Iodine-carbon composite material and preparation method thereof

Abstract

The invention provides an iodine-carbon composite material and a preparation method thereof, and relates to the technical field of composite material preparation, the preparation method of the iodine-carbon composite material comprises the following steps: taking conidium powder to prepare fixed conidium powder, adding the fixed conidium powder into sulfuric acid for reaction, then washing, neutralizing, and freeze-drying to obtain pretreated conidium powder; the pretreated conidium powder is firstly heated and then carbonized to prepare carbonized porous conidium powder, an iodine solution is prepared, the carbonized porous conidium powder is added into the iodine solution and stirred to be uniform, then deionized water is added, and the iodine-carbon composite material is obtained through filtering and drying. The iodine-carbon composite material can inhibit generation of dead lithium and activate existing dead lithium.

Description

Iodine-carbon composite materials and their preparation methods Technical Field

[0001] This invention relates to the field of composite materials technology, specifically to iodine-carbon composite materials and their preparation methods. Background Technology

[0002] In terms of energy density, traditional lithium-ion batteries have approached their theoretical limit. However, in various applications such as electric vehicles and grid energy storage, it is still necessary to further improve battery energy to meet society's growing demand for advanced power energy density.

[0003] Lithium ions (Li) are the charge carriers in traditional lithium-ion batteries and emerging lithium metal batteries, and are an indispensable medium for ensuring battery operation. Therefore, inactive lithium (often called dead lithium) existing in the form of solid electrolyte interphase (SEI) and metallic lithium is the main cause of battery capacity decay and insufficient lifespan. How to suppress the generation of dead lithium during battery use has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an iodine-carbon composite material and its preparation method, solving the technical problem of dead lithium generation during battery use.

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

[0006] In a first aspect, this invention provides a method for preparing an iodine-carbon composite material. The method involves preparing fixed conidium powder from conidial powder, reacting the fixed conidium powder in sulfuric acid, then washing, neutralizing, and freeze-drying to obtain pretreated conidium powder. The pretreated conidium powder is then heated and carbonized to prepare carbonized porous conidium powder. An iodine solution is prepared, and the carbonized porous conidium powder is added to the iodine solution and stirred until homogeneous. Deionized water is then added, and the mixture is filtered and dried to obtain the iodine-carbon composite material. The prepared iodine-carbon composite material uses biochar capsules as an iodine carrier and spontaneously generates I3 through a lithium reduction method based on the iodine redox reaction. − / I − Redox reactions can effectively reactivate dead lithium to compensate for lithium loss.

[0007] Preferably, the average diameter of the conidial powder is 4–6 µm.

[0008] Preferably, the conidial powder is added to ethanol, treated under ultrasound for 1-2 hours, then washed with deionized water, then added to a mixed solution of ethanol and formaldehyde for further treatment, and then centrifuged with deionized water to obtain fixed conidial powder.

[0009] Preferably, in the mixed solution of ethanol and formaldehyde, the ratio of ethanol to formaldehyde is v / v = 1~9:1~9.

[0010] Preferably, the sulfuric acid is 6-12M.

[0011] Preferably, the carbonization conditions for the pretreated conidial powder are: carbonization at 600-700℃ for 2-3 hours under an inert gas atmosphere, with a heating rate of 5-8℃·min⁻¹.

[0012] Preferably, the mass ratio of the carbonized porous conidial powder to the iodine in the iodine solution is 1:2-3.

[0013] Preferably, the drying temperature is 105–150°C.

[0014] Preferably, the preparation method of the iodine-carbon composite material includes the following steps:

[0015] S1. Take conidial powder as raw material, treat it with 50-100ml ethanol under ultrasound for 1-2 hours, and then wash it with deionized water.

[0016] S2. Treat the conidial powder with a mixed solution of 30-100 ml ethanol and formaldehyde, and centrifuge with deionized water to obtain fixed conidial powder.

[0017] S3. The fixed conidial powder is added to sulfuric acid and pre-carbonized at 70℃~80℃ for 2h~4h. After washing, it is neutralized and freeze-dried to obtain pretreated conidial powder.

[0018] S4. The pretreated conidial powder is heated at 200℃~300℃ for 2h~4h, and then carbonized at 600℃~700℃ for 2h~3h to obtain carbonized porous conidial powder.

[0019] S5. Dissolve a certain amount of iodine in 10ml-30ml of ethanol to obtain an orange-red solution. Then add the carbonized porous conidial powder and stir continuously for 1h-3h. Finally, add deionized water, filter and dry to obtain the iodine-carbon composite material.

[0020] In a second aspect, the present invention provides an iodine-carbon composite material prepared by the preparation method described in the first aspect, the iodine-carbon composite material comprising carbonized porous conidial powder and iodine, wherein the iodine is deposited on the carbonized porous conidial powder.

[0021] Compared with existing technologies, it has the following beneficial effects:

[0022] The iodine-carbon composite material prepared by the method described in this application uses biochar capsules as an iodine carrier and spontaneously generates I3 through lithium reduction via an iodine redox reaction. − / I− Redox reactions can effectively reactivate dead lithium to compensate for lithium loss. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] This application provides an iodine-carbon composite material and its preparation method, which solves the technical problem of generating inactive lithium during battery use.

[0025] The technical solution in this application is to solve the above-mentioned technical problems, and the general idea is as follows:

[0026] This invention provides an iodine-carbonized porous conidial powder composite material (i.e., iodine-carbon composite material), which utilizes a lithium reduction method via an iodine oxidation-reduction reaction, primarily involving I3. − / I − Using biochar capsules as iodine carriers, we found that I3 − / I − Redox reactions occur spontaneously and effectively reactivate dead lithium to compensate for lithium loss.

[0027] The specific process is as follows:

[0028] ① Reaction with Li2O in dead SEI film (core pathway 1)

[0029] The main component of the dead SEI film is Li2O, and the I3 released by the iodine-carbonized porous conidial powder composite material is... - It will undergo a redox reaction with Li₂O to produce soluble LiI and IO. 3- :3I3 - +3Li₂O=6Li + +8I - +IO3 - Subsequently, the LiIO3 generated in the reaction is reduced by lithium metal on the anode surface, transforming into Li2O and LiI:IO3. - +6Li=3Li₂O+I - This step achieves both the decomposition of Li2O in the dead SEI film and the release of lithium (in the form of LiI), and allows the reduced Li2O to be redeposited on the anode surface, forming a structurally stable healthy SEI film and avoiding the formation of new dead lithium.

[0030] ② Reaction with electrically isolated lithium metal fragments (core pathway two)

[0031] I3 in iodine-carbonized porous conidial powder composite material - It can also directly react with electrically isolated lithium metal fragments in a redox reaction, converting inactive lithium fragments into soluble LiI:I3. - +2Li (fragments) = 2Li + +3I - This reaction breaks the electrical isolation of lithium fragments, converting Li, which was originally unable to participate in the cycle, into a migratable lithium species (LiI), thus "reviving" the lithium fragments.

[0032] ③LiI shuttle and I3 - Regeneration (cycle-driven)

[0033] All the soluble LiI generated in the above two reactions will shuttle from the anode region to the cathode via ion conduction in the electrolyte. At the cathode surface, LiI reacts with delithiated LiFePO4 (LFP) to regenerate I3. - Species: 2Li + +3I + +2FePO4=I3 - I3 regenerated by +2LiFePO4 - It will migrate back to the anode and react again with the remaining dead SEI film or lithium fragments to form "I3". - →LiI→I3 - The reversible cycle continuously provides active species for the revival of dead lithium.

[0034] ④ Continuous construction of healthy SEI membranes and lithium cycling replenishment

[0035] During the reaction, Li2O generated from the reduction of LiIO3 is directionally deposited on the anode surface, gradually forming a healthy SEI film with uniform composition and stable structure, inhibiting the random deposition of lithium metal and the generation of new dead lithium; at the same time, all lithium species released by the reaction (ultimately in the form of Li) are also deposited. + The lithium is reintegrated into the battery charging and discharging process through cathode reactions (in the form of lithium participating in the cycle), effectively compensating for lithium loss.

[0036] With this design, a full cell using a very limited number of lithium metal anodes achieves an excellent cycle life of 1000 cycles and a high coulombic efficiency of 99.9%.

[0037] The preparation method provided by this invention is simple, uses inexpensive and readily available raw materials, and is easy to operate. It can effectively restore electrochemically active lithium in dead SEI and electrically isolated lithium metal fragments. The transfer of Li₂O from the dead SEI to the newly exposed lithium surface not only effectively eliminates the accumulation of dead SEI and lithium fragments during lithium plating / stripping cycles but also significantly inhibits electrolyte decomposition induced by highly active metals, a common feature in lithium batteries. Simultaneously, a cathode with a discharge voltage exceeding iodine redox (2.89V) can achieve reversible iodine shuttle, enabling the recovery of inactive lithium to the cathode.

[0038] To better understand the above technical solution, the following will provide a detailed explanation of the above technical solution in conjunction with specific implementation methods.

[0039] I. Preparation Method

[0040] Example 1

[0041] Preparation of iodine-carbonized porous conidial powder composite material: Conidial powder (average diameter 4µm) was used as raw material and treated with 50ml ethanol under ultrasonication for 1 hour, then washed several times with deionized water; the conidial powder was treated with a mixed solution of 50ml ethanol and formaldehyde (v / v=1:1), and centrifuged with deionized water to obtain fixed conidial powder; the fixed conidial powder was added to 12M sulfuric acid and reacted at 80℃ for 4 hours, washed, neutralized to pH=7, and freeze-dried to obtain pretreated conidial powder; the pretreated conidial powder was heated at 300℃ for 4 hours, and then carbonized at 700℃ for 2 hours to obtain carbonized porous conidial powder.

[0042] A certain amount of iodine was dissolved in 20 ml of ethanol to obtain an orange-red solution. Then, carbonized porous conidial powder was added, and the mixture was stirred continuously with iodine (the ratio of carbonized porous conidial powder to iodine was 1:2) for 2 hours. Finally, deionized water was added to allow iodine particles to precipitate and deposit on the carbonized porous conidial powder. After filtration and drying, an iodine-carbonized porous conidial powder composite material was obtained.

[0043] Preparation of iodine-carbon anode sheet: Iodine-carbonized porous conidial powder composite material, conductive agent SuperP, and binder PVDF were weighed at a mass ratio of 8:1:1, and N-methylpyrrolidone (NMP) was added. The mixture was stirred at 1000 rpm for 4 hours to form a uniform slurry (solid content 40%). The slurry was coated onto a 12µm copper foil current collector at a speed of 50 mm / min, with the wet film thickness controlled at 120µm. Subsequently, it was dried in a vacuum drying oven at 60℃ for 12 hours (vacuum degree -0.09MPa). The dried electrode sheet was then rolled to a compaction density of 1.2 g / cm³. 3 Cut into circular electrode sheets with a diameter of 12mm (area density of approximately 1.5mg / cm³). 2 This is the iodine-carbon anode plate, ready for use.

[0044] Example 2

[0045] Preparation of iodine-carbonized porous conidial powder composite material: Conidial powder (average diameter 6µm) was used as raw material and treated with 50ml ethanol under ultrasonication for 1 hour, then washed several times with deionized water; the conidial powder was treated with a mixed solution of 100ml ethanol and formaldehyde (v / v=2:1), and centrifuged with deionized water to obtain fixed conidial powder; the fixed conidial powder was added to 12M sulfuric acid and reacted at 80℃ for 4h, washed, neutralized to pH=7, and freeze-dried to obtain pretreated conidial powder; the pretreated conidial powder was heated at 300℃ for 4h, and then carbonized at 700℃ for 2h to obtain carbonized porous conidial powder.

[0046] A certain amount of iodine was dissolved in 20 ml of ethanol to obtain an orange-red solution. Then, carbonized porous conidial powder was added, and the mixture was stirred continuously with iodine (the ratio of carbonized porous conidial powder to iodine was 1:2) for 2 hours. Finally, deionized water was added to allow iodine particles to precipitate and deposit on the carbonized porous conidial powder. After filtration and drying, an iodine-carbonized porous conidial powder composite material was obtained.

[0047] Preparation of iodine-carbon anode sheet: Iodine-carbonized porous conidial powder composite material, conductive agent SuperP, and binder PVDF were weighed at a mass ratio of 8:1:1, and N-methylpyrrolidone (NMP) was added. The mixture was stirred at 1000 rpm for 4 hours to form a uniform slurry (solid content 40%). The slurry was coated onto a 12µm copper foil current collector at a speed of 50 mm / min, with the wet film thickness controlled at 120µm. Subsequently, it was dried in a vacuum drying oven at 60℃ for 12 hours (vacuum degree -0.09MPa). The dried electrode sheet was then rolled to a compaction density of 1.2 g / cm³. 3 Cut into circular electrode sheets with a diameter of 12mm (area density of approximately 1.5mg / cm³). 2 This is the iodine-carbon anode plate, ready for use.

[0048] Example 3

[0049] Preparation of iodine-carbonized porous conidial powder composite material: Conidial powder (average diameter 5µm) was used as raw material and treated with 50ml ethanol under ultrasonication for 1 hour, then washed several times with deionized water; the conidial powder was treated with a mixed solution of 50ml ethanol and formaldehyde (v / v=2:1), and centrifuged with deionized water to obtain fixed conidial powder; the fixed conidial powder was added to 12M sulfuric acid and reacted at 80℃ for 4 hours, washed, neutralized to pH=7, and freeze-dried to obtain pretreated conidial powder; the pretreated conidial powder was heated at 300℃ for 4 hours, and then carbonized at 700℃ for 2 hours to obtain carbonized porous conidial powder.

[0050] A certain amount of iodine was dissolved in 20 ml of ethanol to obtain an orange-red solution. Then, carbonized porous conidial powder was added, and the mixture was stirred continuously with iodine (the ratio of carbonized porous conidial powder to iodine was 1:1) for 2 hours. Finally, deionized water was added to allow iodine particles to precipitate and deposit on the carbonized porous conidial powder. After filtration and drying, an iodine-carbonized porous conidial powder composite material was obtained.

[0051] Preparation of iodine-carbon anode sheet: Iodine-carbonized porous conidial powder composite material, conductive agent SuperP, and binder PVDF were weighed at a mass ratio of 8:1:1, and N-methylpyrrolidone (NMP) was added. The mixture was stirred at 1000 rpm for 4 hours to form a uniform slurry (solid content 40%). The slurry was coated onto a 12µm copper foil current collector at a speed of 50 mm / min, with the wet film thickness controlled at 120µm. Subsequently, it was dried in a vacuum drying oven at 60℃ for 12 hours (vacuum degree -0.09MPa). The dried electrode sheet was then rolled to a compaction density of 1.2 g / cm³. 3 Cut into circular electrode sheets with a diameter of 12mm (area density of approximately 1.5mg / cm³). 2 This is the iodine-carbon anode plate, ready for use.

[0052] Example 4

[0053] Preparation of iodine-carbonized porous conidial powder composite material: Conidial powder (average diameter 4µm) was used as raw material and treated with 50ml ethanol under ultrasonication for 1 hour, then washed several times with deionized water; the conidial powder was treated with a mixed solution of 50ml ethanol and formaldehyde (v / v=2:1), and centrifuged with deionized water to obtain fixed conidial powder; the fixed conidial powder was added to 12M sulfuric acid and reacted at 80℃ for 4 hours, washed, neutralized to pH=7, and freeze-dried to obtain pretreated conidial powder; the pretreated conidial powder was heated at 300℃ for 4 hours, and then carbonized at 700℃ for 2 hours to obtain carbonized porous conidial powder.

[0054] A certain amount of iodine was dissolved in 20 ml of ethanol to obtain an orange-red solution. Then, carbonized porous conidial powder was added, and the mixture was stirred continuously with iodine (the ratio of carbonized porous conidial powder to iodine was 1:3) for 2 hours. Finally, deionized water was added to allow iodine particles to precipitate and deposit on the carbonized porous conidial powder. After filtration and drying, an iodine-carbonized porous conidial powder composite material was obtained.

[0055] Preparation of iodine-carbon anode sheet: Iodine-carbonized porous conidial powder composite material, conductive agent SuperP, and binder PVDF were weighed at a mass ratio of 8:1:1, and N-methylpyrrolidone (NMP) was added. The mixture was stirred at 1000 rpm for 4 hours to form a uniform slurry (solid content 40%). The slurry was coated onto a 12µm copper foil current collector at a speed of 50 mm / min, with the wet film thickness controlled at 120µm. Subsequently, it was dried in a vacuum drying oven at 60℃ for 12 hours (vacuum degree -0.09MPa). The dried electrode sheet was then rolled to a compaction density of 1.2 g / cm³. 3 Cut into circular electrode sheets with a diameter of 12mm (area density of approximately 1.5mg / cm³). 2 This is the iodine-carbon anode plate, ready for use.

[0056] Example 5

[0057] Preparation of iodine-carbonized porous conidial powder composite material: Conidial powder (average diameter 4µm) was used as raw material and treated with 50ml ethanol under ultrasonication for 1 hour, then washed several times with deionized water; the conidial powder was treated with a mixed solution of 50ml ethanol and formaldehyde (v / v=1:1), and centrifuged with deionized water to obtain fixed conidial powder; the fixed conidial powder was added to 12M sulfuric acid and reacted at 80℃ for 4 hours, washed, neutralized to pH=7, and freeze-dried to obtain pretreated conidial powder; the pretreated conidial powder was heated at 300℃ for 4 hours, and then carbonized at 700℃ for 2 hours to obtain carbonized porous conidial powder.

[0058] A certain amount of iodine was dissolved in 20 ml of ethanol to obtain an orange-red solution. Then, carbonized porous conidial powder was added, and the mixture was stirred continuously with iodine (the ratio of carbonized porous conidial powder to iodine was 1:4) for 2 hours. Finally, deionized water was added to allow iodine particles to precipitate and deposit on the carbonized porous conidial powder. After filtration and drying, an iodine-carbonized porous conidial powder composite material was obtained.

[0059] Preparation of iodine-carbon anode sheet: Iodine-carbonized porous conidial powder composite material, conductive agent SuperP, and binder PVDF were weighed at a mass ratio of 8:1:1, and N-methylpyrrolidone (NMP) was added. The mixture was stirred at 1000 rpm for 4 hours to form a uniform slurry (solid content 40%). The slurry was coated onto a 12µm copper foil current collector at a speed of 50 mm / min, with the wet film thickness controlled at 120µm. Subsequently, it was dried in a vacuum drying oven at 60℃ for 12 hours (vacuum degree -0.09MPa). The dried electrode sheet was then rolled to a compaction density of 1.2 g / cm³. 3 Cut into circular electrode sheets with a diameter of 12mm (area density of approximately 1.5mg / cm³). 2 This is the iodine-carbon anode plate, ready for use.

[0060] Battery assembly:

[0061] 1. Button cell (for lithium deposition / stripping testing)

[0062] Assembly environment: Argon glove box (water and oxygen content <0.1ppm);

[0063] Assembly process: Stack the CR2032 battery case, the iodine-carbon anode sheet prepared in Examples 1-2, the separator (Celgard 2400, diameter 16 mm), and the lithium metal counter electrode (diameter 14 mm) in sequence. Add 20 µL of electrolyte (1 M LiPF6 / EC:DMC=1:1, containing 2% FEC), seal the package, and let it stand for 12 h to activate.

[0064] 2. Button cell full cell (long cycle performance test)

[0065] Cathode preparation: LiFePO4, SuperP, and PVDF were mixed in a ratio of 8:1:1, NMP was added to form a slurry, and the mixture was coated onto aluminum foil. After drying and rolling, the slurry was cut into cathode sheets with a diameter of 12 mm (area density of approximately 2 mg / cm³). 2 );

[0066] Assembly process: In the glove box, stack the iodine carbon anode sheet prepared in Examples 3-5 → diaphragm → LiFePO4 cathode sheet, add 30µL of electrolyte, seal and let stand for 24h to activate.

[0067] Comparative Example 1

[0068] The difference between this comparative example and Example 1 is that the carbonized porous conidial powder prepared in Example 1 is used instead of the iodine-carbonized porous conidial powder composite material in Example 1 to prepare the anode electrode, which is referred to as the carbonized porous conidial powder anode electrode. The assembly of the button half-cell includes the following steps:

[0069] Assembly environment: Argon glove box (water and oxygen content <0.1ppm);

[0070] Assembly process: Stack the CR2032 battery case, the carbonized porous conidial powder anode sheet prepared in this comparative example, the separator (Celgard2400, diameter 16mm), and the lithium metal counter electrode (diameter 14mm) in sequence. Add 20µL of electrolyte (1MLiPF6 / EC:DMC=1:1, containing 2%FEC), seal, and let stand for 12h for activation.

[0071] Comparative Example 2

[0072] This comparative example provides a button cell, and the specific steps are as follows:

[0073] Cathode preparation: LiFePO4, SuperP, and PVDF were mixed in a ratio of 8:1:1, NMP was added to form a slurry, and the mixture was coated onto aluminum foil. After drying and rolling, the slurry was cut into cathode sheets with a diameter of 12 mm (area density of approximately 2 mg / cm³). 2 );

[0074] Assembly process: Stack the Li@Cu anode sheet → diaphragm → LiFePO4 cathode sheet in the glove box, add 30µL of electrolyte, seal and let stand for 24 hours to activate.

[0075] II. Testing Methods

[0076] The assembled batteries were subjected to performance tests, and the test items and methods are as follows:

[0077] 1. Lithium deposition / stripping coulombic efficiency (CE) test:

[0078] Coin cell half-cell at "deposition 1mAh / cm 2 —In the "strip to 1V" cycling mode, different current densities (1 / 3 / 5mA / cm) were tested. 2 CE changes under ( )

[0079] 2. Long-cycle capacity retention test:

[0080] The relationship between the number of cycles and capacity of button cell batteries under 0.5C charge-discharge (charged to 3.6V and discharged to 2.4V) was recorded.

[0081] 3. Quantitative analysis of dead lithium:

[0082] After 100 cycles, the batteries of Examples 1-5 and Comparative Examples 1-2 were disassembled, and the content of residual lithium on the anode surface was tested by ICP-OES (dead lithium is lithium that cannot be peeled off), while the morphology of lithium on the anode surface was observed.

[0083] III. Test Results

[0084] The performance test results of the assembled batteries are shown in Table 1.

[0085] Table 1 Battery performance test results

[0086]

[0087] As shown in Table 1, compared with Comparative Examples 1 and 2, the coin cells prepared in Examples 1-2 have a CE of approximately 99.9% after 1000 cycles, which is higher. This indicates that the batteries prepared in Examples 1-2 have less dead lithium (electrolyzed lithium / SEI-encapsulated lithium) formation, and the dead lithium is converted into active lithium. Compared with Comparative Examples 1 and 2, the full cells prepared in Examples 3-5 retain approximately 85% of their capacity after 1000 cycles, and the capacity decay is slower. This indicates that the lithium loss caused by dead lithium is compensated by the iodine-carbonized porous conidial powder composite material, meaning that the dead lithium in the full cells prepared in Examples 3-5 of this application can also be restored to active lithium.

[0088] The dead lithium content of the batteries prepared in Examples 1-5 after cycling was approximately 0.2 mg / cm³. 2 The dead lithium content in the anode of the iodine-carbonized porous conidial powder composite material was only 1 / 5 that of the carbonized porous conidial powder anode, directly proving that dead lithium was effectively recovered. The battery anodes prepared in Examples 1-5 showed no dead lithium fragments, indicating that the iodine-carbonized porous conidial powder composite material inhibited the formation of dead lithium and activated existing dead lithium.

[0089] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0090] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0091] The present invention has been illustrated with the above embodiments to describe the detailed process flow of the present invention. However, the present invention is not limited to the above detailed process flow, that is, it does not mean that the present invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing an iodine-carbon composite material, characterized in that, Fixed conidial powder was prepared by taking conidial powder and reacting it in sulfuric acid. Then, it was washed, neutralized, and freeze-dried to obtain pretreated conidial powder. The pretreated conidial powder was first heated and then carbonized to prepare carbonized porous conidial powder. An iodine solution was prepared, and the carbonized porous conidial powder was added to the iodine solution and stirred evenly. Then, deionized water was added, and the mixture was filtered and dried to obtain an iodine-carbon composite material.

2. The method for preparing the iodine-carbon composite material as described in claim 1, characterized in that, The average diameter of the conidial powder is 4–6 µm.

3. The method for preparing the iodine-carbon composite material as described in claim 1, characterized in that, The conidial powder was added to ethanol and treated under ultrasound for 1-2 hours. Then it was washed with deionized water and treated in a mixed solution of ethanol and formaldehyde. Finally, it was centrifuged with deionized water to obtain fixed conidial powder.

4. The method for preparing the iodine-carbon composite material as described in claim 3, characterized in that, In the mixed solution of ethanol and formaldehyde, the ratio of ethanol to formaldehyde is v / v = 1~9:1~9.

5. The method for preparing the iodine-carbon composite material as described in claim 1, characterized in that, The sulfuric acid is 6-12M.

6. The method for preparing the iodine-carbon composite material as described in claim 1, characterized in that, The carbonization conditions for the pretreated conidial powder are as follows: carbonization at 600–700°C for 2–3 hours under an inert gas atmosphere, with a heating rate of 5–8°C·min. -1 .

7. The method for preparing the iodine-carbon composite material as described in claim 1, characterized in that, The mass ratio of the carbonized porous conidial powder to the iodine in the iodine solution is 1:2-3.

8. The method for preparing the iodine-carbon composite material as described in claim 1, characterized in that, The drying temperature is 105–150°C.

9. The method for preparing the iodine-carbon composite material as described in claim 1, characterized in that, The process includes the following steps: S1. Using conidial powder as raw material, treat it with 50-100 ml of ethanol under ultrasonication for 1-2 hours, and then wash it with deionized water; S2. Treat the conidial powder with a mixed solution of 30-100 ml of ethanol and formaldehyde, and centrifuge it with deionized water to obtain fixed conidial powder; S3. Add the fixed conidial powder to sulfuric acid, pre-carbonize it at 70℃-80℃ for 2-4 hours, wash it, neutralize it, and freeze-dry it to obtain pretreated conidial powder; S4. Heat the pretreated conidial powder at 200℃-300℃ for 2-4 hours, and then carbonize it at 600℃-700℃ for 2-3 hours to obtain carbonized porous conidial powder; S5. Dissolve a certain amount of iodine in 10 ml-30 ml of ethanol, then add the carbonized porous conidial powder, stir continuously for 1-3 hours, finally add deionized water, filter and dry to obtain iodine-carbon composite material.

10. An iodine-carbon composite material prepared by the preparation method according to any one of claims 1-9, characterized in that, The iodine-carbon composite material comprises carbonized porous conidial powder and iodine, wherein the iodine is deposited on the carbonized porous conidial powder.

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