Preparation method of ant nest-like carbon material and zinc-iodine soft pack battery

Abstract

This invention belongs to the field of aqueous battery technology and discloses a method for preparing ant-nest carbon material and a zinc-iodine soft-pack battery. The preparation method includes: (1) preparing ZIF-8 material with zinc nitrate hexahydrate and 2-methylimidazole; (2) calcining the material obtained in step (1) to obtain ant-nest carbon material; the zinc-iodine soft-pack battery includes a zinc foil negative electrode, an ant-nest carbon material positive electrode, a glass fiber separator and an electrolyte; the ant-nest carbon material obtained by this invention has a high specific surface area and abundant pore structure, which can effectively carry and restrict iodine active substances and improve the effective utilization rate of iodine; it can restrict the dissolution and diffusion of intermediate polyiodide ions and suppress the shuttle effect; and it is inexpensive, easy to prepare and highly reproducible; when matched with zinc foil to form a zinc-iodine soft-pack battery, using an aqueous electrolyte and a graphite paper current collector, it is not easy to cause dangerous situations such as combustion or explosion. At the same time, the application of graphite paper current collector shows a trend of increasing energy density.

Description

Technical Field

[0001] This invention relates to the field of aqueous battery technology, and in particular to a method for preparing an ant-nest-like carbon material and a zinc-iodine soft-pack battery. Background Technology

[0002] With the rapid development of portable electronic devices, electric vehicles, and energy storage systems, higher demands are being placed on the energy density and safety of batteries. Zinc-iodine batteries have attracted widespread attention due to their high theoretical specific capacity, high safety, ideal redox potential, abundant resource reserves, and low cost.

[0003] However, zinc-iodine batteries still suffer from problems such as poor conductivity due to iodine deficiency and the polyiodine ion shuttle effect. The key lies in the effective adsorption and fixation of iodine by the cathode material. To address these issues, researchers have developed various iodine support materials, among which carbon materials have become ideal candidates due to their high conductivity, strong plasticity, and ease of availability. Although significant progress has been made in the research of zinc-iodine battery support materials, some problems remain to be solved, such as the difficulty in increasing the iodine loading capacity and the relatively low actual capacity. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing ant-nest-like carbon material and a zinc-iodine soft-pack battery, so as to solve the problems of low iodine loading in the positive electrode material of zinc-iodine batteries and the difficulty in improving the safety and energy density of existing soft-pack batteries.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing an ant-nest-like carbon material, the method comprising:

[0007] (1) Zinc salt and organic ligand are mixed in a solvent and reacted at room temperature by stirring or standing to synthesize ZIF-8;

[0008] (2) The ZIF-8 prepared in step (1) is calcined at high temperature and under an argon atmosphere to obtain ant nest carbon material.

[0009] Furthermore, the zinc salt is zinc nitrate hexahydrate; the organic ligand is 2-methylimidazole; the solvent includes water and methanol; and the room temperature is 25 degrees Celsius.

[0010] Furthermore, in step (1), the zinc salt is 1-4 moles; the organic ligand is 4-8 moles; and the solvent volume is 200-500 ml.

[0011] Further, the zinc salt and organic ligand in the molar ratio of 1:4 mentioned in step (1) were added to 200-500 mL of methanol, and stirred at 500-1000 rpm for 8-12 hours at room temperature. The prepared product was filtered and collected, washed 3-5 times with methanol, and freeze-dried overnight to finally obtain ZIF-8 powder.

[0012] Further, in step (2), the ZIF-8 prepared in step (1) is heated to 900-1000 degrees Celsius at a heating rate of 2-3 degrees Celsius / minute under an argon atmosphere and calcined for 1-4 hours to obtain an ant-nest-like carbon material. Suitable calcination temperature and time result in a better pore structure in the material, which is beneficial for iodine storage in zinc-iodine batteries.

[0013] More preferably, in step (2), the heating rate is 3 degrees Celsius / minute, and the temperature is raised to 950 degrees Celsius;

[0014] Furthermore, a zinc-iodine soft-pack battery is prepared by means of the following steps.

[0015] Step (1): Take the above-mentioned ant nest carbon material with a mass ratio of (1:1)-(1:1.5) and mix it with iodine in a high-pressure reactor. React it in a forced-air drying oven at 100-140 degrees Celsius for 2-6 hours for iodine sealing. After the reaction is completed, take the powder and dry it at 130 degrees Celsius for 1 hour to remove residual iodine on the surface, thus obtaining the iodine-sealed ant nest carbon material. The formula for calculating the iodine loading of the material is: Iodine loading = (mass of iodine-sealed ant nest carbon material - mass of initial ant nest carbon material) / (mass of initial ant nest carbon material + mass of iodine);

[0016] Step (2): Solvent LA133 water-based adhesive and deionized water at a mass ratio of 3:97, and stir at high speed for 1-2 hours to make adhesive solution 1. The stirring speed is 800 rpm.

[0017] Step (3): Mix and grind the superconducting carbon black and the ant nest carbon material sealed with iodine evenly and add it to the prepared adhesive liquid 1 above. Stir at high speed for 1-2 hours to obtain mixture 1. The stirring speed is 1500 rpm.

[0018] Step (4): By adding an appropriate amount of deionized water, adjust the viscosity of mixture 1 to 1500-2000 MPa.S and the fineness to 15 μm to obtain zinc-iodine battery positive electrode slurry;

[0019] Step (5): The zinc-iodine battery positive electrode slurry is evenly coated onto the cut graphite paper current collector and dried. After coating, the zinc-iodine battery positive electrode sheet is obtained. The electrode sheet is 60mm wide and 70mm long, and the iodine content is 20-30mg.

[0020] Step (6): The positive electrode sheet and negative zinc sheet of the zinc-iodine battery are wound with the glass fiber separator in a positive-negative opposite manner to form a soft-pack battery cell, and the core is covered with adhesive tape.

[0021] Step (7): Assemble with the pre-stamped and cut aluminum-plastic film to a specified depth, and seal the top and sides to form an unfilled soft-pack battery cell;

[0022] Step (8): Inject 1.3 ml of electrolyte containing 2 moles of zinc sulfate and 0.05 moles of potassium iodide into the unfilled soft-pack cell, and pre-seal the top side to form an electrolyte-filled soft-pack battery;

[0023] Step (9): Allow the injected soft-pack battery to stand until the electrolyte is fully absorbed, thus forming a zinc-iodine soft-pack battery.

[0024] Furthermore, the mass ratio of the LA133 water-based adhesive in step (2) and the superconducting carbon black in step (3) to the ant nest carbon material sealed with iodine is 7:2:1.

[0025] Further, in step (7), the aluminum-plastic film is divided into two parts: an upper and lower tank area and an air bag area; the thickness of the aluminum-plastic film is 150 μm; the tank area is formed by pressing a single-sided perforation method to create a pit shape with an opening on one side. The tank area is divided into upper and lower tanks, folded in half, for placing the soft-pack battery cells, and the depth of the two tanks is the same as the thickness of the soft-pack battery cells; the air bag area uses aluminum-plastic film of the same specifications and material as the battery tank, and has a planar structure with the same dimensions as the planar projection dimensions of the battery tank, for holding the gas generated during the battery formation process.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] 1. This invention obtains an ant-nest-like carbon material by adjusting the heating rate and calcination temperature. It has a high specific surface area and abundant pore structure, which can effectively carry and restrict iodine active substances and improve the effective utilization rate of elemental iodine. Furthermore, the porous structure can restrict the dissolution and diffusion of intermediate polyiodide ions and suppress the shuttle effect, thereby effectively improving the specific capacity and cycle performance of the material.

[0028] 2. Zinc-iodine pouch batteries use aqueous electrolyte and graphite paper current collectors. Graphite paper has excellent high temperature resistance and thermal conductivity, with a maximum operating temperature of 400℃ and a maximum in-plane thermal conductivity of 1500W / mK. Its thermal resistance is 40% lower than that of aluminum and 20% lower than that of copper. This makes pouch batteries less prone to dangerous situations such as combustion or explosion. Even in the case of severe local heating, large-scale short circuits or temperature runaway explosions will not occur, avoiding the risk of fire when pouch batteries are damaged, and increasing the safety characteristics of zinc-iodine pouch batteries.

[0029] 3. Zinc-iodine pouch batteries use graphite paper as the current collector. Graphite paper is 30% lighter than aluminum of the same size and 80% lighter than copper. The use of graphite paper current collectors can significantly reduce the weight of the battery and improve the energy density of the pouch battery. In addition, the capacity of a single pouch battery cell can be increased by increasing the number of electrode layers, thereby further enhancing the energy density. Attached Figure Description

[0030] Figure 1 This is a scanning electron microscope image of the ant-nest-like carbon material prepared in Example 1 of the present invention;

[0031] Figure 2 The nitrogen adsorption-desorption curve of the ant nest-like carbon material prepared in Example 1 of this invention;

[0032] Figure 3 This is a scanning electron microscope image of the carbon material prepared in Comparative Example 1 of this invention;

[0033] Figure 4 The nitrogen adsorption-desorption curve of the carbon material prepared in Comparative Example 1 of this invention is shown below.

[0034] Figure 5 This is a scanning electron microscope image of the carbon material prepared in Comparative Example 2 of this invention;

[0035] Figure 6 The nitrogen adsorption-desorption curve of the carbon material prepared in Comparative Example 2 of this invention is shown below.

[0036] Figure 7 Cyclic voltammetry test curve of the zinc-iodine button cell prepared in Example 1 of this invention;

[0037] Figure 8 The constant current charge-discharge curve of the zinc-iodine button battery prepared in Example 1 of this invention;

[0038] Figure 9 The cycling curve of the zinc-iodine button cell prepared in Example 1 of this invention;

[0039] Figure 10 Cyclic voltammetry test curve of the zinc-iodine button cell prepared in Example 2 of this invention;

[0040] Figure 11 The cycling curve of the zinc-iodine button cell prepared in Example 2 of this invention;

[0041] Figure 12 Cyclic voltammetry test curve of the zinc-iodine button cell prepared in Example 3 of this invention;

[0042] Figure 13 The cycling curve of the zinc-iodine button cell prepared in Example 3 of this invention;

[0043] Figure 14 Cyclic voltammetry test curve of the zinc-iodine button cell prepared in Example 4 of this invention;

[0044] Figure 15 The cycling curve of the zinc-iodine button cell prepared in Example 4 of this invention;

[0045] Figure 16 Cyclic voltammetry test curve of the zinc-iodine button cell prepared in Example 5 of this invention;

[0046] Figure 17 An optical photograph of the pouch cell prepared in Example 4 of this invention;

[0047] Figure 18 The constant current charge-discharge curve of the soft-pack battery prepared in Example 4 of this invention;

[0048] Figure 19 This is a graph showing the energy density of the pouch cell prepared in Example 4 of the present invention as a function of the number of cycles.

[0049] Figure 20 This is a temperature comparison diagram between the soft-pack battery prepared in Example 4 of the present invention and a conventional soft-pack battery during the discharge process. Detailed Implementation

[0050] To facilitate understanding of the technical means, creative features, objectives, and effects of this invention, the following specific embodiments further illustrate the invention. The sources of all raw materials used in this invention are not particularly limited; they can be purchased commercially or prepared using conventional methods well-known to those skilled in the art. Their purity is not particularly limited, but analytical grade or conventional purity used in the field of composite materials is preferred. The following specific examples illustrate the implementation of this invention, allowing those skilled in the art to easily understand other advantages and effects of the invention from the content disclosed in this specification. This invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the invention. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other.

[0051] Example 1:

[0052] A method for preparing an ant-nest-like carbon material, the method comprising:

[0053] (1) Dissolve 1 mole of zinc nitrate hexahydrate and 4 moles of dimethylimidazole in 200 mL of methanol, stir at room temperature for 12 hours, filter and collect the prepared product, wash it 3 times with methanol, freeze dry overnight, and finally obtain ZIF-8 powder.

[0054] (2) The 0.5 g ZIF-8 prepared in step (1) was heated to 950 degrees Celsius at a heating rate of 3 degrees Celsius per minute under an argon atmosphere and calcined at 950 degrees Celsius for 4 hours to obtain ant nest-like carbon material.

[0055] Figure 1 The image shows a scanning electron microscope (SEM) image of the carbon material prepared in Example 1 of this invention. As can be seen from the image, the material exhibits a structure similar to an ant nest.

[0056] Figure 2 The nitrogen adsorption-desorption curve of the carbon material prepared in Example 1 of this invention is shown. The specific surface area of ​​the material is 1101.7 m² / g, and it is mainly composed of micropores. The abundant specific surface area and narrow mesopores are conducive to the adsorption of iodine in the carbon material.

[0057] Example 2:

[0058] A method for preparing an ant-nest-like carbon material, the method comprising:

[0059] (1) Dissolve 1 mole of zinc nitrate hexahydrate and 4 moles of dimethylimidazole in 200 mL of methanol, stir at room temperature for 12 hours, filter and collect the prepared product, wash it three times with methanol, freeze dry overnight, and finally obtain ZIF-8 powder.

[0060] (2) The 0.5 g ZIF-8 prepared in step (1) was heated to 900 degrees Celsius at a heating rate of 3 degrees Celsius per minute under an argon atmosphere and calcined at 900 degrees Celsius for 4 hours to obtain ant nest-like carbon material.

[0061] Example 3:

[0062] A method for preparing an ant-nest-like carbon material, the method comprising:

[0063] (1) Dissolve 1 mole of zinc nitrate hexahydrate and 4 moles of dimethylimidazole in 200 mL of methanol, stir at room temperature for 12 hours, filter and collect the prepared product, wash it three times with methanol, freeze dry overnight, and finally obtain ZIF-8 powder.

[0064] (2) The 0.5 g ZIF-8 prepared in step (1) was heated to 1000 degrees Celsius at a heating rate of 3 degrees Celsius per minute under an argon atmosphere and calcined at 1000 degrees Celsius for 4 hours to obtain ant nest-like carbon material.

[0065] Comparative Example 1

[0066] This comparative example provides a method for preparing a carbon material, which is the same as that in Example 1, except that in step (2), the temperature is raised to 800 degrees Celsius and calcined at 800 degrees Celsius for 4 hours.

[0067] Figure 3 The image shows a scanning electron microscope (SEM) image of the carbon material prepared in Comparative Example 1 of this invention. As can be seen from the image, the material basically maintains the original morphology and structure of ZIF8, with unvolatile elemental zinc present around it.

[0068] Figure 4 The nitrogen adsorption-desorption curve of the carbon material prepared in Comparative Example 1 of this invention is shown. The specific surface area of ​​the material is 87.55 m² / g, and it is mainly mesoporous. The small specific surface area is mainly due to the blockage of pores caused by the precipitation of elemental zinc in ZIF-8 at 800 degrees Celsius.

[0069] Comparative Example 2

[0070] This comparative example provides a method for preparing carbon materials, which is the same as that in Example 1, except that the heating rate is adjusted to 5 degrees Celsius per minute.

[0071] Figure 5 The image shows a scanning electron microscope (SEM) image of the carbon material prepared in Comparative Example 2 of this invention. As can be seen from the image, the material exhibits a layered structure.

[0072] Figure 6 The nitrogen adsorption-desorption curve of the carbon material prepared in Comparative Example 2 of this invention is shown. The specific surface area of ​​the material is 713.79 m² / g, and the mesopores and micropores are uniformly distributed.

[0073] Application Example 1

[0074] The ant-nest-like carbon material obtained in Example 1 was applied to a zinc-iodine button cell for electrochemical testing.

[0075] Take 0.1 g of the ant-nest-shaped carbon material prepared in Example 1, mix it evenly with 0.15 g of elemental iodine, and place it in a stainless steel reactor with a polytetrafluoroethylene liner. Heat it in a forced-air oven at 130 degrees Celsius for 5 hours. After heating, take the powder and dry it in an oven at 130 degrees Celsius for 1 hour to remove residual iodine on the surface, thus obtaining iodine-loaded carbon material. The iodine loading is determined to be 55% according to the formula for calculating the iodine loading of the material. Mix the prepared iodine-loaded carbon material powder, superconducting carbon black, and LA133 type water-based binder in a degassing machine at a mass ratio of 7:2:1 for 2 hours. Coat it evenly on a circular graphite paper with a diameter of 1 cm and dry it in a vacuum oven at 60 degrees Celsius for 12 hours.

[0076] A button cell was assembled using a dried electrode as the positive electrode, a zinc sheet as the negative electrode, and a 50 μL aqueous solution containing 2 moles of ZnSO4 and 0.05 moles of potassium iodide as the electrolyte. Cyclic voltammetry was performed at a scan rate of 5 mV / s within a potential window of 0.6–1.6 volts. Figure 7 As shown.

[0077] Figure 8 The constant current charge-discharge curve of the button battery prepared in Application Example 1 of this invention is shown. At a current density of 1 A / g, the constant current charge-discharge curves of the first 1-11 cycles are basically overlapping and remain unchanged, which is 204.8 mAh / g, indicating that the carbon material has good rate performance.

[0078] Figure 9 The cycling curve of the button cell prepared in Application Example 1 of this invention is shown at 1 amp / g. The ant-nest-like carbon material has a specific capacity of 206.8 mAh / g at 1 amp / g and retains 89.9% of its capacity after 10,000 cycles, showing a long service life potential.

[0079] Application Example 2

[0080] The ant-nest-like carbon material obtained in Example 2 was applied to a zinc-iodine button cell for electrochemical testing.

[0081] 0.1 g of the ant-nest-shaped carbon material prepared in Example 2 was mixed evenly with 0.15 g of elemental iodine and placed in a stainless steel reactor with a polytetrafluoroethylene liner. The mixture was then heated in a forced-air oven at 130 degrees Celsius for 5 hours. After heating, the powder was dried in an oven at 130 degrees Celsius for 1 hour to remove residual iodine from the surface, resulting in iodine-loaded carbon material. The iodine loading was determined to be 37.5% according to the formula for calculating the iodine loading of the material. The prepared iodine-loaded carbon material powder, superconducting carbon black, and LA133 water-based binder were mixed in a degassing machine at a mass ratio of 7:2:1 for 2 hours. The mixture was then evenly coated onto a circular graphite paper with a diameter of 1 cm and dried in a vacuum oven at 60 degrees Celsius for 12 hours.

[0082] A button cell was assembled using a dried electrode as the positive electrode, a zinc sheet as the negative electrode, and a 50 μL aqueous solution containing 2 moles of ZnSO4 and 0.05 moles of potassium iodide as the electrolyte. Cyclic voltammetry was performed at a scan rate of 5 mV / s within a potential window of 0.6–1.6 volts. Figure 10 As shown.

[0083] Figure 11 The cycling curve of the button cell prepared in Application Example 2 of the present invention is shown at 1 amp / g; the carbon material has a specific capacity of 193.7 mAh / g at 1 amp / g and retains 76.5% of its capacity after 10,000 cycles.

[0084] Application Example 3

[0085] The ant-nest-like carbon material obtained in Example 3 was applied to a zinc-iodine button cell for electrochemical testing.

[0086] 0.1 g of the ant-nest-shaped carbon material prepared in Example 3 was mixed evenly with 0.15 g of elemental iodine and placed in a stainless steel reactor with a polytetrafluoroethylene liner. The mixture was then heated in a forced-air oven at 130°C for 5 hours. After heating, the powder was dried in an oven at 130°C for 1 hour to remove residual iodine, resulting in iodine-loaded carbon material. The iodine loading was determined to be 45.8% according to the formula for calculating the iodine loading of the material in the invention. The prepared iodine-loaded carbon material powder, superconducting carbon black, and LA133 water-based binder were mixed in a degassing machine at a mass ratio of 7:2:1 for 2 hours. This mixture was then evenly coated onto a circular graphite paper with a diameter of 1 cm and dried in a vacuum oven at 60°C for 12 hours.

[0087] A button cell was assembled using a dried electrode as the positive electrode, a zinc sheet as the negative electrode, and a 50 μL aqueous solution containing 2 moles of ZnSO4 and 0.05 moles of potassium iodide as the electrolyte. Cyclic voltammetry was performed at a scan rate of 5 mV / s within a potential window of 0.6–1.6 volts. Figure 12 As shown.

[0088] Figure 13 The cycling curve of the button cell prepared in Application Example 3 of the present invention is shown at 1 amp / g; the carbon material has a specific capacity of 187.2 mAh / g at 1 amp / g and retains 82.5% of its capacity after 10,000 cycles.

[0089] Application Example 4

[0090] The carbon material obtained in Comparative Example 1 was applied to a zinc-iodine button cell for electrochemical testing.

[0091] Take 0.1 g of the ant-nest-shaped carbon material prepared in Comparative Example 1, mix it evenly with 0.15 g of elemental iodine, and place it in a stainless steel reactor with a polytetrafluoroethylene liner. Heat it in a forced-air oven at 130 degrees Celsius for 5 hours. After heating, take the powder and dry it in an oven at 130 degrees Celsius for 1 hour to remove residual iodine on the surface, thus obtaining iodine-loaded carbon material. According to the iodine loading calculation formula in the invention, the iodine loading is determined to be 17.7%. Mix the prepared iodine-loaded carbon material powder, superconducting carbon black, and LA133 type water-based binder in a degassing machine at a mass ratio of 7:2:1 for 2 hours. Coat it evenly on a circular graphite paper with a diameter of 1 cm and dry it in a vacuum oven at 60 degrees Celsius for 12 hours.

[0092] A button cell was assembled using a dried electrode as the positive electrode, a zinc sheet as the negative electrode, and a 50 μL aqueous solution containing 2 moles of ZnSO4 and 0.05 moles of potassium iodide as the electrolyte. Cyclic voltammetry was performed at a scan rate of 5 mV / s within a potential window of 0.6–1.6 volts. Figure 14As shown.

[0093] Figure 15 The cycling curve of the button cell prepared in Comparative Example 1 of this invention is shown at 1 A / g; the carbon material has a specific capacity of 181.3 mAh / g at 1 A / g and retains 67.8% of its capacity after 10,000 cycles.

[0094] Application Example 5

[0095] The carbon material obtained in Comparative Example 2 was applied to a zinc-iodine button cell for electrochemical testing.

[0096] Take 0.1 g of the ant-nest-shaped carbon material prepared in Comparative Example 2, mix it evenly with 0.15 g of elemental iodine, and place it in a stainless steel reactor with a polytetrafluoroethylene liner. Heat it in a forced-air oven at 130 degrees Celsius for 5 hours. After heating, take the powder and dry it in an oven at 130 degrees Celsius for 1 hour to remove residual iodine on the surface, thus obtaining iodine-loaded carbon material. According to the formula for calculating the iodine loading of the material in the invention, the iodine loading is determined to be 35%. Mix the prepared iodine-loaded carbon material powder, superconducting carbon black, and LA133 type water-based binder in a degassing machine at a mass ratio of 7:2:1 for 2 hours. Coat it evenly on a circular graphite paper with a diameter of 1 cm and dry it in a vacuum oven at 60 degrees Celsius for 12 hours.

[0097] A button cell was assembled using a dried electrode as the positive electrode, a zinc sheet as the negative electrode, and a 50 μL aqueous solution containing 2 moles of ZnSO4 and 0.05 moles of potassium iodide as the electrolyte. Cyclic voltammetry was performed at a scan rate of 5 mV / s within a potential window of 0.6–1.6 volts. Figure 16 As shown.

[0098] Example 4

[0099] A zinc-iodine soft-pack battery includes the following steps

[0100] Step (1): Take 0.1 g of the ant nest carbon material prepared in Example 1, mix it evenly with 0.15 g of iodine, and put it into a stainless steel reaction vessel with a polytetrafluoroethylene liner. Place it in a forced-air oven at 130 degrees Celsius for 5 hours to seal the iodine. After heating, take the powder and dry it in an oven at 130 degrees Celsius for 1 hour to remove the residual iodine on the surface, and obtain the iodine-loaded carbon material. According to the formula for calculating the iodine loading of the material in the invention, the iodine loading is determined to be 55%.

[0101] Step (2): Solvent the LA133 water-based adhesive and deionized water at a mass ratio of 3:97, and stir at high speed for 1 hour to make adhesive solution 1. The stirring speed is 800 rpm.

[0102] Step (3): Mix and grind the superconducting carbon black and the ant nest carbon material sealed with iodine evenly and add it to the prepared adhesive liquid 1 above. Stir at high speed for 2 hours to obtain mixture 1. The stirring speed is 1500 rpm. The iodine-loaded carbon material powder, superconducting carbon black and LA133 water-based binder are mixed in a ratio of 7:2:1.

[0103] Step (4): Adjust the viscosity range of mixture 1 to 1800 MPa.S and the fineness to 15 μm to obtain zinc-iodine battery positive electrode slurry;

[0104] Step (5): The zinc-iodine battery positive electrode slurry is evenly coated onto the cut graphite paper current collector, dried, and the coating is completed to obtain the zinc-iodine battery positive electrode sheet with a width of 60mm and a length of 70mm.

[0105] Step (6): The positive electrode sheet and negative zinc sheet of the zinc-iodine battery are wound with the glass fiber separator in a positive-negative opposite manner to form a soft-pack battery cell, and the core is covered with adhesive tape.

[0106] Step (7): Assemble with the pre-stamped and cut aluminum-plastic film to a specified depth, and seal the top and sides to form an unfilled soft-pack battery cell; the aluminum-plastic film is divided into two parts: a tank area and an air bag area; the thickness of the aluminum-plastic film is 150μm; the tank area is formed by single-sided punching, pressing on the dark side to form a pit shape with an opening on one side. The tank area is divided into upper and lower tanks, folded in half, for placing the soft-pack battery cell, and the depth of the two tanks is the same as the thickness of the soft-pack battery cell; the air bag area uses aluminum-plastic film of the same specifications and material as the battery tank, is a planar structure, and has the same size as the planar projection size of the battery tank, for holding the gas generated during the battery formation process;

[0107] Step (8): Inject 1.3 ml of electrolyte containing 2 moles of zinc sulfate and 0.05 moles of potassium iodide into the unfilled soft-pack battery cell, pre-seal the top side to form an filled soft-pack battery; pre-seal the side of the air bag area to form an filled soft-pack battery cell;

[0108] Step (9): Allow the electrolyte-filled soft-pack battery to stand until it is fully soaked in electrolyte, then vent and seal it to form a zinc-iodine soft-pack battery.

[0109] Figure 17 An optical photograph of the soft-pack battery (zinc-iodine soft-pack battery obtained in Example 4) prepared in Example 4 of the present invention;

[0110] Figure 18 The constant current charge-discharge curve of the soft-pack battery prepared in Example 4 of the present invention is shown; its charge-discharge potential range is 0.6-1.6 volts, and a specific capacity of 260 mAh / g was obtained after charge-discharge testing.

[0111] Figure 19 The energy density curve of the soft-pack battery prepared in Example 4 of this invention is shown; the energy density is 251.6 Wh / kg (calculated based on the mass of the active material iodine), which is a certain improvement compared to conventional soft-pack batteries.

[0112] Figure 20 This is a temperature comparison graph between the soft-pack battery prepared in Example 4 of the present invention and a conventional soft-pack battery during the discharge process. The conventional soft-pack battery gradually increases in size with increasing discharge time, exhibiting a linear increasing trend, reaching a maximum temperature of 49 degrees Celsius. In contrast, the zinc-iodine soft-pack battery only reaches a maximum of 37.5 degrees Celsius, a reduction of 11.5 degrees Celsius compared to the conventional soft-pack battery. This is due to the combined effect of the high heat resistance and thermal conductivity of the graphite paper current collector and the application of an aqueous electrolyte, which effectively reduces the temperature of the zinc-iodine soft-pack battery, preventing the risk of fire and explosion and improving its safety performance.

[0113] This invention belongs to the field of aqueous battery technology and discloses a method for preparing ant nest-like carbon material and a zinc-iodine soft-pack battery. The preparation method includes: (1) preparing ZIF-8 material with zinc nitrate hexahydrate and 2-methylimidazole; (2) calcining the material obtained in step (1) to obtain ant nest-like carbon material; the zinc-iodine soft-pack battery includes a zinc foil negative electrode, an ant nest-like carbon material positive electrode, a glass fiber separator and an electrolyte; the ant nest-like carbon material prepared by the method of this invention through adjusting the calcination temperature and heating rate has a high specific surface area and rich pore structure, which can effectively carry and restrict iodine active substances and improve the effective utilization rate of iodine; it can restrict the dissolution and diffusion of intermediate product polyiodide ions, effectively enhancing its cycle performance to only 10.1% decay after 10,000 cycles; and it is inexpensive, simple to prepare, and highly repeatable; when matched with zinc foil to form a zinc-iodine soft-pack battery, using an aqueous electrolyte and a graphite paper current collector, it is not easy to cause dangerous situations such as combustion or explosion. Due to the excellent thermal conductivity and heat resistance of graphite paper, zinc-iodine pouch batteries will not experience large-scale short circuits or temperature runaway explosions even in cases of severe localized heating, thus ensuring safety. Compared to other pouch batteries, the application of graphite paper current collectors demonstrates a trend towards increased energy density.

[0114] This invention discloses a method for preparing an ant-nest-like carbon material and a zinc-iodine soft-pack battery. The ant-nest-like carbon material prepared by this method has a high specific surface area and abundant pore structure, which can effectively carry and confine iodine active substances, improving the effective utilization rate of elemental iodine. The combination of polyiodide and abundant pore surface functional groups can inhibit the dissolution and diffusion of iodine and suppress the shuttle effect. Using graphite paper as the current collector instead of the traditional copper / aluminum foil current collector effectively solves the current difficulties in improving energy density and safety in soft-pack batteries. Due to the low density, high temperature resistance, and good thermal conductivity of the graphite paper current collector, it can significantly improve energy density and effectively conduct heat generated inside the battery. The use of an aqueous electrolyte can prevent battery explosion and fire caused by temperature runaway. This provides strong technical support for the future commercial production of graphite paper fluid soft-pack batteries. The results show that the application of graphite paper current collector and aqueous electrolyte ensures that the battery has high energy density and safety performance, providing technical support for the future commercial production of graphite paper current collector soft-pack batteries.

[0115] The embodiments described above are merely illustrative of specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for producing an ant-hill-like carbon material, characterized by, The preparation method includes: (1) Zinc salt and organic ligand are mixed in a solvent and reacted at room temperature by stirring or standing to synthesize ZIF-8; (2) The ZIF-8 prepared in step (1) was calcined at high temperature and under an argon atmosphere to obtain ant nest carbon material; The zinc salt in step (1) is zinc nitrate hexahydrate; the organic ligand is 2-methylimidazole; the solvent includes methanol; the zinc salt in step (1) is 1-4 moles; the organic ligand is 4-8 moles; the volume of the solvent is 200-500 ml; The molar ratio of zinc salt and organic ligand in step (1) is 1:4; The high temperature mentioned in step (2) is 900-1000 degrees Celsius; The heating rate of the high temperature in step (2) is 2-3 degrees Celsius / minute; the calcination time is 1-4 hours.

2. A zinc-iodine soft pack battery, characterized by, Its preparation method includes the following steps: Step (1): Take a mass ratio of (1:1) - (1: The ant nest carbon material described in claim 1 of (1.5) is mixed with iodine in a high-pressure reactor and reacted in a forced-air drying oven at 100-140 degrees Celsius for 2-6 hours for iodine sealing, thereby obtaining the ant nest carbon material with iodine sealing completed. Step (2): Solve the LA133 water-based adhesive and deionized water, and stir at high speed for 1-2 hours to make adhesive solution 1; Step (3): Mix and grind the superconducting carbon black and the ant nest-like carbon material sealed with iodine evenly, add it to the above-prepared adhesive solution 1, and stir at high speed for 1-2 hours to obtain mixture 1; Step (4): Adjust the viscosity of mixture 1 to obtain zinc-iodine battery positive electrode slurry; Step (5): The zinc-iodine battery positive electrode slurry from step (4) is uniformly coated onto the cut graphite paper current collector, dried, and the coating is completed to obtain the zinc-iodine battery positive electrode sheet. Step (6): The positive electrode sheet and negative zinc sheet of the zinc-iodine battery are wound with the glass fiber separator in a positive-negative opposite manner to form a soft-pack battery cell, and the core is covered with finishing glue. Step (7): Assemble with the pre-stamped and cut aluminum-plastic film to a specified depth, and seal the top and sides to form an unfilled soft-pack battery cell; Step (8): Inject an electrolyte containing zinc sulfate and potassium iodide into the unfilled soft-pack cell, and pre-seal the top side to form an electrolyte-filled soft-pack battery; Step (9): Allow the electrolyte-filled soft-pack battery to stand until it is fully soaked in the electrolyte to form a zinc-iodine soft-pack battery.

3. The zinc-iodine soft pack battery according to claim 2, characterized in that, In step (2), LA133 water-based adhesive and deionized water are sol-gelled at a mass ratio of 3:

97.

4. The zinc-iodine soft pack battery according to claim 2, characterized by, The mass ratio of the LA133 water-based adhesive in step (2) and the superconducting carbon black in step (3) to the ant nest carbon material sealed with iodine is 7:2:1.

Images