industry, the power battery industry has also developed rapidly accordingly. Currently, power batteries are widely used in electric vehicles, energy storage systems, and renewable energy fields. With the growing demand for clean energy and sustainable development, the application of batteries in the new energy field will continue to expand and promote the further development of energy transformation. With the new development of power batteries in China, power batteries will surely achieve improvements in many aspects. From a technical perspective, during the improvement process, "high safety", "high efficiency", "long life", and "low cost" will be the core solutions and pursuit goals for the development of power battery technology.

[0043] During the charge and discharge process of the battery, some side reactions will generate gases. If the gases generated by the battery are not discharged in time, it will lead to an increase in the internal pressure of the battery, exceeding the normal level. Excessive internal pressure will have a negative impact on the performance and appearance of the battery. For example, in severe cases, it will have a destructive impact on the performance and appearance of the battery, such as leakage, bottom swelling, an increase in the internal resistance of the battery, a shorter discharge time, and a shorter cycle life. In addition, there are some abnormal operations during the use of the battery, including overcharging, over-discharging, internal faults, etc. In this case, the chemical reactions inside the battery may get out of control, accompanied by a violent release of gases, and even trigger thermal runaway of the battery. Thermal runaway of the battery refers to a chain reaction phenomenon triggered by various inducements. The large amount of heat and harmful gases emitted during thermal runaway will cause the battery to catch fire and explode.

[0044] In order to monitor the gas production of the battery in a timely manner, a gas sensor can be installed inside the battery. Different types of characteristic gases are generated in different batteries. The composition of the gas sensing material can be adjusted to make it selective to different types of characteristic gases, so as to achieve adaptive applications for different batteries. However, existing gas sensors have defects in the detection of battery gas production. In application environments such as battery packs, they are usually in a low-oxygen or oxygen-free state, making electrochemical sensors and resistive sensors that rely on oxygen unable to work properly.

[0045] Palladium metal has been proven to have a specific response behavior to hydrogen, and this response behavior does not depend on oxygen. However, the adsorption rate of pure palladium to hydrogen is slow, and there are problems such as low sensitivity and slow response speed in gas sensing.

[0046] Based on the above considerations, this application designs a gas sensing material. This gas sensing material is a chemiresistive sensing material, which relies on the change in the surface resistance of the sensor when the gas-sensitive material palladium metal interacts with the target gas to achieve the detection purpose. There is no oxygen involved in the reaction process. At the same time, carbon nanotubes with semiconductor properties are used as the substrate of the gas-sensitive material palladium metal, enabling the above gas sensing material to respond to hydrogen in an oxygen-free environment, with high sensitivity and fast response speed.

[0047] According to some embodiments of this application, this application discloses a gas sensing material, which includes a palladium-carbon nanotube composite material. The response gases of the palladium-carbon nanotube composite material under oxygen-free conditions include at least one of hydrogen, carbon monoxide, and ammonia.

[0048] Please refer to Figure 1 , Figure 1 which is the transmission electron microscope image (TEM) of the gas sensing material of one or more embodiments of this application. As shown in the figure, in the palladium-carbon nanotube composite material, palladium nanoparticles are randomly distributed on the surface of the carbon nanotubes.

[0049] Carbon nanotubes (CNTs) are one-dimensional materials with a special structure. Carbon nanotubes are coaxial hollow seamless tubular structure materials formed by curling single or multiple layers of graphite sheets around a center at a certain angle, and most of their tube walls are composed of hexagonal carbon atom grids. According to the number of tube walls, they can be divided into single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). Single-walled carbon nanotubes are composed of a single layer of graphene sheets, and the typical diameters and lengths of single-walled carbon nanotubes are 0.75 - 3 nm and 1 - 50 μm respectively. Thanks to their special structure, single-walled carbon nanotubes have a very high specific surface area and excellent electron transport properties, have a higher current-carrying capacity compared to multi-walled carbon nanotubes, and can quickly respond to external stimuli; at the same time, single-walled carbon nanotubes also have abundant functional groups, which are easy to carry out chemical modification and functionalization to meet the requirements of specific applications.

[0050] Due to the extremely small diameter and high aspect ratio of single-walled carbon nanotubes, the specific surface area of single-walled carbon nanotubes is extremely large, making the corresponding gas sensor have a faster response speed to hydrogen and be able to reach a stable reading in a short time.

[0051] Thanks to the special surface structure, single-walled carbon nanotubes and palladium metal can be compounded. Palladium (Pd) is a platinum group element in Group VIII of the fifth period and belongs to transition metals. There are a large number of defects on the surface of palladium, providing a large number of active sites for gas adsorption. Moreover, the 4d electron layer of palladium lacks two electrons, so it can form chemical bonds with gas molecules.

[0052] In one embodiment, the scale of the palladium-carbon nanotube composite material is at the nanoscale. The nanoscale is the scale of objects with sizes between molecules and the micrometer scale; the linear dimensions of these substances are generally in the range of 0.1 - 100 nm. Nanostructures include one-dimensional, two-dimensional, and three-dimensional systems, and these material units include nanoparticles, nanotubes, nanorods, nanowires, nanoribbons, and nanoscale pores, etc.

[0053] The palladium-carbon nanotube composite combines the gas sensitivity of palladium metal, the high conductivity, and high stability of carbon nanotubes, can effectively adsorb gas molecules, and at the same time can accelerate the diffusion rate of gas on the sensing material. When gas molecules interact with the surface of the gas sensing material, it will cause a change in the surface resistance of the material, generating an obvious electrical signal, and the above process does not require the participation of oxygen, so it can achieve a high-sensitivity response to target gases in an oxygen-free environment.

[0054] According to some embodiments of the present application, the composite material further includes a second metal. Optionally, the second metal includes one or more of copper, silver, gold, and nickel. The second element includes one or more of copper (Cu), silver (Ag), gold (Au), and nickel (Ni). By introducing the above metals, the gas response value can be improved.

[0055] According to some embodiments of the present application, the second metal forms an alloy with palladium or the second metal is a metallic element. By forming an alloy with the above metals or attaching a metallic element of the second metal to the surface of the carbon nanotubes, the gas response value can be improved.

[0056] In some embodiments, the basic principle of alloying palladium metal is to mix two or more different metal elements together through the interaction between atoms to form a new alloy material, such as palladium-gold alloy (Pb-Au), palladium-silver alloy (Pb-Ag), palladium-copper alloy (Pb-Cu), etc. By doping the above metals to form an alloy, the gas response value can be improved.

[0057] By introducing the second metal to achieve alloying of palladium metal, the response behavior of palladium to hydrogen can be changed, which helps to improve and control the adsorption behavior of the gas sensing material to hydrogen. For example, the Pb-Au alloy shows a higher hydrogen solubility than pure Pd, which can accelerate the adsorption of hydrogen and improve the sensitivity and response speed of the gas sensing material; the Pb-Ag alloy has a strong hydrogen absorption ability, making the gas sensing material have high sensitivity and good response repeatability; the Pb-Cu alloy has a strong selective hydrogen permeation ability, which is beneficial to improving the selectivity of the gas sensing material.

[0058] According to some embodiments of the present application, based on the total mass of the composite material, the content of palladium is greater than 0 and less than or equal to 50%, and optionally, greater than 1% and less than or equal to 20%. By controlling the content of palladium within the above range, the gas response value can be improved.

[0059] Theoretically, the higher the content of palladium in the gas sensing material, the better the sensing performance. Because increasing the content of palladium nanoparticles in the palladium-carbon nanotube composite material can increase the gas adsorption sites. However, when there are too many palladium nanoparticles, the sp 2 structure will be damaged, thus hindering the efficient free movement of electrons inside the tube and making the conductivity of the carbon nanotubes worse. Therefore, it is necessary to control the content of palladium nanoparticles within a suitable range to achieve the optimal response effect in terms of the sensitivity and response speed of gas sensing.

[0060] According to some embodiments of the present application, the carbon nanotubes include single-walled carbon nanotubes and / or multi-walled carbon nanotubes. Optionally, the carbon nanotubes further include inorganic non-metallic elements. More optionally, the inorganic non-metallic elements include at least one of N, S, B, P, and F. By selecting or doping and modifying the carbon nanotubes, the gas response value can be improved.

[0061] According to some embodiments of the present application, the response gases of the palladium-carbon nanotube composite material include at least one of hydrogen, carbon monoxide, and ammonia. Please refer to Figure 2 , Figure 2 which is a schematic diagram of the gas response of a gas sensing material according to one or more embodiments. Figure 2 shows the response of the palladium-carbon nanotube composite material to different gases at 1000 ppm.

[0062] The following takes hydrogen as an example for illustration. When Pd is exposed to an H 2 atmosphere, H 2 molecules are physically adsorbed on the Pd surface through van der Waals forces. Then, H 2 molecules dissociate into H atoms on the Pd surface and diffuse into the lattice interstitial sites of Pd, causing the Pd lattice to expand, undergoing a phase change, forming palladium hydride, and causing a change in the electrical signal. This process is a spontaneous process and does not depend on oxygen.

[0063] Furthermore, Pd can react specifically with hydrogen, so it can avoid interference from other gases to a certain extent, endowing the palladium-carbon nanotube composite material with good selectivity for hydrogen detection and improving the accuracy of gas detection. This is because when Pd is exposed to an H 2 atmosphere, H 2 molecules are physically adsorbed on the Pd surface through van der Waals forces. Subsequently, H 2 molecules dissociate into H atoms on the Pd surface and form Pd-H chemical bonds with Pd atoms, and diffuse into the lattice interstitial sites of Pd to form a solid solution, causing the Pd lattice to expand, undergoing a phase change to generate a β-phase that can absorb more H 2 molecules, forming palladium hydride.

[0064] Pd can react specifically with the above others to expand the applicable range. At the same time, it has a strong specific reaction to hydrogen. Therefore, the anti-interference performance of the gas sensing material can be improved.

[0065] In some embodiments of the present application, the Pd in the palladium-carbon nanotube composite material is combined with the carbon nanotubes in the form of palladium nanoparticles, palladium alloy nanoparticles, or second metal nanoparticles. The palladium nanoparticles or palladium alloy nanoparticles have an extremely high specific surface area, so they can provide more adsorption sites for gas molecules. Taking hydrogen (H 2 ) as an example, H 2Molecules are physically adsorbed on the palladium surface through van der Waals forces. Then, H 2 molecules dissociate into H atoms on the palladium surface and diffuse into the interstitial sites of the palladium lattice to form palladium hydride, causing a change in the electrical signal. Palladium in the form of nanoparticles can increase the contact area with hydrogen molecules and provide more abundant hydrogen adsorption sites, thus improving the response speed of the gas sensor.

[0066] In some embodiments of the present application, a method for preparing a gas sensing material is further provided, including: mixing a palladium precursor and a carbon nanotube solution to obtain a mixed solution; drying the mixed solution to obtain a powder; and calcining the powder to obtain a palladium-carbon nanotube composite. The scale of the palladium-carbon nanotube composite is in the nanoscale.

[0067] The palladium-carbon nanotube composite combines the gas sensitivity of palladium metal, the high conductivity and high stability of carbon nanotubes, can effectively adsorb gas molecules, and at the same time can accelerate the diffusion rate of gas on the sensing material and accelerate the charge transfer caused by gas adsorption, enabling the composite material to perform rapid gas sensing response under anaerobic conditions.

[0068] Among them, the palladium precursor is a form of palladium metal before obtaining the target product palladium metal nanoparticles, usually a divalent palladium compound, including palladium salts: such as palladium chloride (PdCl 2 ) or palladium nitrate (Pd(NO3) 2 ); organopalladium compounds: such as palladium acetylacetonate (C 10 H 14 O 4 Pd), palladium acetate (Pd(OAc) 2 ) or palladium aryl compounds; and colloidal palladium, etc.

[0069] In the step of mixing the palladium precursor and the carbon nanotubes, the mixed solution further includes a second metal precursor. The second metal precursor is beneficial to form a palladium alloy or a second metal simple substance with palladium metal.

[0070] The second metal precursor can be chloroauric acid (HAuCl 4 ), silver nitrate (AgNO 3 ), copper nitrate (Cu(NO 3 )) 2 and nickel nitrate (Ni(NO 3 )) 2 ), etc.

[0071] The processes of mixing, drying and calcining the palladium precursor, the second metal precursor and the carbon nanotube solution are called the functionalization of carbon nanotubes, that is, introducing functional groups on the surface of carbon nanotubes. Before the functionalization step, it is usually necessary to purify and acidify the carbon nanotubes.

[0072] Taking single-walled carbon nanotubes as an example, single-walled carbon nanotubes often contain impurities, which may affect subsequent research and applications. Therefore, purification is required. Please refer to Figure 3 , Figure 3 are the scanning electron microscope images (SEM) of single-walled carbon nanotubes before and after purification for one or more embodiments of this application. As shown in the figure, many impurities adhere to the surface of single-walled carbon nanotubes before purification, while the impurities disappear after purification. The purification methods can be divided into physical purification methods, chemical purification methods, and comprehensive purification methods. In some embodiments of this application, the specific purification method is to add 600 mg of unloaded single-walled carbon nanotubes to 300 mL of concentrated hydrochloric acid and ultrasonically clean for 30 min. Use 500 mg of deionized water to perform another 30 min of ultrasonic cleaning on the mixture. Put the cleaned mixture into a drying oven and dry at 150 °C for 10 h to obtain purified unloaded single-walled carbon nanotubes. The above method mainly utilizes the stability of single-walled carbon nanotubes. Single-walled carbon nanotubes are resistant to strong acid and strong base corrosion, while other impurities, such as graphite microparticles, carbon nanoparticles, and fullerenes, have much lower stability than carbon nanotubes and can be removed with acids (such as hydrochloric acid).

[0073] Acidification can increase the active functional groups on the surface of carbon nanotubes, which is actually an oxidation treatment of carbon nanotubes. During the oxidation treatment process, functional groups such as hydroxyl (-OH) and carboxyl (-COOH) on the surface of carbon nanotubes will increase, resulting in changes in the chemical properties and surface properties of carbon nanotubes, making it have good hydrophilicity, higher reactivity, and the property of being easier to form composite materials, etc. In some embodiments of this application, the specific acidification method is to add 400 mg of purified unloaded single-walled carbon nanotubes to 50 mL of concentrated sulfuric acid and 20 mL of concentrated nitric acid, and heat and stir at 80 °C for 4 h. After the mixture cools, dilute it with 60 mL of deionized water. Filter the mixture through a microporous membrane with a pore size of 0.45 μm and wash it repeatedly with deionized water until pH = 7. After drying at 80 °C for 12 h, acidified single-walled carbon nanotubes are obtained. Through the above method, abundant carboxyl and hydroxyl active groups are introduced on the surface of single-walled carbon nanotubes, which is beneficial to the subsequent functionalization of single-walled carbon nanotubes.

[0074] Specifically, in some embodiments of this application, the functionalization method of single-walled carbon nanotubes is to dissolve 200 mg of single-walled carbon nanotubes in 50 mL of isopropanol and ultrasonically treat for 20 min to improve the dispersion of single-walled carbon nanotubes. Dissolve 4 mg of PdCl 2 in 3 mL of ammonia water. Add the PdCl 2 solution dropwise to the SWCNTs / isopropanol mixed solution and stir at high speed for 2 h. Put the obtained suspension into a drying oven and dry at 80 °C for 2 h. Put the obtained powder into a calcination furnace at 600 °C for 2 h. Finally, 1 wt% palladium-single-walled carbon nanotube composite material is synthesized.

[0075] Further, when there is a second metal, taking gold as an example of the second metal, the functionalization method of single-walled carbon nanotubes is that after gradually adding the PdCl 2 solution dropwise into the SWCNTs / isopropanol mixed solution, then 50 μL of 0.01 g / mL HAuCl 4 solution is added dropwise into the solution, and the subsequent steps are the same as above.

[0076] During the functionalization process, the palladium nanoparticles react chemically with the active functional groups (such as carboxyl groups, hydroxyl groups, etc.) on the surface of the single-walled carbon nanotubes to form stable chemical bonds, thereby realizing the composite of palladium nanoparticles and single-walled carbon nanotubes.

[0077] In order to improve the connection strength between the palladium nanoparticles and the carbon nanotubes, in one embodiment, before mixing the palladium precursor with the carbon nanotubes, it further includes mixing the palladium precursor with a linker. By adding the linker, the combination of metallic palladium and the carbon nanotubes can be promoted. The linker can promote the combination of metallic palladium and / or the second metal to the carbon nanotubes.

[0078] The function of the linker is to connect different molecules or materials together. Different linkers have different properties and application ranges, so selecting a suitable linker is the key to realizing the efficient connection of palladium and carbon nanotubes.

[0079] In one embodiment, the linker includes any one of dopamine and cetyltrimethylammonium bromide. By defining the linker, the combination of metallic palladium and the carbon nanotubes can be promoted.

[0080] The connection principle of dopamine (DA) is based on the interaction between the catechol group in the dopamine molecule and various metal ions (such as palladium, copper, zinc, iron, etc.). The catechol group can form stable chelates with metal ions, thereby connecting the metal ions with other molecules or materials together.

[0081] Cetyltrimethylammonium bromide (CTAB) is a cationic surfactant, and its connection principle is based on the interaction between the cations in the CTAB molecule and various materials (such as silicates, aluminates, phosphates, etc.). The cations can interact with the negatively charged groups on the surface of the materials, thereby connecting the materials together.

[0082] In some embodiments of the present application, a gas sensor based on a palladium-carbon nanotube composite material is further provided. The gas sensor includes the gas sensing material of any one of the above; or includes the gas sensing material prepared by using the method of any one of the above.

[0083] Specifically, a palladium-carbon nanotube composite material is used as a gas sensing material. Based on the change in the surface resistance of the sensor when palladium interacts with the target gas, the material realizes the response to the sensed gas, and the carbon nanotubes accelerate the charge transfer, enabling gas response under anaerobic conditions. A gas sensor that can quickly respond to gases and has high detection sensitivity under anaerobic conditions is prepared.

[0084] 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 in conjunction with the embodiments and the 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 in no way limits the present application and its application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0085] I. Preparation of Gas Sensing Material

[0086] Example 1:

[0087] 1. Add 600 mg of unloaded single-walled carbon nanotubes to 300 mL of concentrated hydrochloric acid and ultrasonically clean for 30 min. Use 500 mg of deionized water to perform another 30 min of ultrasonic cleaning on the mixture. Put the cleaned mixture into a drying oven and dry at 150 °C for 10 h to obtain purified unloaded single-walled carbon nanotubes;

[0088] 2. Add 400 mg of purified unloaded single-walled carbon nanotubes to 50 mL of concentrated sulfuric acid and 20 mL of concentrated nitric acid, and heat and stir at 80 °C for 4 h. After the mixture cools, dilute it with 60 mL of deionized water. Filter the mixture through a microporous membrane with a pore size of 0.45 μm and wash it repeatedly with deionized water until pH = 7. After drying at 80 °C for 12 h, obtain acidified single-walled carbon nanotubes;

[0089] 3. Dissolve 200 mg of single-walled carbon nanotubes in 50 mL of isopropanol and ultrasonically treat for 20 min. Dissolve 4 mg of PdCl 2 in 3 mL of ammonia water. Dropwise add the PdCl 2 solution into the SWCNTs / isopropanol mixed solution and stir at high speed for 2 h. Put the obtained suspension into a drying oven and dry at 80 °C for 2 h. Put the obtained powder into a calcination furnace at 600 °C for 2 h. Finally, synthesize 1 wt% palladium-single-walled carbon nanotube composite material Pb / SWCNT-1.

[0090] Examples 2 - 4:

[0091] On the basis of Example 1, the content of palladium was changed. The difference was that the mass of palladium was changed to 12 mg, 40 mg, and 80 mg, and palladium-single-walled carbon nanotube composites Pb / SWCNT-2, Pb / SWCNT-3, and Pb / SWCNT-4 were prepared. The corresponding palladium contents were 3%, 10%, and 20% respectively. Table 1 lists the reaction parameters and performance parameters of each example.

[0092] Example 5:

[0093] On the basis of Example 2, the type of carbon nanotubes was changed. The difference was that single-walled carbon nanotubes were changed to multi-walled carbon nanotubes, and palladium-multi-walled carbon nanotube composite Pb / MWCNT-5 was prepared. The specific reaction conditions are shown in Table 1 for details.

[0094] Example 6:

[0095] On the basis of Example 2, the type of carbon nanotubes was changed. The difference was that the single-walled carbon nanotubes were doped and modified with inorganic non-metals.

[0096] Examples 7-9:

[0097] On the basis of Example 2, a precursor of a second metal was added in the third step.

[0098] Example 10:

[0099] On the basis of Example 2, a linker was added in the third step.

[0100] Comparative example:

[0101] 1. Dissolve 10 mg of palladium acetylacetonate, 20 mg of tungsten hexacarbonyl, and 2 mL of acetic acid in 10 mL of N,N-dimethylformamide solution, and ultrasonically mix evenly in an ice bath for 30 min;

[0102] 2. Place the above solution in an oil bath at 80 °C for 4 h, and then centrifuge the reaction solution at 10000 rpm for 30 min to obtain a black product;

[0103] 3. Wash the above black product with anhydrous ethanol three times, centrifuge at 10000 rpm for 30 min to obtain a black product, wash it with anhydrous ethanol three times, and then place the product in a vacuum oven at 60 °C for 12 h to dry to obtain palladium metal nanosheets Pb-0.

[0104] II. Preparation of gas sensor

[0105] The palladium-carbon nanotube composite material was added to terpineol at a concentration of 10 mg / L and sonicated for 10 min at 40 KHz to uniformly disperse the composite material in terpineol, thereby obtaining a dispersion of palladium-carbon nanotubes. A gold electrode was prepared by a microfabrication process, and the distance between the positive and negative electrodes was controlled to be 800 μm, and the distance between adjacent electrodes was 300 μm. 5 μL of the above dispersion was taken and dropped onto the interdigital electrode. It was dried in vacuo at 60 °C for 1 h to obtain a palladium-carbon nanotube hydrogen sensor.

[0106] III. Gas sensing performance test

[0107] Please refer to Figure 4 , the gas sensor was placed in the test chamber. At room temperature, the target gas was introduced by the static gas distribution method, and the resistance change of the sensor in the inert gas and in the environment of different concentrations of the target gas was monitored in real time by an Agilent 4156C semiconductor parameter analyzer. A constant working voltage of 500 mV was applied between the sensor electrodes, and the test was carried out with reference to Standard GB / T3634 - 1995 4.5. Before introducing the target gas, the chamber was purged with dry compressed argon (MFC3) to stabilize the baseline signal, and compressed argon (MFC2) was used as the carrier gas to dilute the target gas at different concentrations, and the target gas was controlled by a mass flow controller (MFC1). The difference in the resistance of the sensor in dry argon and in the target gas and the ratio of the resistance in dry argon (|R a -R g | / R a × 100%) is the response value of the device to the target gas at this concentration. The response time and the recovery time are defined by reaching 90% saturation of the response and recovery curves. The test results are as follows:

[0108] 1. Comparison of different examples

[0109] Please refer to Table 1 first. Table 1 is a table of reaction parameters and performance parameters for each example and comparative example.

[0110] Table 1 Table of reaction parameters and performance parameters for each example and comparative example

[0111]

[0112] Note: In the table, "Pd content" refers to the proportion of Pd in the total mass of the Pd-carbon nanotube composite material, "single-walled" represents semiconductor single-walled carbon nanotubes, "multi-walled" represents multi-walled carbon nanotubes, and single-walled (B-doped) represents non-metallic B-modified single-walled carbon nanotubes. The gases for testing the response value and response time are both 1000 ppm hydrogen.

[0113] By comparing Examples 1 - 4, 6 - 10 with the comparative examples, it can be seen that the response value of the palladium-carbon nanotubes is relatively high.

[0114] By comparing Example 5 with the comparative example, it can be seen that both the response time and the recovery time of palladium-carbon nanotubes are relatively fast.

[0115] 2. H 2 Response and recovery dynamic test

[0116] As Figures 5 - 9 shown, the response of the sensors of the gas sensing materials prepared in different examples and comparative examples of the present application to hydrogen was tested at room temperature.

[0117] 3. H 2 Cyclic stability test

[0118] At room temperature, multiple response and recovery tests of the palladium-carbon nanotube gas sensing material prepared in Example 2 of the present invention to 1000 ppm hydrogen were carried out, data was obtained and analyzed, and the background gas in the test was argon. The results are as Figure 10 shown. In the figure, the abscissa is the acquisition time and the ordinate is the device sensitivity. After three response-recovery cycles, the response value of the sensor remains basically unchanged, maintaining above 3.4%, and at the same time, the response time remains basically unchanged, about 100 s. The above results show that the sensor prepared in the foregoing example has good cyclic stability during the response and recovery process to H 2 2.

[0119] 4. Gas selectivity test

[0120] Please refer to Figure 2 , Figure 2 which is a schematic diagram of the response of the palladium-carbon nanotube gas sensing material according to one or more embodiments of the present application to different gases at the same concentration. It can be seen from the figure that the gas sensing material has response values to hydrogen, carbon monoxide and ammonia. However, it shows excellent selectivity to hydrogen.

[0121] In some embodiments of the present application, the gas sensor can be used for detecting the gas inside the battery. That is, the present application provides a battery, and the battery includes the gas sensor of the above embodiment.

[0122] Please refer to Figure 11 , Figure 11Schematic exploded view of a battery according to one or more embodiments. The battery 100 includes a box body 10 and battery cells 20, and the battery cells 20 are accommodated in the box body 10. Among them, the box body 10 is used to provide an accommodation space for the battery cells 20, and the box body 10 can adopt various structures. In some embodiments, the box body 10 may include a first part 11 and a second part 12, the first part 11 and the second part 12 cover each other, and the first part 11 and the second part 12 jointly define an accommodation space for accommodating the battery cells 20. The second part 12 may be a hollow structure with one end open, and the first part 11 may be a plate-like structure. The first part 11 covers the open side of the second part 12 so that the first part 11 and the second part 12 jointly define an accommodation space; the first part 11 and the second part 12 may also both be hollow structures with one side open, and the open side of the first part 11 covers the open side of the second part 12. Of course, the box body 10 formed by the first part 11 and the second part 12 can be of various shapes, such as a cylinder, a cuboid, etc.

[0123] In the battery 100, there may be multiple battery cells 20, and the multiple battery cells 20 can be connected in series, parallel or in a mixed connection. A mixed connection means that there are both series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 can be directly connected in series, parallel or in a mixed connection together, and then the whole formed by the multiple battery cells 20 is accommodated in the box body 10; of course, the battery 100 can also be that multiple battery cells 20 are first connected in series, parallel or in a mixed connection to form a battery module form, and then multiple battery modules are connected in series, parallel or in a mixed connection to form a whole and are accommodated in the box body 10. The battery 100 may further include other structures. For example, the battery 100 may further include a busbar component for realizing electrical connection among the multiple battery cells 20.

[0124] Among them, each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited thereto. The battery cell 20 can be in the shape of a cylinder, a flat body, a cuboid or other shapes, etc.

[0125] Please refer to Figure 12 , Figure 12 Schematic exploded view of a battery cell according to one or more embodiments. A battery cell 20 refers to the smallest unit that makes up a battery. As Figure 12 shown, the battery cell 20 includes an end cap 21, a housing 22, an electrode assembly 23 and other functional components.

[0126] The end cap 21 refers to a component that covers the opening of the housing 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 housing 22 to fit the housing 22. Optionally, the end cap 21 can be made of a material with a certain hardness and strength (such as aluminum alloy). In this way, the end cap 21 is not easily deformed when subjected to extrusion and collision, enabling the battery cell 20 to have higher structural strength and improved safety performance. Functional components such as electrode terminals 21a can be provided on the end cap 21. The electrode terminals 21a can be used for electrical connection with the electrode assembly 23 to output or input the electrical energy of the battery cell 20. In some embodiments, a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold can also be provided on the end cap 21. The material of the end cap 21 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not make special restrictions on this. In some embodiments, an insulating member can also be provided on the inner side of the end cap 21, and the insulating member can be used to isolate the electrical connection components in the housing 22 from the end cap 21 to reduce the risk of short circuit. Exemplarily, the insulating member can be plastic, rubber, etc.

[0127] The housing 22 is a component for cooperating 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, the electrolyte, and other components. The housing 22 and the end cap 21 can be independent components. An opening can be provided on the housing 22, and the end cap 21 is covered on the opening to form the internal environment of the battery cell 20. Without limitation, the end cap 21 and the housing 22 can also be integrated. Specifically, the end cap 21 and the housing 22 can first form a common connection surface before other components are inserted into the housing, and when it is necessary to encapsulate the inside of the housing 22, the end cap 21 is then covered on the housing 22. The housing 22 can be of various shapes and sizes, such as cuboid, cylindrical, 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 material of the housing 22 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not make special restrictions on this.

[0128] The electrode assembly 23 is a component in the battery cell 100 where an electrochemical reaction occurs. The housing 22 can contain one or more electrode assemblies 23. The electrode assembly 23 is mainly formed by winding or laminating a positive electrode sheet and a negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. The portions of the positive electrode sheet and the negative electrode sheet having active materials constitute the main body of the electrode assembly, and the portions of the positive electrode sheet and the negative electrode sheet without active materials respectively constitute the electrode tabs 23a. The positive electrode tab and the negative electrode tab can be located together at one end of the main body or separately at both ends of the main body. During the charge and discharge process of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte, and the electrode tabs 23a are connected to the electrode terminals to form a current loop.

[0129] In one embodiment, the positive electrode sheet includes a current collector and a positive electrode active layer provided on the current collector.

[0130] The positive electrode active layer includes a positive electrode active material, and the positive electrode active material can include at least one of the following materials: lithium phosphate 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 conventional materials that can be used as battery positive electrode active materials can also be used. These positive electrode active materials can be used alone or in combination of two or more. Among them, examples of lithium transition metal oxides can include, but are not limited to, lithium cobalt oxide (such as LiCoO 2 ), lithium nickel oxide (such as LiNiO 2 ), lithium manganese oxide (such as LiMnO 2 , LiMn 2 O 4 ), 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 O 2 (which can also be abbreviated as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (which can also be abbreviated as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (which can also be abbreviated as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (which can also be abbreviated as NCM 622 ), LiNi 0.8 Co 0.1 Mn0.1 O 2 (which can also be abbreviated as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O 2 ), and at least one of its modified compounds, etc. Examples of olivine-structured lithium-containing phosphates may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (which can also be abbreviated as LFP)), composites of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), composites of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and composites of lithium manganese iron phosphate and carbon.

[0131] In one embodiment, the positive electrode active layer further includes a conductive agent to endow the electrode with conductivity. The positive electrode conductive material can include any conductive material as long as it does not cause chemical changes. Non-limiting examples of the positive electrode conductive material 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. Optionally, the conductive agent includes one or more of conductive carbon black, conductive graphite, carbon fiber, carbon nanotube, graphene, Ketjen black, and acetylene black.

[0132] 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 falling off. The binder can be one or several 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). Optionally, the binder includes one or several of polyvinylidene fluoride, polytetrafluoroethylene, acrylate, and polyurethane.

[0133] In one embodiment, the positive electrode active layer further includes other optional additives, and the other optional additives can be thickening and dispersing agents (such as sodium carboxymethyl cellulose CMC-Na), PTC thermistor materials.

[0134] In some embodiments, the negative electrode tab includes a current collector and a negative electrode active layer disposed on the current collector.

[0135] The negative electrode active layer includes negative electrode active materials, which include but are 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 including but not limited to graphite materials, silicon-carbon materials, graphite-silicon monoxide materials, nano-silicon materials, silicon monoxide materials, and tin-based materials; more specifically including natural graphite, artificial graphite, mesocarbon microbeads (abbreviated as MCMB), hard carbon, soft carbon, silicon, silicon-carbon composites, Li-Sn alloys, Li-Sn-O alloys, Sn, SnO, SnO 2 and lithiated TiO with a spinel structure 2 -Li 4 Ti 5 O 12 , one or more of Li-Al alloys.

[0136] 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 (such as sodium carboxymethyl cellulose CMC-Na), PTC thermistor materials.

[0137] In some embodiments, the material of the separator may be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may 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 may be the same or different, without particular limitation.

[0138] In one embodiment, the electrolyte includes one or more of carbonate solvents and ether solvents.

[0139] Carbonates are usually small-molecule cyclic or chain carbonates; including but not limited to one or more of ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, methyl propyl carbonate, dipropyl carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, and fluorinated carbonates; it may also be at least one ester solvent of γ-butyrolactone, dimethyl sulfite, ethyl acetate, methyl acetate, methyl butyrate, ethyl butyrate, methyl propionate, ethyl propionate, propyl acetate, and fluorinated carboxylate.

[0140] Ether solvents include, but are not limited to, one or more of dimethyl ether, diethyl ether, tetrahydrofuran, methyltetrahydrofuran, ethylene oxide, 1,3-dioxolane, fluoroethers, 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.

[0141] In other embodiments, the electrolyte may further include a mixture composed of any one or several of amine solvents, sulfone solvents, and nitrile solvents. Amine solvents include at least one of N-methylacetamide, N-methylformamide, dimethylformamide, and diethylformamide. Sulfone solvents include at least one of dimethyl sulfoxide, sulfolane, diphenyl sulfoxide, thionyl chloride, and dipropyl sulfone. Nitrile solvents include at least one of acetonitrile, succinonitrile, adiponitrile, and glutaronitrile. The electrolyte is preferably a high-voltage-resistant electrolyte, whose acidity weakens under high voltage, which is beneficial to the transport of active ions, significantly reduces side reactions on the electrode surface, and improves battery stability.

[0142] In some embodiments, the electrolyte further includes an electrolyte salt, and the electrolyte salt may 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 difluoro(oxalato)borate, lithium bis(oxalato)borate, lithium difluoro bis(oxalato)phosphate, and lithium tetrafluoro(oxalato)phosphate.

[0143] In some embodiments, the electrolyte may optionally further include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery performance, such as additives for improving battery overcharge performance, additives for improving battery high-temperature or low-temperature performance, and the like.

[0144] The battery disclosed in the embodiments of the present application can be used in electrical equipment using the battery as a power source or various energy storage systems using the battery as an energy storage element. That is, an electrical equipment is provided. In some embodiments, the electrical equipment of the present application can be used in, but is not limited to, laptop computers, pen-input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, head-mounted stereo headphones, video recorders, liquid crystal televisions, hand-held cleaners, portable CD players, minidiscs, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, motorized bicycles, bicycles, ships, spacecraft, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries, and lithium-ion capacitors, etc.

[0145] The battery disclosed in the embodiments of the present application can be used in electrical equipment that uses the battery as a power source or various energy storage systems that use the battery as an energy storage element. That is, the present application provides an electrical equipment, and the electrical equipment includes the battery of the above embodiments. In some embodiments, the electrical equipment of the present application can be used in, but is 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, liquid crystal TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, motorized bicycles, bicycles, ships, spacecrafts, lighting appliances, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries, and lithium-ion capacitors, etc.

[0146] The electrical equipment can select battery cells, battery modules, or battery packs according to its usage requirements.

[0147] Please refer to Figure 13 , Figure 13 FIG. 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, an extended-range vehicle, etc. A battery 100 is disposed inside the vehicle 1000, and the battery 100 can be disposed at the bottom, head, or tail of the vehicle 1000. The battery 100 can be used to supply power to the vehicle 1000. For example, the battery 100 can be used as the operating power source of the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300. For example, it is used for the working power requirements during the start, navigation, and driving of the vehicle 1000.

[0148] In some embodiments of the present application, the battery 100 can not only be used as the operating power source of the vehicle 1000, but also as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0149] The above are only the embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be included in the patent protection scope of the present application by the same token.

Claims

1. A gas sensing material, characterized in that, it comprises: a palladium-carbon nanotube composite material, and the response gases of the palladium-carbon nanotube composite material under anaerobic conditions include at least one of hydrogen, carbon monoxide and ammonia.

2. The gas sensing material according to claim 1, characterized in that, the composite material further comprises a second metal, optionally, the second metal comprises one or more of copper, silver, gold and nickel.

3. The gas sensing material according to claim 1 or 2, characterized in that, the second metal forms an alloy with palladium or the second metal is a metallic element.

4. The gas sensing material according to any one of claims 1 to 3, characterized in that, based on the total mass of the composite material, the content of palladium is greater than 0 and less than or equal to 50%, optionally, greater than or equal to 1% and less than or equal to 20%.

5. The gas sensing material according to any one of claims 1 to 4, characterized in that, the carbon nanotubes include single-walled carbon nanotubes and / or multi-walled carbon nanotubes; optionally, the carbon nanotubes are single-walled carbon nanotubes.

6. The gas sensing material according to any one of claims 1 to 5, characterized in that, the carbon nanotubes further comprise inorganic non-metallic elements, optionally, the inorganic non-metallic elements include at least one of N, S, B, P and F.

7. A preparation method of a gas sensing material, characterized in that, it comprises: mixing a palladium precursor and a carbon nanotube solution to obtain a mixed solution; drying the mixed solution to obtain a powder; calcining the powder to obtain a palladium-carbon nanotube composite material.

8. The preparation method of the gas sensing material according to claim 7, characterized in that, in the step of mixing the palladium precursor and the carbon nanotubes, the mixed solution further comprises a second metal precursor.

9. The preparation method of the gas sensing material according to claim 7 or 8, characterized in that, in the step of mixing the palladium precursor and the carbon nanotubes, the mixed solution further comprises a linker.

10. The preparation method of the gas sensing material according to claim 9, characterized in that, the linker includes any one of dopamine and cetyltrimethylammonium bromide.

11. A gas sensor, characterized in that, it comprises the gas sensing material according to any one of claims 1 to 6; or it comprises the gas sensing material prepared by the method according to any one of claims 7 to 10.

12. A battery, characterized in that, it comprises the gas sensor according to claim 11.

13. An electrical device, characterized in that, it comprises the battery according to claim 12.

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