Composite electrode material, method for preparing the same, and battery

Abstract

The application discloses a composite electrode material and a preparation method and a battery thereof, and relates to the technical field of batteries, and aims at solving the problems of unsatisfactory sodium storage capacity and high cost of a sodium battery negative electrode material. The preparation method of the composite electrode material comprises the following steps: providing a carbon paper precursor through wet forming; immersing the carbon paper precursor in a tungsten disulfide precursor dispersion solution to obtain a carbon paper precursor immersion; performing heat pressing and solidification and carbonization on the carbon paper precursor immersion to obtain a composite electrode material semi-finished product; and performing vulcanization on the composite electrode material semi-finished product to obtain a composite electrode material containing tungsten disulfide. The composite electrode material is prepared by the preparation method of the composite electrode material; and the battery comprises the composite electrode material. The application discloses a composite electrode material and a preparation method and a battery thereof, and is used for preparing the composite electrode material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a composite electrode material, a preparation method thereof and a battery. BACKGROUND

[0002] Sodium-ion batteries have abundant resource reserves and low extraction cost, and sodium and lithium are in the same main group and have similar physicochemical properties, so they become potential substitutes for lithium-ion batteries. However, the sodium ion radius is much larger than the lithium ion radius, and it is more difficult to deintercalate in the electrode material. Even if it is successfully deintercalated from the electrode material, it will cause deformation of the carbon skeleton, reducing the mechanical properties of the battery.

[0003] In order to overcome this defect, the most commonly used negative electrode material at present is hard carbon negative electrode material. However, the sodium storage capacity of hard carbon negative electrode material is not ideal, and the cost is relatively high. Therefore, it is very crucial to prepare an electrode material with high sodium storage capacity and low cost. SUMMARY

[0004] The purpose of the present application is to provide a composite electrode material, a preparation method thereof and a battery, so as to ensure that the composite electrode material has high sodium storage capacity and low cost.

[0005] In order to achieve the above purpose, the present application provides a preparation method of a composite electrode material, comprising:

[0006] A wet-formed carbon paper precursor is provided;

[0007] The carbon paper precursor is immersed in a tungsten disulfide precursor dispersion solution to obtain a carbon paper precursor immersion product;

[0008] The carbon paper precursor immersion product is subjected to heat pressing and curing and carbonization operations to obtain a composite electrode material semi-finished product;

[0009] The composite electrode material semi-finished product is subjected to vulcanization to obtain a composite electrode material containing tungsten disulfide.

[0010] Compared with the prior art, in the preparation method of the composite electrode material provided by the present application, the carbon paper precursor is first immersed in the tungsten disulfide precursor dispersion liquid, and the carbon paper precursor immersion is heat-pressed and cured before carbonization operation, so that the tungsten disulfide precursor can fully contact with the fibers in the carbon paper precursor under the action of heat pressing before the carbon paper precursor is converted into carbon paper. Based on this, after heat pressing and curing, the carbonization operation and sulfurization of the carbon paper precursor immersion can ensure that the carbon fibers in the formed composite electrode material have good composite effect with the tungsten disulfide. Moreover, in the preparation method provided by the present application, the carbon paper precursor is immersed in the tungsten disulfide precursor dispersion liquid before the carbon paper is formed, and then heat-pressed and cured, carbonized and sulfurized, so that the composite process of the carbon paper and the tungsten disulfide is synchronized with the manufacturing process of the carbon paper, avoiding the complicated problem caused by coating the tungsten disulfide after the carbon paper is formed, and reducing the production cost. In addition, because the carbon paper can be mass-produced by using the wet forming method, the production cost is further reduced.

[0011] In addition, in the composite material prepared by the preparation method provided by the present application, the carbon paper itself has a porous structure, which can provide a sodium ion diffusion channel, improve the charge transfer efficiency, accommodate the volume expansion in the charging and discharging process, improve the safety, and in addition, the carbon paper itself can also act as a current collector in sodium ions, reducing the cost of setting a current collector in a sodium ion battery, and through the composite with the tungsten disulfide having a two-dimensional layered structure, a high rate performance and a high sodium storage capacity can be achieved.

[0012] In the second aspect provided by the present application, the present application further provides a composite electrode material, which is prepared by the preparation method of the composite electrode material.

[0013] In the third aspect provided by the present application, the present application further provides a battery comprising the composite electrode material.

[0014] Compared with the prior art, the composite electrode material and the battery provided by the present application have the same beneficial effects as the preparation method of the composite electrode material of the first aspect, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0015] The drawings described herein are used to provide further understanding of the present application, and form a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0016] Figure 1 A preparation flow chart of the composite electrode material provided by the present embodiment is shown;

[0017] Figure 2 A structure schematic diagram of the battery provided by the present embodiment is shown.

[0018] Reference signs:

[0019] 200-battery, 201-separator, 202a-positive current collector, 202b-positive material, 203a-carbon paper, 203b-negative material. DETAILED DESCRIPTION

[0020] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects clearer, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and not used to limit the present application.

[0021] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited. The meaning of "several" is one or more, unless otherwise explicitly and specifically limited.

[0022] At present, due to the fact that the radius of sodium ion is much larger than that of lithium ion, it is difficult to deintercalate in the electrode material, and even if it is successfully deintercalated from the electrode material, it will also cause the deformation of the carbon skeleton, resulting in the reduction of the mechanical properties of the battery. In order to overcome this defect, hard carbon is often used as the negative material on the market, but its sodium storage capacity is not ideal, and the cost is relatively high.

[0023] In view of the above problems, the preparation method of the composite electrode material provided by the embodiments of the present application can prepare a hard carbon composite electrode material with high sodium storage capacity and low cost. Figure 1 The preparation flow chart of the composite electrode material provided by the embodiments of the present application is shown. As shown in the figure, the preparation method of the composite electrode material comprises: Figure 1

[0024] Step 101: providing a wet-formed carbon paper precursor.

[0025] For example, the carbon paper precursor in the embodiments of the present application is obtained by the technical means of wet forming. In this technical means, carbon fibers and paper-based fibers are first stirred in a solution at a speed of 500 rpm to 1000 rpm for more than 10 minutes, so that the fibers are fully dispersed, then the fully dispersed fibers are made into paper to form a wet paper web, and finally the carbon paper precursor to be obtained in the embodiments of the present application is obtained after drying at 90 to 110 DEG C for 30 to 40 minutes. In order to make the fibers interweave more fully, an organic compound containing a binder (such as polyvinyl alcohol, polyimide) and a cationic reinforcing agent (such as a surfactant) is usually added.​

[0026] Step 102: dipping the carbon paper precursor into the tungsten disulfide precursor dispersion to obtain a carbon paper precursor dip.

[0027] For example, the tungsten disulfide precursor dispersion contains tungsten powder and hydrogen peroxide solution, and the mass ratio of tungsten powder to hydrogen peroxide is 7:3. Under the condition of 25-40℃, take the tungsten powder after grinding and dissolve in the hydrogen peroxide solution at a ratio of (7-10):(3-5), at this time the tungsten powder can be completely dissolved in the hydrogen peroxide solution to prepare a tungsten suspension. Then add the stabilizer isopropyl alcohol to the tungsten suspension, use a magnetic stirrer to stir at a speed of 500-700 rpm for 30-90 min, and finally obtain the tungsten disulfide precursor dispersion after 1 h. Finally, dip the carbon paper precursor into the prepared tungsten disulfide precursor dispersion to obtain a carbon paper precursor dip. The isopropyl alcohol is analytical pure, and 10-20 mL of isopropyl alcohol is required per 30 mL of tungsten suspension.

[0028] For example, the carbon paper precursor has a basis weight of 80-90 g / m2. Within this range, both the cost and the strength, conductivity and weight of the formed carbon paper can meet the needs of sodium battery operation. When the basis weight of the carbon paper precursor is 90 g / m2, the carbon fibers are sufficient in number, so that the tungsten disulfide precursor can fully contact and load the tungsten disulfide precursor during the steps of dipping in the tungsten disulfide precursor dispersion and heat pressing and curing, thereby ensuring good composite effect of the carbon fibers and tungsten disulfide in the composite electrode material. More importantly, wet forming is the mainstream production technology for carbon paper at present, and can be used to mass-produce the composite electrode material provided in the embodiments, with good consistency, stability and low manufacturing cost.

[0029] Step 103: heat pressing and curing the carbon paper precursor dip to obtain a composite electrode material semi-product.

[0030] For example, the dried carbon paper precursor dip is first heat pressed and cured before carbonization, so that the tungsten disulfide precursor can fully contact the fibers in the carbon paper precursor under the action of heat pressing before the carbon paper precursor is converted into carbon paper. Therefore, the carbon paper precursor dip after heat pressing and curing can be carbonized to obtain good composite effect of the carbon fibers and the tungsten disulfide precursor.

[0031] Step 104: vulcanizing the composite electrode material semi-product to obtain a composite electrode material formed by tungsten disulfide and carbon paper.

[0032] Exemplarily, the obtained composite electrode material semi-finished product is immersed in thiourea, put into an alumina crucible, and sintered in a tube furnace filled with a protective gas to prevent the sulfidized composite electrode material semi-finished product from being affected by external gas at high temperature. After the above steps, the carbon fibers in the composite electrode material have a good composite effect with the tungsten disulfide, thereby ensuring that the composite electrode material has good electrical conductivity and physical properties applicable to the field of fuel cells. Moreover, in the preparation method provided in the embodiment of the present application, the carbon paper and the tungsten disulfide are simultaneously compounded during the manufacturing process of the carbon paper, thereby avoiding the complicated problem caused by coating the tungsten disulfide on the carbon paper after the carbon paper is formed, and reducing the production cost.

[0033] In an alternative way, the carbon paper precursor comprises carbon fiber raw materials, a binder, and ethylene oxide and a surfactant.

[0034] Exemplarily, the carbon fiber raw materials are composed of carbon fibers and paper-based fibers, and at least one of viscose fibers, cellulose nanofibrils, and carbon fibers. The carbon fibers are at least one of polyacrylonitrile-based carbon fibers and pitch-based carbon fibers, wherein the polyacrylonitrile-based carbon fibers have good structural and functional properties and high yield; the pitch-based carbon fibers have a carbon yield of more than 80% after carbonization, and thus are also good choices of carbon fiber types.

[0035] Exemplarily, the mass ratio of the viscose fibers, the carbon fibers, and the cellulose nanofibrils is (10-15):(83-88):(1-2) in terms of mass fraction. An appropriate amount of water is added at a speed of 500 rpm-1000 rpm, and the above carbon fiber raw materials are dispersed by stirring for more than 10 min. When the carbon fiber raw materials account for 0.1%-0.15% of the mass of the mixture of the carbon fiber raw materials and the water, the carbon fiber raw materials can be fully dispersed into single fibers, and the fiber agglomeration phenomenon is avoided. The length of the carbon fibers is 5 mm-6 mm, the length is 5-6 mm, and the resistivity is 0.001-0.1 Ω·cm. The length of the viscose fibers is 3 mm-5 mm. When the length of the viscose fibers is 3-4 mm, the filling effect is better, and the formed paper is more uniform.

[0036] Exemplarily, when the mass ratio of the polyethylene oxide, the surfactant, and the polyvinyl alcohol is 3:1:3, the dispersant and the polyvinyl alcohol make the carbon fiber raw materials interweave more fully at this ratio, thereby ensuring that the composite electrode material formed in the subsequent steps has good mechanical properties and electrical conductivity.

[0037] The surface active agent is exemplarily at least one of Tween-80, Turkey red oil and glyceryl oleate. The carbon fiber is hydrophobic, so that it is easy to agglomerate under the soaking of water and difficult to be uniformly dispersed, thus, it is necessary to add the surface active agent as a dispersant of the carbon fiber to promote its sufficient dispersion in water. In the step of impregnating the carbon paper precursor in the tungsten disulfide precursor dispersion liquid, since the surface active agent is used as a dispersant of the carbon fiber, it can be in sufficient contact with the tungsten disulfide precursor during the impregnation process, avoiding the phenomenon that only part of the carbon fiber is impregnated with the tungsten disulfide precursor dispersion liquid due to the agglomeration of the carbon fiber. Based on this, after the heat pressing and curing, the carbonization operation and the sulfuration of the carbon paper precursor impregnation can ensure that the carbon fiber and the tungsten disulfide in the formed composite electrode material have a good composite effect, and have good rate performance and sodium storage capacity. When the surface active agent is Tween-80, the addition amount is 0.02-0.05% of the mass of the carbon paper precursor before drying, and the dispersion effect is the best.

[0038] Exemplarily, the carbon paper precursor contains 10% by mass of polyvinyl alcohol for processing the paper. Since the carbon fiber is a fibrous structure of inorganic carbon material, it has high tensile strength and tensile modulus, but it is a brittle material and has poor toughness. Therefore, polyvinyl alcohol is needed to be used to improve the toughness of the carbon paper through its good strong adhesion, so as to ensure that the mechanical properties of the composite electrode material prepared in the subsequent steps are good, and the durability is also improved. When the polyvinyl alcohol with a molecular weight of 170-220 thousand is selected, and the addition amount is 0.1-0.15% of the mass of the carbon paper precursor before drying, the effect of improving the toughness of the carbon paper is the best.

[0039] Exemplarily, the carbon paper precursor contains polyethylene oxide with a molecular weight of 6-8 million, and the addition amount is 0.1-0.2% of the mass of the carbon paper precursor before drying. The polyethylene oxide is a water-soluble resin, which can act as a dispersant together with the surface active agent to improve the dispersion effect of the carbon paper precursor. The polyethylene oxide, the surface active agent and the polyvinyl alcohol contained in the carbon paper precursor synergistically interweave the carbon fiber raw materials more fully, so as to ensure that the composite electrode material formed in the subsequent steps has good mechanical properties and electrical conductivity.

[0040] In an alternative way, the reaction temperature of the heat pressing and curing is 130-150°C, the reaction pressure is 10-15 MPa, and the reaction time is 40-50 min; the reaction temperature of the carbonization is 1400-1500°C, the heating rate is 25-35°C / min, and the reaction time is 7-9 h.

[0041] Exemplarily, the carbon paper precursor dip is placed in a flat vulcanizing machine, and hot-pressed at 130-150 DEG C, 10-15 MPa for 40-50 min, so that the gas impurities in the carbon fiber can be discharged in time, the dipped tungsten disulfide precursor can better contact and fill into the gap of the carbon fiber, and the density of the composite electrode material semi-finished product after extrusion can be significantly improved, thereby improving the performance of the composite material. Then, the carbon paper is heat-treated at 1400-1500 DEG C, 25-35 DEG C / min under a protective gas (such as nitrogen) for 7-9 h using a vacuum tube furnace, which significantly improves the carbon content in the composite electrode material semi-finished product, so that the composite electrode material semi-finished product has good electrical conductivity and mechanical properties.

[0042] The embodiment of the present application also provides a composite electrode material prepared by the preparation method of the composite electrode material.

[0043] Exemplarily, in the carbon paper provided in the embodiment of the present application, the carbon paper itself has a porous structure, can provide a sodium ion diffusion channel, improve the charge transfer efficiency, accommodate the volume expansion during the charging and discharging process, and improve the safety. In addition, the carbon paper itself can also act as a current collector in sodium ions, reducing the cost of setting a current collector in a sodium ion battery. In tungsten disulfide, the tungsten atoms and the sulfur atoms are connected by strong chemical bonds, and the sulfur atoms between the layers are connected by weak molecular bonds. The binding force between the layers is still van der Waals force, and the interlayer spacing is larger than that of molybdenum disulfide. The carbon fiber paper base is combined with tungsten disulfide having a two-dimensional layered structure, so that high rate performance and sodium storage capacity can be achieved.

[0044] The embodiment of the present application provides a battery which can include the composite electrode material provided by the embodiment of the present application to ensure that the composite electrode material has high sodium storage capacity and low cost. It should be understood that the electrode material can be defined as a negative electrode material, and the carbon paper in the negative electrode material can act as a current collector of the negative electrode of the ion battery. The ion battery can also include a positive electrode material, a positive electrode current collector, a separator and an electrolyte. The separator can have opposite first and second surfaces, the positive electrode material is located between the positive electrode current collector and the first surface, and the negative electrode material is located between the carbon paper and the second surface. Figure 2 The structure diagram of the battery of the embodiment of the present application is shown in FIG. 2. Figure 2 As shown in FIG. 2, the battery 200 of the embodiment of the present application includes a separator 201, a positive electrode current collector 202a, a positive electrode material 202b, a negative electrode material 203b and a carbon paper 203a distributed on both sides of the separator 201.

[0045] The present application will be further described below in conjunction with the embodiments.

[0046] Embodiment one

[0047] The preparation method of the composite electrode material provided by the embodiment of the present application comprises the following steps:

[0048] Firstly, a carbon paper precursor is prepared: 10 parts of viscose fibers with a length of 3 mm, 2 parts of cellulose nanofibrils, and 88 parts of polyacrylonitrile-based carbon fibers with a length of 6 mm and a resistivity of 10 mΩ / cm are weighed, and then the above-mentioned carbon fiber raw materials are added into a dispersion barrel with a stirrer, 568 parts of water is added to make the total mass fraction of the viscose fibers, cellulose nanofibrils and polyacrylonitrile-based carbon fibers 0.15%, and stirring is started at a speed of 700 rpm. 0.04wt% of Tween-80 is first added, and then 0.12wt% of polyethylene oxide (with a molecular weight of 6 million) is added. After the carbon fiber raw materials are completely dispersed into single fibers, 0.12wt% of polyvinyl alcohol solution (with a molecular weight of 220,000 and a concentration of 10%) is added. After mechanical stirring for 10 min, a wet paper web is formed by a wet forming device, and then the wet paper web is dried in an oven at 110℃ for 30 min to obtain a carbon paper precursor with a basis weight of 90 g / m2.

[0049] Secondly, a carbon paper precursor impregnant is prepared: 1.5 g of tungsten powder is ground and dissolved in 30 mL of a 30wt% hydrogen peroxide solution, and the temperature is kept at 35℃. After 1 h of reaction, a tungsten peroxide suspension is generated. Then 15 mL of analytical grade isopropyl alcohol is added to the tungsten peroxide suspension, and a magnetic stirrer is used to stir at a speed of 600 r / min for 60 min to obtain a tungsten disulfide precursor dispersion liquid. Finally, the carbon paper precursor is immersed in the tungsten disulfide precursor dispersion liquid, and ultrasonic equipment is used to assist in ultrasonic treatment for 1 min. After being taken out and dried, a carbon paper precursor impregnant is obtained.

[0050] Thirdly, a composite electrode material semi-finished product is prepared: the carbon paper precursor impregnant is placed in a flat vulcanizing machine and hot-pressed at a temperature of 140℃ and a pressure of 10 MPa for 45 min. Then, the carbon paper precursor impregnant is heat-treated in a vacuum tube furnace under the protection of nitrogen at a temperature of 1500℃ and a rate of 30℃ / min for 8 h to obtain a composite electrode material semi-finished product.

[0051] Fourthly, a composite electrode material is prepared: the composite electrode material semi-finished product is immersed in thiourea and sintered in an alumina crucible in a tube furnace under the protection of argon to obtain a composite electrode material.

[0052] Example Two

[0053] The preparation method of the composite electrode material provided by the embodiment of the present application comprises the following steps:

[0054] First step, preparation of carbon paper precursor: take 15 parts by mass of viscose fiber with a length of 3mm, 1 part by mass of cellulose nanofibril, 84 parts by mass of polyacrylonitrile-based carbon fiber with a length of 6mm and a resistivity of 10mΩ / cm, add the above carbon fiber raw materials to a dispersion barrel with a stirrer, add 570 parts of water to make the total mass fraction of viscose fiber, cellulose nanofibril and polyacrylonitrile-based carbon fiber 0.15%, start stirring at a speed of 700rpm, first add 0.04wt% of Tween-80, then add 0.10wt% of polyethylene oxide (molecular weight 6 million), after the carbon fiber raw materials are completely dispersed into single fibers, add 0.10wt% of polyvinyl alcohol solution (molecular weight 200,000, concentration 10%), after mechanical stirring for 10min, use a wet forming equipment to make a wet paper web, dry it in an oven at 90℃ for 40min to make a carbon paper precursor with a basis weight of 90g / m2.

[0055] Second step, preparation of carbon paper precursor impregnation: grind 2.0g of tungsten powder and dissolve it in 30ml of 30% hydrogen peroxide solution, keep the temperature at 35℃, and after 1h of reaction, generate a tungsten acid suspension. Then add 10ml of analytical pure isopropyl alcohol to the tungsten acid suspension, stir it with a magnetic stirrer at a speed of 600r / min for 60min to obtain a tungsten disulfide precursor dispersion liquid. Finally, immerse the carbon paper precursor in the tungsten disulfide precursor dispersion liquid, and use ultrasonic equipment to assist with ultrasonic immersion for 1min, take it out and dry it to obtain a carbon paper precursor impregnation.

[0056] Third step, preparation of composite electrode material semi-finished product: place the carbon paper precursor impregnation in a flat vulcanizing machine, heat press at 150℃ and 15MPa for 40min, then use a vacuum tube furnace to heat treat the carbon paper precursor impregnation at 1500℃ and a rate of 35℃ / min for 8h under nitrogen protection to obtain a composite electrode material semi-finished product.

[0057] Fourth step, preparation of composite electrode material: immerse the composite electrode material semi-finished product in thiourea, place it in an alumina crucible, and sinter it in a tube furnace under argon protection to obtain a composite electrode material.

[0058] Example three

[0059] The preparation method of the composite electrode material provided by the embodiment of the present application comprises the following steps:

[0060] First step, preparation of carbon paper precursor: take 10 parts by mass of viscose fiber, 2 parts by mass of cellulose nanofibril, 88 parts by mass of pitch-based carbon fiber with a length of 6 mm and a resistivity of 6 mΩ / cm, add the above carbon fiber raw materials to a dispersion barrel with a stirrer, add 600 parts of water to make the total mass fraction of viscose fiber, cellulose nanofibril and polyacrylonitrile-based carbon fiber 0.10%, start stirring at a speed of 700 rpm, first add 0.05wt% of Turkish red oil, then add 0.20wt% of polyethylene oxide (molecular weight 7 million), after the carbon fiber raw materials are completely dispersed into single fibers, add 0.15wt% of polyvinyl alcohol solution (molecular weight 220,000, concentration 10%), after mechanical stirring for 10 min, use a wet forming equipment to make a wet paper web, dry it in an oven at 90℃ for 40 min to make a carbon paper precursor with a basis weight of 80g / m2.

[0061] Second step, preparation of carbon paper precursor impregnant: grind 2.5g of tungsten powder and dissolve it in 30ml of 30% hydrogen peroxide solution, keep the temperature at 35℃, and after 1h of reaction, generate a tungsten acid suspension. Then add 20ml of analytical pure isopropyl alcohol to the tungsten acid suspension, and use a magnetic stirrer to stir at a speed of 700r / min for 40min to obtain a tungsten disulfide precursor dispersion. Finally, immerse the carbon paper precursor in the tungsten disulfide precursor dispersion, and use ultrasonic equipment to assist with ultrasonic, immerse for 1min, take out and dry to obtain a carbon paper precursor impregnant.

[0062] Third step, preparation of composite electrode material semi-finished product: place the carbon paper precursor impregnant in a flat vulcanizing machine, heat press at 130℃ and 10MPa for 50min, then use a vacuum tube furnace to heat treat the carbon paper precursor impregnant at 1400℃ and a rate of 35℃ / min under nitrogen protection for 9h to obtain a composite electrode material semi-finished product.

[0063] Fourth step, preparation of composite electrode material: immerse the composite electrode material semi-finished product in thiourea, place it in an alumina crucible, and sinter it in a tube furnace under argon protection to obtain a composite electrode material.

[0064] Example four

[0065] The preparation method of the composite electrode material provided by the embodiment of the present application comprises the following steps:

[0066] The first step is to prepare the carbon paper precursor: take 15 parts by mass of viscose fibers with a length of 3 mm, 2 parts by mass of cellulose nanofibrils, 44 parts by mass of pitch-based carbon fibers with a length of 6 mm and a resistivity of 6 mΩ / cm, and 44 parts by mass of polyacrylonitrile-based carbon fibers with a length of 6 mm and a resistivity of 6 mΩ / cm, and add the above carbon fiber raw materials to a dispersion barrel with a stirrer. Add 800 parts of water to make the total mass fraction of viscose fibers, cellulose nanofibrils, and polyacrylonitrile-based carbon fibers 0.15%, start stirring at a speed of 700 rpm, first add 0.02wt% of oleic acid glyceride, then add 0.12wt% of polyethylene oxide (molecular weight 800 million), and then add 0.15wt% of polyvinyl alcohol solution (molecular weight 170,000, concentration 10%). After mechanical stirring for 10 minutes, a wet paper web is formed by a wet forming device, and dried in an oven at 100°C for 35 minutes to form a carbon paper precursor with a basis weight of 85g / m2.

[0067] The second step is to prepare the carbon paper precursor impregnant: grind 3.0g of tungsten powder and dissolve it in 30ml of 30% hydrogen peroxide solution, keeping the temperature at 35°C. After 1h of reaction, a tungsten peroxide suspension is formed. Then add 20ml of analytical pure isopropyl alcohol to the tungsten peroxide suspension, and stir at a speed of 700rpm / min for 40min using a magnetic stirrer to obtain a tungsten disulfide precursor dispersion. Finally, immerse the carbon paper precursor in the tungsten disulfide precursor dispersion and use ultrasonic equipment to assist with ultrasonic treatment for 1min. After drying, the carbon paper precursor impregnant is obtained.

[0068] The third step is to prepare the composite electrode material semi-finished product: place the carbon paper precursor impregnant in a flat vulcanizing machine and heat press at 140°C and 10MPa for 50min. Then use a vacuum tube furnace to heat treat the carbon paper precursor impregnant at 1500°C and a rate of 30°C / min for 7h under nitrogen protection to obtain a composite electrode material semi-finished product.

[0069] The fourth step is to prepare the composite electrode material: immerse the composite electrode material semi-finished product in thiourea and place it in an alumina crucible for sintering in a tube furnace under argon protection to obtain the composite electrode material.

[0070] The above description is merely a specific implementation of the application, obviously, various modifications and combinations can be made to it without departing from the spirit and scope of the application. Accordingly, the specification and drawings are merely illustrative of the exemplary embodiments of the application, and any and all modifications, variations or equivalents that fall within the scope of the application should be considered covered by the application. Obviously, those skilled in the art can make various modifications and variations to the application without departing from the spirit and scope of the application. Thus, if these modifications and variations of the application fall within the scope of the claims of the application and their equivalent technologies, the intention of the application includes these modifications and variations. Any skilled person in the art can easily think of changes or replacements within the technical scope disclosed by the application, which should be covered by the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A method for preparing a composite electrode material, characterized by, The application relates to a preparation method of a composite electrode material. The application provides a wet-formed carbon paper precursor; The carbon paper precursor comprises carbon fiber raw materials, polyvinyl alcohol, polyethylene oxide and a surfactant, the carbon fiber raw materials comprise at least one of viscose fibers, cellulose nanofibrils and carbon fibers, the molecular weight of the polyethylene oxide is 6-8 million, and the mass ratio of the polyethylene oxide, the surfactant and the polyvinyl alcohol is (2-3):(0.8-1):(2-3); The carbon paper precursor is immersed in a tungsten disulfide precursor dispersion solution to obtain a carbon paper precursor immersion object; The carbon paper precursor is subjected to heat pressing and curing and carbonization to obtain a composite electrode material semi-finished product; The composite electrode material semi-finished product is vulcanized to obtain a composite electrode material formed by tungsten disulfide and carbon paper; the quantitative value of the carbon paper precursor is 80-90 g / m2; the tungsten disulfide precursor dispersion solution contains tungsten powder and a hydrogen peroxide solution, and the mass ratio of the tungsten powder to the hydrogen peroxide is (7-10):(3-5); the heating rate of the carbonization is 25-35 DEG C / min, and the reaction time of the carbonization is 7-9 h.

2. The method of claim 1, wherein the composite electrode material is prepared by a process comprising: The carbon fiber is at least one of polyacrylonitrile-based carbon fiber and pitch-based carbon fiber, the length of the carbon fiber is 5-6 mm, and the length of the viscose fiber is 3-5 mm.

3. The method of claim 1, wherein the composite electrode material is prepared by a process comprising: According to mass fraction, the mass ratio of the viscose fiber, the carbon fiber and the cellulose nanofibrils is (10-15):(83-88):(1-2).

4. The method of claim 1, wherein the composite electrode material is prepared by a process comprising: The surfactant is at least one of Tween-80, Turkish red oil and glyceryl oleate.

5. The preparation method of the composite electrode material according to any one of claims 1-4. The reaction temperature of the heat pressing and curing is 130-150 DEG C, the reaction pressure is 10-15 MPa, and the reaction time is 40-50 min; and the reaction temperature of the carbonization is 1400-1500 DEG C.

6. A composite electrode material, characterized by The composite electrode material is prepared by the preparation method of the composite electrode material according to any one of claims 1-5.

7. A battery, characterized by The application further provides the composite electrode material.

Images