Self-heating material as well as preparation method and application thereof

Abstract

The invention provides a spontaneous heating material and a preparation method and application thereof. The self-heating material comprises a positive electrode material layer and a negative electrode material layer, and the positive electrode material layer and the negative electrode material layer are attached to each other; the positive electrode material layer comprises a carbon-based material; the porosity of the negative electrode material layer is 20%-50%; and the negative electrode material layer comprises a porous metal material. The positive electrode material layer of the self-heating material contains the carbon-based material with the specific particle size, the positive electrode material layer and the negative electrode material layer are attached and make contact with the alkaline electrolyte, the alkaline electrolyte can penetrate through pores of the negative electrode material layer to make contact with the positive electrode material and the negative electrode material, and after contact, a short-circuit reaction of the metal-air battery occurs; therefore, heating is realized. The self-heating material has the advantages of being rapid in heating, controllable in temperature, long in heating time and the like.

Description

Technical Field

[0001] The present application relates to the technical field of self-heating materials, and in particular to a self-heating material, a preparation method thereof, and an application thereof. Background Art

[0002] Self-heating materials refer to materials that can generate heat through chemical reactions or physical processes. Among them, chemical reaction type self-heating materials are the most common. The principle is that chemical heating agents can produce chemical reactions and release heat when they come into contact with specific conditions (such as air, moisture or other chemicals).

[0003] Self-heating technology originated from the self-heating food for individual soldiers developed to meet the needs of military field operations, in which self-heating materials are the core component of self-heating technology. The earliest self-heating technology used the hydration reaction of quicklime to release heat. The principle is that heat is released during the reaction of CaO and H2O to generate Ca(OH)2. No harmful gases are produced in this reaction process, but there are disadvantages such as low heat release, easy moisture absorption of the heating pack, and short shelf life. Therefore, this type of self-heating material has been gradually eliminated.

[0004] At present, self-heating materials have been widely used in the fields of self-heating food and medical care and beauty, and their market usage is increasing. Commonly used self-heating materials mainly include aluminum-based self-heating agents, magnesium-based self-heating agents and iron-based self-heating agents; when micro-nano-scale metal aluminum particles or metal magnesium particles come into contact with water, a hydration reaction will occur on their surface to generate hydroxides with a loose porous structure and release heat; however, this process will also produce hydrogen, which poses certain safety hazards. In contrast, the oxidation reaction rate of iron under natural conditions is slow; therefore, by combining water, inorganic salts, activated carbon and iron powder to form a primary battery, the oxidation reaction rate can be accelerated and chemical energy can be converted into thermal energy; however, the heating temperature of this type of heating agent is relatively low, which usually cannot meet the needs of heating food and beverages.

[0005] At present, the heat release principles of commonly used self-heating materials mainly include aluminum thermite reaction, iron oxidation corrosion heat release, redox reaction heat release, aluminum water reaction heat release, magnesium water reaction heat release, etc. However, the self-heating materials based on the above reactions have some shortcomings, such as slow heating speed, too violent reaction and difficult temperature control.

[0006] Therefore, traditional self-heating materials still need to be further improved. Summary of the invention

[0007] Based on this, one or more embodiments of the present application provide a self-heating material that is easy to use, generates heat quickly, and has controllable temperature, as well as a preparation method and application thereof.

[0008] According to the first aspect of the present application, a self-heating material is provided, comprising a positive electrode material layer and a negative electrode material layer, wherein the positive electrode material layer and the negative electrode material layer are bonded to each other; the positive electrode material layer comprises a carbon-based material; the porosity of the negative electrode material layer is 20% to 50%; and the negative electrode material layer comprises a porous metal material.

[0009] In some embodiments, the mass ratio of the negative electrode material layer to the positive electrode material layer is 1:(0.3~0.5).

[0010] In some embodiments, the porous metal material includes one or more of a metal mesh, a porous metal plate, a porous metal foil, and a porous metal belt.

[0011] In some embodiments, the porous metal material is made of one or more of aluminum, magnesium, zinc and iron.

[0012] In some embodiments, the carbon-based material includes one or more of activated carbon, graphite, expanded graphite, carbon nanotubes, graphene, conductive carbon black and acetylene black.

[0013] In some embodiments, the particle size of the activated carbon is 200 mesh to 400 mesh.

[0014] In some embodiments, the positive electrode material layer further includes one or more of a catalyst and a binder;

[0015] Optionally, the catalyst includes one or more of noble metals and alloys thereof, transition metal oxides, transition metal sulfides, functionalized carbon materials and metal nitrides;

[0016] Optionally, the binder includes one or more of polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl alcohol and potassium polyacrylate.

[0017] According to the second aspect of the present application, a method for preparing the above-mentioned self-heating material is provided, comprising the following steps:

[0018] Mixing the carbon-based material with a solvent to prepare a positive electrode slurry;

[0019] The positive electrode slurry is coated on the negative electrode material layer, and the self-heating material is obtained by drying and cold pressing.

[0020] In some embodiments, the preparation method satisfies at least one of the following characteristics:

[0021] (1) The drying temperature is 25°C to 40°C;

[0022] (2) The cold pressing pressure is 5 MPa to 15 MPa.

[0023] According to a third aspect of the present application, a self-heating component is provided, comprising an alkaline electrolyte and the self-heating material described above, wherein the alkaline electrolyte and the self-heating material are placed separately.

[0024] In some embodiments, the alkaline electrolyte includes one or more of potassium hydroxide and its hydrates, sodium hydroxide and its hydrates, lithium hydroxide and its hydrates, calcium hydroxide and its hydrates, potassium carbonate and its hydrates, sodium carbonate and its hydrates, lithium carbonate and its hydrates, calcium carbonate and its hydrates, potassium bicarbonate and its hydrates, sodium bicarbonate and its hydrates, lithium bicarbonate and its hydrates, and calcium bicarbonate and its hydrates.

[0025] According to a fourth aspect of the present application, a self-heating device is provided, comprising the above-mentioned self-heating component.

[0026] According to a fifth aspect of the present application, an application method of the above-mentioned self-heating device is provided, wherein an alkaline electrolyte is brought into contact with a self-heating material.

[0027] According to the sixth aspect of the present application, a heated cigarette smoke body is provided, comprising an aerosol matrix, cigarette paper and the above-mentioned self-heating material; the cigarette paper is wrapped around the outside of the aerosol matrix, and the self-heating material is located between the aerosol matrix and the cigarette paper.

[0028] According to a seventh aspect of the present application, a heated cigarette is provided, comprising the heated cigarette smoke-generating body described above.

[0029] Compared with the traditional technology, this application has the following beneficial effects:

[0030] The positive electrode material layer of the self-heating material of the present application contains a specific carbon-based material. The positive electrode material layer is attached to the negative electrode material layer and is in contact with an alkaline electrolyte. The alkaline electrolyte can pass through the pores of the negative electrode material layer and contact the positive electrode material and the negative electrode material. After the three are in contact, a short-circuit reaction of the metal-air battery occurs, thereby generating heat. The self-heating material of the present application has the advantages of rapid heating, controllable temperature, and long-lasting heating time. In addition, the self-heating material of the present application does not need to be isolated from the air during storage, and storage is more convenient; no exogenous water and high-temperature triggering conditions are required during the reaction, and no dangerous products are generated, and the safety factor is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 This is a schematic diagram of the structure of a heated cigarette smoke-generating body in one embodiment of the present application.

[0033] Explanation of reference numerals: 10, aerosol matrix; 20, cigarette paper; 30, self-heating material; 31, positive electrode material layer; 32, negative electrode material layer. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present application. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. Unless otherwise specifically stated, various raw materials, reagents, instruments and equipment used in the present application, etc. can be purchased from the market or can be prepared by existing methods.

[0036] There are many types of self-heating materials commonly used in traditional technologies, but there are still some inevitable defects. For example: high requirements for the storage environment and the need to be isolated from the air; the need to add exogenous water to start the reaction or high temperature conditions to start the reaction, and the reaction is violent and difficult to control; dangerous substances such as hydrogen will be produced during the reaction, posing a safety risk; the heating rate is slow and the maximum temperature that can be reached is low.

[0037] The heating device in the heated cigarette does not burn the cigarette. Its working principle is to heat the tobacco segment to a certain temperature through the heating device, so that the tobacco in the tobacco segment produces aerosol, thereby releasing nicotine and other effective ingredients for use. The applicant has found through a lot of practice that the introduction of self-heating materials in heated cigarettes can partially replace the heat released by the heating device; however, traditional self-heating materials are not suitable for the field of heated cigarettes.

[0038] Based on this, some embodiments of the present application provide a self-heating material, including a positive electrode material layer and a negative electrode material layer, the positive electrode material layer and the negative electrode material layer are bonded to each other; the positive electrode material layer includes a carbon-based material; the porosity of the negative electrode material layer is 20%~50%; the negative electrode material layer includes a porous metal material.

[0039] The above-mentioned self-heating material of the present application combines the positive electrode material and the negative electrode material of the layered structure, which can reduce dust generation and harm to the human body compared with the traditional granular or powdered electrode materials. When in use, the positive electrode material and the negative electrode material are attached and contacted with the alkaline electrolyte. The alkaline electrolyte can pass through the porous structure of the negative electrode material layer and contact the positive electrode material and the negative electrode material at the same time, causing a short-circuit reaction of the metal-air battery, thereby achieving heat generation.

[0040] The present application controls the porosity of the negative electrode material layer in the self-heating material within the above-mentioned specific range, which can facilitate the penetration of alkaline electrolyte on the one hand, and ensure that there is enough negative electrode material to react with the alkaline electrolyte on the other hand, so that the alkaline electrolyte can quickly generate heat after penetration.

[0041] As an example, the porosity of the negative electrode material layer in the self-heating material can be 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, or any value within the range formed by any two of the above point values.

[0042] Furthermore, the porosity of the negative electrode material layer in the self-heating material is 20% to 30%.

[0043] In some embodiments, the particle size of the carbon-based material is 200 mesh to 400 mesh.

[0044] In some optional embodiments, the particle size of the carbon-based material is 200 mesh to 400 mesh. As an example, the particle size of the carbon-based material can be 200 mesh, 225 mesh, 250 mesh, 275 mesh, 300 mesh, 325 mesh, 350 mesh, 375 mesh, 400 mesh, or any value within the range formed by any two of the above point values.

[0045] It can be understood that in the present application, 200-400 mesh refers to the material under the 200-mesh sieve and the material on the 400-mesh sieve.

[0046] As an example, at least a portion of the positive electrode material layer and at least a portion of the negative electrode material layer are bonded to each other.

[0047] As an example, the areas of the positive electrode material layer and the negative electrode material layer may be the same, that is, all regions of the positive electrode material layer are completely in contact with all regions of the negative electrode material layer.

[0048] In some of the embodiments, the mass ratio of the negative electrode material layer to the positive electrode material layer is 1:(0.3~0.5).

[0049] The present application controls the mass ratio of the negative electrode material layer and the positive electrode material layer within the above range, which can further improve the heating efficiency, so that the maximum temperature of the self-heating reaction after the addition of the alkaline electrolyte is within a controllable range and can be quickly heated to above 50°C.

[0050] As an example, the mass ratio of the negative electrode material layer to the positive electrode material layer can be 1:0.3, 1:0.31, 1:0.32, 1:0.33, 1:0.34, 1:0.35, 1:0.36, 1:0.37, 1:0.38, 1:0.39, 1:0.4, 1:0.41, 1:0.42, 1:0.43, 1:0.44, 1:0.45, 1:0.46, 1:0.47, 1:0.48, 1:0.49, 1:0.5, or any value within the range formed by any two of the above point values.

[0051] In some embodiments, the porous metal material includes one or more of a metal mesh, a porous metal plate, a porous metal foil and a porous metal belt. It is understandable that the negative electrode material layer may also be other materials having a continuous shape.

[0052] In the present application, a porous metal material with a continuous shape such as a metal mesh, a porous metal plate, a porous metal foil or a porous metal belt is used as the negative electrode material layer, which can reduce the debris and dust generated during the storage process and the reaction process, thereby reducing pollution to the environment and harm to human health.

[0053] In some embodiments, the porous metal material includes one or more of aluminum, magnesium, zinc, and iron.

[0054] In some optional embodiments, the metal negative electrode material is selected from aluminum and magnesium; optionally, the mass ratio of aluminum to magnesium is 9:1.

[0055] In some optional embodiments, the metal negative electrode material is selected from aluminum and zinc; optionally, the mass ratio of aluminum to zinc is 9:1

[0056] In some optional embodiments, the porous metal material is selected from aluminum, for example, it can be one or more of aluminum wire mesh, porous aluminum plate, porous aluminum foil and porous aluminum tape.

[0057] When aluminum is used as the negative electrode material and in contact with an alkaline electrolyte, the negative electrode reaction is Al+4OH - →Al(OH)4 - +3e - ; The positive electrode reaction is O2+2H2O+4e - →4OH -The total reaction is 4Al+3O2+6H2O→4Al(OH)3 (△H=-31.72kJ / g). This reaction can occur at room temperature. The oxygen in the air is adsorbed by activated carbon to form the "positive electrode site" of the primary battery. After adding inorganic electrolyte, it will form several micro short-circuit points between the "negative electrode site" of the negative electrode metal, and the reaction rate will increase.

[0058] In some embodiments, the carbon-based material includes one or more of activated carbon, graphite, expanded graphite, carbon nanotubes, graphene, conductive carbon black and acetylene black. It is understandable that the raw materials for preparing the positive electrode material layer may also include other carbon-based materials commonly used in the art.

[0059] In some optional embodiments, the carbon-based material is selected from activated carbon and acetylene black.

[0060] In some embodiments, the positive electrode material layer further includes one or more of a catalyst and a binder.

[0061] In some optional embodiments, the catalyst includes one or more of noble metals and alloys thereof, transition metal oxides, transition metal sulfides, functionalized carbon materials, and metal nitrides. As an example, the types of catalysts include but are not limited to manganese dioxide.

[0062] In some optional embodiments, the binder includes one or more of polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl alcohol and potassium polyacrylate.

[0063] In some optional embodiments, the positive electrode material layer includes activated carbon, acetylene black and a binder. As an example, the mass ratio of activated carbon, acetylene black and the binder is 5:3:2.

[0064] In some optional embodiments, the raw materials for preparing the positive electrode material layer include activated carbon, acetylene black, a binder and a catalyst. As an example, the mass ratio of activated carbon, acetylene black, a binder and a catalyst is 4:3:2:1.

[0065] In some embodiments, the raw materials for preparing the positive electrode material layer further include a solvent.

[0066] In some optional embodiments, the solvent includes one or more of water, ethanol, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide.

[0067] The above-mentioned self-heating material of the present application does not need to be isolated from air during storage, and does not need to add exogenous water or exogenous heat to start the reaction, and has the advantages of convenient storage and use; and has the advantages of being light and thin, heating up quickly, temperature controllable, no risk of combustion and explosion, and high heating efficiency.

[0068] The above-mentioned self-heating material of the present application can reach a high temperature of more than 50°C within 15 seconds, and can maintain a temperature above 50°C for more than 40 seconds; the maximum temperature can be controlled within 50°C~150°C.

[0069] Some embodiments of the present application also provide a method for preparing the above-mentioned self-heating material, including S10 to S20.

[0070] S10: Mixing the carbon-based material with a solvent to prepare a positive electrode slurry.

[0071] It should be noted that the types of carbon-based materials are as described above and will not be repeated here.

[0072] In some embodiments, S10 includes the following steps:

[0073] S11: mixing the carbon-based material with the binder, and grinding to obtain a solid mixture;

[0074] S12: The solid mixture is mixed with a solvent, and a positive electrode slurry is obtained by ultrasonic vibration.

[0075] In some optional embodiments, the content of solid matter in the positive electrode slurry is 25 g / mL. The solid matter includes a carbon-based material and a binder.

[0076] S20: coating the positive electrode slurry onto the negative electrode material layer, and obtaining a self-heating material through drying and cold pressing.

[0077] In some embodiments, the drying temperature in S20 is 25°C to 40°C.

[0078] As an example, the drying temperature can be 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, or any value within the range formed by any two of the above point values.

[0079] In some embodiments, the cold press forming pressure is 5 MPa to 15 MPa.

[0080] As an example, the pressure of cold press molding can be 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, 10 MPa, 11 MPa, 12 MPa, 13 MPa, 14 MPa, 15 MPa, or any value within the range formed by any two of the above point values. Optionally, the pressure of cold press molding is 8 MPa.

[0081] The method for preparing the self-heating material of the present application can prepare the self-heating material by simultaneously pressing the positive electrode material and the negative electrode material, and the preparation process is simple.

[0082] Some embodiments of the present application also provide a self-heating component, including an alkaline electrolyte and the self-heating material described above, wherein the alkaline electrolyte and the self-heating material are placed separately.

[0083] In some embodiments, the alkaline electrolyte includes one or more of potassium hydroxide and its hydrates, sodium hydroxide and its hydrates, lithium hydroxide and its hydrates, calcium hydroxide and its hydrates, potassium carbonate and its hydrates, sodium carbonate and its hydrates, lithium carbonate and its hydrates, calcium carbonate and its hydrates, potassium bicarbonate and its hydrates, sodium bicarbonate and its hydrates, lithium bicarbonate and its hydrates, and calcium bicarbonate and its hydrates.

[0084] In some optional embodiments, the alkaline electrolyte is a liquid electrolyte. It can be understood that the liquid electrolyte is easier to pass through the pores on the surface of the negative electrode material in the self-heating material, thereby improving the heating efficiency.

[0085] Some embodiments of the present application also provide a self-heating device, comprising the self-heating component described above.

[0086] Some embodiments of the present application also provide an application method of the above-mentioned self-heating device, which is to contact the alkaline electrolyte with the self-heating material.

[0087] Some embodiments of the present application also provide a heated cigarette smoke body, including an aerosol matrix 10, a cigarette paper 20 and the above-mentioned self-heating material 30; the cigarette paper 20 is wrapped around the outside of the aerosol matrix 10, and the self-heating material 30 is located between the aerosol matrix 10 and the cigarette paper 20.

[0088] The self-heating material 30 includes a positive electrode material layer 31 and a negative electrode material layer 32 .

[0089] In some embodiments, the structure of the heated cigarette smoking body is as follows Figure 1 shown.

[0090] It is understandable that the present application does not specifically limit the positional relationship between the positive electrode material layer 31 and the negative electrode material layer 32 in the heated cigarette smoke body, that is, the positive electrode material layer 31 can be located on the side in contact with the aerosol matrix 10, or on the side in contact with the cigarette paper 20.

[0091] The heated cigarette smoke body of the present application includes the above-mentioned self-heating device. When in use, the alkaline electrolyte is brought into contact with the self-heating material to quickly release a certain amount of heat, which can reduce the amount of heat required to be provided by the external heating device.

[0092] As an example, the alkaline electrolyte in the heated cigarette can be dripped into the space between the positive electrode material and the negative electrode material through the needle tip of a syringe.

[0093] Some embodiments of the present application also provide a heated cigarette, comprising the heated cigarette smoke-generating body described above.

[0094] In some of the embodiments, the heated cigarette further includes a hollow section and a filter section; the filter section, the hollow section and the heated cigarette smoking body are arranged in sequence.

[0095] The present application will be further described below in conjunction with specific examples and comparative examples, but they should not be construed as limiting the scope of protection of the present application. The raw materials involved in the following specific examples, unless otherwise specified, can all be sourced from commercial sources, the instruments used, unless otherwise specified, can all be sourced from commercial sources, and the processes involved, unless otherwise specified, are all conventionally selected by those skilled in the art.

[0096] Example 1

[0097] (1) In terms of mass percentage, 50 wt% activated carbon, 30 wt% acetylene black and 20 wt% binder polytetrafluoroethylene were provided and ground for 10 minutes to make them uniformly mixed; an organic solvent N-methylpyrrolidone was added to disperse them until the total content of the solid matter was 25 g / mL, and then ultrasonic vibration was performed for 30 minutes to form a uniform and stable paste-like slurry.

[0098] Among them, the particle size of activated carbon is 325 mesh, and the particle size of acetylene black is about 30 nm.

[0099] (2) The slurry was uniformly coated on a porous aluminum foil with a total mass of 0.2 g and a size of 4 cm × 4 cm, and dried at 35°C to form a carbon film. The slurry was then cold-pressed on a roller mill to closely fit the porous aluminum foil and the carbon film, thereby preparing a self-heating material.

[0100] Among them, the total mass of the carbon film is 0.08 g; the cold pressing pressure is 8 MPa, the thickness of the porous aluminum foil is 0.05 mm, and the porosity is 20%.

[0101] (3) At room temperature of 26°C, the self-heating material was placed in a glass chromatographic bottle with a mouth diameter of 8 mm, a volume of 4 mL, and a bottle cap. The bottle cap was perforated to allow the insertion of an ultrafine thermocouple. 1 mL of 6 mol / L KOH was dripped into the pores of the aluminum foil in the self-heating material using a syringe, and the bottle cap was screwed on and the thermocouple wire was inserted. The thermocouple was connected to a temperature sensor to record temperature changes in real time.

[0102] The self-heating material prepared in Example 1 can reach 50° C. in 8 s, the instantaneous maximum temperature within 10 s is 87.3° C., and can be maintained above 50° C. for 66 s.

[0103] Example 2

[0104] It is basically the same as Example 1, except that the porous aluminum foil is replaced with an aluminum mesh of equal size and mass, and the porosity of the aluminum mesh is 20%.

[0105] The self-heating material prepared in Example 2 can reach 50° C. in 9 s, with an instantaneous maximum temperature of 106.7° C., and can be maintained above 50° C. for 82 s.

[0106] Example 3

[0107] The method is basically the same as Example 1, except that the solvent is replaced by water in an equal volume from N-methylpyrrolidone.

[0108] The self-heating material prepared in Example 3 can reach 50° C. in 13 s, with an instantaneous maximum temperature of 91.5° C., and can be maintained above 50° C. for 62 s.

[0109] Example 4

[0110] The method is basically the same as Example 2, except that the solvent is replaced by water in an equal volume from N-methylpyrrolidone.

[0111] The self-heating material prepared in Example 4 can reach 50° C. in 13 s, with an instantaneous maximum temperature of 99.7° C., and can be maintained above 50° C. for 70 s.

[0112] Example 5

[0113] The method is basically the same as Example 1, except that the porous aluminum foil is replaced with a porous aluminum-magnesium alloy foil of equal size and mass. The mass ratio of aluminum to magnesium in the aluminum-magnesium alloy is 9:1.

[0114] The self-heating material prepared in Example 5 can reach 50° C. in 11 s, with an instantaneous maximum temperature of 65.9° C., and can be maintained above 50° C. for 40 s.

[0115] Example 6

[0116] The method is basically the same as Example 2, except that the aluminum mesh is replaced with an aluminum-magnesium alloy mesh of equal size and mass. The mass ratio of aluminum to magnesium in the aluminum-magnesium alloy is 9:1.

[0117] The self-heating material prepared in Example 6 can reach 50° C. in 11 s, with an instantaneous maximum temperature of 72.2° C., and can be maintained above 50° C. for 46 s.

[0118] Example 7

[0119] The method is basically the same as Example 1, except that the porous aluminum foil is replaced with a porous aluminum-zinc alloy foil of equal size and mass. The mass ratio of aluminum to zinc in the aluminum-magnesium alloy is 9:1.

[0120] The self-heating material prepared in Example 7 can reach 50°C in 9 s, with an instantaneous maximum temperature of 92.5°C, and can be maintained above 50°C for 74 s.

[0121] Example 8

[0122] The method is basically the same as Example 2, except that the aluminum mesh is replaced with an aluminum-zinc alloy mesh of equal size and mass. The mass ratio of aluminum to zinc in the aluminum-magnesium alloy is 9:1.

[0123] The self-heating material prepared in Example 8 can reach 50° C. in 9 s, with an instantaneous maximum temperature of 101.4° C., and can be maintained above 50° C. for 80 s.

[0124] Example 9

[0125] It is basically the same as Example 1, except that the raw materials for preparing the positive electrode material layer are replaced by 50wt% activated carbon, 30wt% acetylene black and 20wt% binder polytetrafluoroethylene into 40wt% activated carbon, 30wt% acetylene black, 20wt% polytetrafluoroethylene and 10wt% manganese dioxide.

[0126] The self-heating material prepared in Example 9 can reach 50°C in 6 s, with an instantaneous maximum temperature of 115.8°C, and can be maintained above 50°C for 86 s.

[0127] Example 10

[0128] It is basically the same as Example 2, except that the raw materials for preparing the positive electrode material layer are replaced by 50wt% activated carbon, 30wt% acetylene black and 20wt% binder polytetrafluoroethylene into 40wt% activated carbon, 30wt% acetylene black, 20wt% polytetrafluoroethylene and 10wt% manganese dioxide.

[0129] The self-heating material prepared in Example 10 can reach 50° C. in 6 s, with an instantaneous maximum temperature of 132.2° C., and can be maintained above 50° C. for 91 s.

[0130] Embodiment 11

[0131] It is basically the same as Example 1, except that the particle size of the activated carbon is different; specifically, the particle size of the activated carbon is 200 mesh.

[0132] Example 12

[0133] It is basically the same as Example 1, except that the particle size of the activated carbon is different; specifically, the particle size of the activated carbon is 400 mesh.

[0134] Comparative Example 1

[0135] Mix 0.6 g of aluminum powder with a particle size of 400 mesh and 0.3 g of activated carbon powder with a particle size of 325 mesh, place the mixture in a glass chromatographic bottle, add 1 mL of KOH with a concentration of 6 mol / L into the glass chromatographic bottle with a syringe, screw on the bottle cap and insert the thermocouple wire; connect the thermocouple to the temperature sensor to record the temperature changes in real time.

[0136] The mixture of Comparative Example 1 reacted violently after contacting with KOH, and a sharp temperature rise was detected in the glass bottle, with the highest temperature reaching 259.1° C. within 5 s.

[0137] Comparative Example 2

[0138] A porous aluminum foil with a thickness of 0.05 mm and a porosity of 20% was placed in a glass chromatographic bottle. 1 mL of 6 mol / L KOH was added to the glass chromatographic bottle using a syringe. The bottle cap was screwed on and a thermocouple wire was inserted. The thermocouple was connected to a temperature sensor to record temperature changes in real time.

[0139] When the porous aluminum foil of Comparative Example 2 reacted with KOH, bubbles were generated without a sharp temperature rise, and the highest temperature was only 34.5°C.

[0140] Comparative Example 3

[0141] The method is basically the same as Example 1, except that the porosity of the porous aluminum foil is 10%.

[0142] Some raw material parameters of the self-heating materials in the above-mentioned Examples 1-11 and Comparative Examples 1-2 are shown in Table 1, and the heating performance results of the self-heating materials are shown in Table 2.

[0143] Table 1

[0144]

[0145] Table 2

[0146]

[0147] It can be seen from Table 1 and Table 2 that the self-heating material prepared in each embodiment of the present application can reach a maximum heating temperature of 65.9°C to 115.8°C after contacting with an alkaline electrolyte, and can be heated to 50°C within 6s to 13s, and can be maintained at a temperature above 50°C for more than 40s. It can be seen that the self-heating material of the present application has the advantages of rapid heating, controllable temperature, and long-lasting heating time; whether it can be promoted and applied in the field of heated cigarettes.

[0148] In Comparative Example 1, the powdered aluminum powder and powdered activated carbon powder react violently and heat up rapidly after contacting the alkaline electrolyte solution, with the highest temperature reaching 259.1°C, which poses certain safety risks.

[0149] Comparative Example 2 does not include a positive electrode material layer, and the alkaline electrolyte is in direct contact with the porous aluminum foil. The maximum temperature is only 34.5° C., and the purpose of heating cannot be achieved.

[0150] In Comparative Example 3, the porosity of the negative electrode material layer is only 10%, the alkaline electrolyte cannot fully contact the positive electrode material layer and the negative electrode material layer, the temperature rises slowly, and the maximum temperature that can be reached is limited.

[0151] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0152] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A self-heating material, characterized in that: It includes a positive electrode material layer and a negative electrode material layer, the positive electrode material layer and the negative electrode material layer are bonded to each other; the positive electrode material layer includes a carbon-based material; the porosity of the negative electrode material layer is 20% to 50%; and the negative electrode material layer includes a porous metal material.

2. The self-heating material according to claim 1, characterized in that: The mass ratio of the negative electrode material layer to the positive electrode material layer is 1:(0.3-0.5).

3. The self-heating material according to claim 1, characterized in that: The porous metal material includes one or more of a metal mesh, a porous metal plate, a porous metal foil and a porous metal belt.

4. The self-heating material according to claim 3, characterized in that: The porous metal material includes one or more of aluminum, magnesium, zinc and iron.

5. The self-heating material according to any one of claims 1 to 4, characterized in that: The carbon-based material includes one or more of activated carbon, graphite, expanded graphite, carbon nanotubes, graphene, conductive carbon black and acetylene black.

6. The self-heating material according to claim 5, characterized in that: The particle size of the activated carbon is 200-400 mesh.

7. The self-heating material according to any one of claims 1 to 4 and 6, characterized in that: The positive electrode material layer further includes one or more of a catalyst and a binder; Optionally, the catalyst includes one or more of noble metals and alloys thereof, transition metal oxides, transition metal sulfides, functionalized carbon materials and metal nitrides; Optionally, the binder includes one or more of polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl alcohol and potassium polyacrylate.

8. A method for preparing the self-heating material according to any one of claims 1 to 7, characterized in that: The steps include: Mixing the carbon-based material with a solvent to prepare a positive electrode slurry; The positive electrode slurry is coated on the negative electrode material layer, and the self-heating material is obtained by drying and cold pressing.

9. The method for preparing the self-heating material according to claim 8, characterized in that: The preparation method meets at least one of the following characteristics: (1) The drying temperature is 25°C to 40°C; (2) The cold pressing pressure is 5 MPa to 15 MPa.

10. A self-heating component, characterized in that: It comprises an alkaline electrolyte and the self-heating material according to any one of claims 1 to 7, wherein the alkaline electrolyte is placed separately from the self-heating material.

11. The self-heating component according to claim 10, characterized in that: The alkaline electrolyte includes one or more of potassium hydroxide and its hydrate, sodium hydroxide and its hydrate, lithium hydroxide and its hydrate, calcium hydroxide and its hydrate, potassium carbonate and its hydrate, sodium carbonate and its hydrate, lithium carbonate and its hydrate, calcium carbonate and its hydrate, potassium bicarbonate and its hydrate, sodium bicarbonate and its hydrate, lithium bicarbonate and its hydrate, and calcium bicarbonate and its hydrate.

12. A self-heating device, characterized in that: A self-heating component comprising any one of claims 10 to 11.

13. The application method of the self-heating device according to claim 12, characterized in that: An alkaline electrolyte is brought into contact with the self-heating material.

14. A heated cigarette smoke-generating body, characterized in that: It comprises an aerosol matrix, cigarette paper and the self-heating material according to any one of claims 1 to 7; the cigarette paper is wrapped around the outside of the aerosol matrix, and the self-heating material is located between the aerosol matrix and the cigarette paper.

15. A heated cigarette, characterized in that: It includes the heated cigarette smoke-generating body as described in claim 14.

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