Synthesis of large Co3O4 particles assisted by porous carbon framework and method thereof

Abstract

The application provides a method for synthesizing large-particle Co3O4 based on a porous carbon framework, which comprises the following steps: mixing a porous carbon framework, a cobalt salt, an alkali, a complexing agent, an oxidizing agent and a solvent, and obtaining cobalt oxyhydroxide / carbon composite particles through a co-precipitation reaction; wherein the addition amount of the porous carbon framework is 5-30% of the theoretical mass of Co3O4; and the cobalt oxyhydroxide / carbon composite particles are calcined to obtain Co3O4 with D50 greater than or equal to 10 mu m. The method introduces a porous carbon framework, provides an attachment point and a space confinement for the growth of cobalt oxyhydroxide in the synthesis stage, and the carbon framework is slowly oxidized and removed in the calcination stage, leaving uniformly distributed pores in situ, thereby forming a porous but not hollow dense structure, realizing the unification of large particle size and high tap density, and the obtained cobalt tetraoxide particles have a nanoscale uniform porous microstructure inside, ensuring the overall structural strength of the particles and high tap density.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery cathode material precursors, specifically to a method for synthesizing large-particle Co3O4 based on a porous carbon framework. Background Technology

[0002] Cobalt tetroxide (CTO) is an important precursor to lithium cobalt oxide, a cathode material for lithium-ion batteries. Its physical properties (such as particle size, tap density, and microstructure) directly determine the tap density of lithium cobalt oxide and the volumetric energy density of the battery. With the trend towards miniaturization and longer battery life in consumer electronics, the market demands CTOs with large particle size (D50 ≥ 10 μm) and high tap density (≥ 2.5 g / cm³). 3 The demand for cobalt tetroxide is becoming increasingly urgent.

[0003] Currently, the mainstream method for industrial production of large-particle cobalt tetroxide is to prepare large-particle cobalt carbonate or cobalt hydroxide through liquid-phase co-precipitation, followed by high-temperature calcination. However, traditional methods face the following technical bottlenecks: (1) Growth limit and particle size distribution: In wet synthesis, after the crystal particles grow to a certain size (usually above 15 μm), the growth rate slows down significantly, and they are prone to nucleation due to uneven local concentration, resulting in a large number of small particles, making it difficult to obtain large-particle products with uniform particle size distribution. (2) Contradiction between densification and structural integrity: During the calcination process with cobalt carbonate as a precursor, carbonate decomposes to produce a large amount of CO2 gas, and the instantaneous release of internal pressure easily leads to particle cracking and pulverization, making it difficult to obtain dense spherical particles with complete structure and low tap density; although the hard template method (such as dense spherical template) can guide growth, the removal of the template after calcination easily forms a hollow spherical shell structure. This structure has poor mechanical strength and is prone to cracking during subsequent electrode rolling, and the internal cavity results in limited improvement in tap density. (3) Problems of the traditional cobalt hydroxyl oxide route: Although carbonate decomposition can be avoided, pure cobalt hydroxyl oxide particles also face the problem of being difficult to densify and easy to agglomerate when grown to a large size.

[0004] Therefore, developing a new method for preparing cobalt tetroxide that can simultaneously achieve large particle size, high tap density, and excellent structural stability is a technical bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a method for synthesizing large-particle Co3O4 based on a porous carbon framework, thereby solving the technical problem that the preparation of cobalt tetroxide in the prior art cannot simultaneously take into account particle size, tap density and structural stability.

[0006] To achieve the above-mentioned technical objectives, the technical solution provided by the present invention is as follows: In a first aspect, the present invention provides a method for synthesizing large-particle Co3O4 based on a porous carbon framework, comprising the following steps: S1, mixing a porous carbon framework, cobalt salt, alkali, complexing agent, oxidant and solvent, and performing a co-precipitation reaction to obtain cobalt hydroxyoxide / carbon composite particles; wherein the amount of porous carbon framework added is 5-30% of the theoretical Co3O4 mass; S2, calcining the cobalt hydroxyoxide / carbon composite particles to obtain Co3O4 with D50≥10μm.

[0007] Preferably, in step S1, the average pore size of the porous carbon framework is between 0.5 and 5 μm.

[0008] Preferably, in step S1, the porous carbon framework includes expanded graphite or natural graphite that has been acid-washed and activated; the acid-washing and activation conditions are: using a 1-5 mol / L hydrochloric acid solution, acid washing treatment at 60-80°C for 2-4 hours.

[0009] Preferably, in step S1, the solvent includes water; mixing the porous carbon framework, cobalt salt, alkali, complexing agent, oxidant and solvent specifically includes: mixing the porous carbon framework with water to obtain mixture A, mixing the cobalt salt, complexing agent and water to obtain mixture B, and mixing the alkali with water to obtain alkali solution; under stirring conditions, adding mixture B, alkali solution and oxidant to mixture A and mixing evenly.

[0010] Furthermore, the concentration of porous carbon framework in mixture A is 25–40 g / L; the concentration of Co in mixture B is... 2+ The concentration is 120–140 g / L, and the concentration of the complexing agent is 1–3 g / L; the complexing agent includes ethylenediaminetetraacetic acid.

[0011] Preferably, in step S1, the oxidant includes at least one of air and hydrogen peroxide; the alkaline solution includes a sodium hydroxide solution with a concentration of 28-32 wt%; and the conditions for the coprecipitation reaction include: a pH value of 10.0-11.5, a reaction temperature of 60-80°C, and a stirring speed of 300-600 rpm.

[0012] Preferably, in step S1, after the co-precipitation reaction is completed, the cobalt hydroxyl oxide / carbon composite particles are obtained by aging, filtration, washing and drying.

[0013] Furthermore, the co-precipitation reaction is stopped when the product D50 particle size is 10-20 μm; the aging time is 1-3 h.

[0014] Preferably, in step S2, the calcination is carried out in an air atmosphere at 600–900°C for 2–8 hours.

[0015] Secondly, the present invention provides a Co3O4 synthesized by the above method, having a D50 particle size of 10–20 μm and a tap density ≥2.8 g / cm³.3 Furthermore, it contains nanoscale three-dimensional interconnected channels.

[0016] Compared with the prior art, the beneficial effects of the present invention include: This invention provides a method for synthesizing large-particle Co3O4 based on a porous carbon framework. By introducing a porous carbon framework with a specific pore structure as a sacrificial template and growth scaffold, this framework provides attachment sites and spatial confinement for the growth of cobalt hydroxyl oxide during the synthesis stage, guiding its formation of a composite structure. During the calcination stage, the carbon framework is slowly oxidized and removed, leaving uniformly distributed pores in situ, thus forming a porous but not hollow, dense structure. Simultaneously, this invention utilizes the physical support and confinement effect of the porous graphite framework to effectively solve the problems of explosive nucleation and difficulty in densification during the growth of cobalt hydroxyl oxide particles. It also avoids the particle breakage problem caused by violent gas release during the calcination of traditional cobalt carbonate precursors. The resulting cobalt tetroxide particles have a large particle size (10–21 μm) and a high tap density (≥2.8 g / cm³). 3 This invention achieves a balance between large particle size and high tap density, and the resulting cobalt tetroxide particles possess a uniform, nano-scale porous microstructure. This structure not only buffers the stress during lithium-ion insertion and extraction, improving the material's cycle stability, but also ensures the overall structural strength and high compaction density of the particles. The method provided by this invention uses readily available raw materials, operates under mild reaction conditions, exhibits good repeatability, demonstrates strong process controllability, and is easily industrialized. Attached Figure Description

[0017] Figure 1 This is an electron microscope image of the large-particle cobalt tetroxide prepared in Example 1 after calcination; Figure 2 This is a cross-sectional electron microscope image of the calcined large-particle cobalt tetroxide prepared in Example 1. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the invention, are intended to cover non-exclusive inclusion.

[0020] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0021] Due to the shortcomings of existing technologies in preparing large-particle cobalt tetroxide, such as difficulty in growth control, low density, easy formation of hollow structures, or brittleness during calcination, this invention provides a method for synthesizing large-particle Co3O4 based on a porous carbon framework. The process is controllable and can synthesize large-particle cobalt tetroxide with a uniform and dense internal structure.

[0022] In a first aspect, the present invention provides a method for synthesizing large-particle Co3O4 based on a porous carbon framework, comprising the following steps: S1, a porous carbon framework, cobalt salt, alkali, complexing agent, oxidant and solvent are mixed and subjected to a co-precipitation reaction to obtain cobalt hydroxyl oxide / carbon composite particles; wherein the amount of porous carbon framework added is 5-30% of the theoretical mass of Co3O4; S2, calcination of cobalt hydroxyoxide / carbon composite particles yields Co3O4 with D50≥10μm.

[0023] This invention introduces a porous carbon framework with a specific pore structure as a sacrificial template and growth scaffold. During the synthesis stage, the framework provides attachment points and spatial confinement for the growth of cobalt hydroxyl oxide, guiding it to form a composite structure. During the calcination stage, the carbon framework is slowly oxidized and removed, leaving uniformly distributed pores in situ, thereby forming a porous but not hollow dense structure.

[0024] Furthermore, this invention controls the amount of porous carbon framework added. If the amount added is too small, the support function will be insufficient, and the product structure will tend to grow without a template, making it easy to become loose. If the amount added is too large, the economic efficiency will be poor, and the residual ash after calcination may affect the purity of the product.

[0025] In some embodiments, in step S1, the average pore size of the porous carbon framework is between 0.5 and 5 μm. When the pore size of the porous carbon framework is less than 0.5 μm, the small pore size is not conducive to the diffusion of reactant ions and product filling, and the resistance to gas escape during calcination is large; when the pore size is greater than 5 μm, the supporting effect of the framework is weakened, and excessively large cavities are easily formed after calcination, affecting the particle density and strength. By controlling it within this pore size range, an effective confinement can be provided during the growth stage, and an ideal uniform porous structure can be formed after calcination.

[0026] In some embodiments, in step S1, the porous carbon framework includes expanded graphite or natural graphite that has been acid-washed and activated. This invention utilizes acid washing and activation of natural graphite to expand its interlayer pores, or directly selects commercially available porous graphite materials such as expanded graphite, which are widely available and inexpensive.

[0027] Furthermore, the pickling activation conditions are as follows: use a 1-5 mol / L hydrochloric acid solution and pickle at 60-80℃ for 2-4 hours.

[0028] In some embodiments, in step S1, the solvent includes water; mixing the porous carbon framework, cobalt salt, alkali, complexing agent, oxidant and solvent specifically includes: mixing the porous carbon framework with water to obtain mixture A, mixing the cobalt salt, complexing agent and water to obtain mixture B, and mixing the alkali with water to obtain alkali solution; under stirring conditions, adding mixture B, alkali solution and oxidant to mixture A and mixing evenly.

[0029] Furthermore, the concentration of porous carbon framework in mixture A is 25–40 g / L; the concentration of Co in mixture B is... 2+ The concentration is 120–140 g / L, and the concentration of the complexing agent is 1–3 g / L; the complexing agent includes ethylenediaminetetraacetic acid (EDTA).

[0030] In some embodiments, in step S1, the oxidant includes at least one of air and hydrogen peroxide.

[0031] Furthermore, when the oxidant is hydrogen peroxide, its addition amount is 1 to 10% of the mass of the cobalt salt.

[0032] In some embodiments, in step S1, the alkaline solution comprises a sodium hydroxide solution with a concentration of 28–32 wt%; the conditions for the coprecipitation reaction include: a pH value of 10.0–11.5, a reaction temperature of 60–80°C, and a stirring speed of 300–600 rpm. This invention, by controlling the conditions of the coprecipitation reaction, enables the generated cobalt hydroxyoxide (CoOOH) to crystallize in situ and grow on the surface and inside the pores of a porous carbon framework, forming cobalt hydroxyoxide / carbon composite particles.

[0033] In some embodiments, in step S1, after the co-precipitation reaction is completed, the cobalt hydroxyl oxide / carbon composite particles are obtained by aging, filtration, washing and drying.

[0034] Furthermore, the co-precipitation reaction is stopped when the product D50 particle size is 10-20 μm; the aging time is 1-3 h. In this invention, aging helps the crystals develop more completely and the structure is more stable; without the aging step, some tiny crystals may not be fully attached, resulting in a slightly wider particle size distribution (increased D90-D10 values).

[0035] In some embodiments, in step S2, calcination is performed in an air atmosphere at 600–900°C for 2–8 hours. During this calcination process, the carbon skeleton is gradually oxidized to CO2 and slowly removed, while cobalt hydroxyl oxide is converted to cobalt tetroxide (Co3O4). The removal of the carbon skeleton, such as graphite, leaves behind a uniformly distributed network of internal pores derived from the original skeleton pores, ultimately yielding a large-particle cobalt tetroxide product.

[0036] Secondly, the present invention provides a Co3O4 synthesized by the above method, having a D50 particle size of 10–20 μm and a tap density ≥2.8 g / cm³. 3 Furthermore, it contains nanoscale three-dimensional interconnected channels.

[0037] The cobalt tetroxide prepared by this invention has a high tap density while maintaining a large particle size. It can be sintered with a lithium source to produce lithium cobalt oxide cathode material for use in lithium-ion batteries.

[0038] The main mechanism of action and advantages of this invention are as follows: (1) This invention uses porous graphite and other carbon frameworks as rigid supports to effectively suppress agglomeration and explosive nucleation during the growth of cobalt hydroxyl oxide, guiding its dense packing, thereby enabling the stable synthesis of large particles with a D50 of 10-20 μm. The uniform porous structure (non-hollow) formed after calcination allows the particles to maintain a large particle size while possessing a high tap density (≥2.8 g / cm³). 3 This achieves a balance between large particle size and high tap density.

[0039] (2) Unlike the “hollow” structure formed by the traditional hard template method, the present invention uses a through-type porous network as a template. After calcination, the interior of the product consists of interconnected, uniformly sized micro-channels. This unique uniform porous microstructure can buffer the stress during lithium ion insertion and extraction, improve the material’s cycle stability, and ensure the overall structural strength and high compaction density of the particles.

[0040] (3) Compared with the violent release of CO2 during the calcination of cobalt carbonate precursor, the carbon skeleton such as graphite is gradually oxidized in the air, and the gas release is slow and mild, which avoids the particle cracking caused by the sudden increase of internal pressure, thus ensuring the integrity of the product particles and high yield, and solving the problem of particle breakage during the calcination process.

[0041] (4) The raw materials of the method of the present invention are readily available, the reaction conditions are mild, the repeatability is good, the process is highly controllable, and it is easy to industrialize. It is especially suitable for large-scale production of high-performance lithium-ion battery cathode material precursors.

[0042] The present invention will be further described in detail below through specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments used that do not specify the manufacturer are all conventional products that can be obtained commercially.

[0043] Example 1 A method for synthesizing large-particle Co3O4 based on a porous carbon framework includes the following steps: S1, Synthesis of cobalt hydroxyoxide / carbon composite particles: S101, Pretreatment of porous graphite framework: 1000g of natural flake graphite (initial particle size approximately 12μm) was added to 5000mL of 2mol / L dilute hydrochloric acid solution (liquid-solid ratio 5:1), and the mixture was stirred and acid-washed at 70℃ for 3 hours. After acid washing, it was washed with deionized water until neutral, and dried at 110℃ to obtain the acid-activated porous graphite framework. BET testing showed that its average pore size was approximately 1.2μm (meeting the requirement of 0.5-5μm).

[0044] S102, Preparation of the coprecipitation reaction system: Add 25L of deionized water to the reactor, then add 800g of the pretreated porous graphite framework (approximately 20% of the expected cobalt tetroxide yield, used as a growth scaffold and subsequent sacrificial template); start stirring at 500 rpm and heat to 70℃; prepare a cobalt chloride solution (Co... 2+ A 130 g / L sodium hydroxide solution (containing 2 g / L EDTA as a complexing agent) and a 30 wt% sodium hydroxide solution were added dropwise to the reactor. The pH of the reaction system was precisely controlled to be stable at 11.0 by adjusting the flow rate of the alkali solution.

[0045] S103, coprecipitation reaction: The reaction temperature was maintained at 70℃, compressed air was introduced throughout the process (flow rate 10 kg / h), and hydrogen peroxide with a concentration of 10% was added intermittently. The total amount of hydrogen peroxide added was about 3% of the mass of the cobalt salt added, in order to assist oxidation and ensure the conversion of Co(II) to Co(III); the reaction was continued and the particle size was monitored online. When the laser particle size analyzer showed that the product D50 reached 16.0 μm, all feed was stopped, the product was allowed to stand, cooled to room temperature and aged for 2 hours, and the product was filtered, washed with deionized water, and dried at 120℃ to obtain gray-black cobalt hydroxyl oxide / graphite composite particles.

[0046] S2, Calcination: The cobalt hydroxyl oxide / graphite composite particles were placed in a muffle furnace and heated to 700°C at a rate of 2°C / min under static air atmosphere, and then calcined at this temperature for 6 hours. After natural cooling, black cobalt tetroxide powder was obtained.

[0047] Example 2 Compared to Example 1, the difference lies in the carbon skeleton and some parameters; the other steps and conditions are the same as in Example 1. The differences are: Commercially available expanded porous graphite (pore size 2-3μm, framework size about 15μm) was directly selected as the porous framework, and the amount added was 15% of the expected cobalt tetroxide yield; the reaction pH was controlled at 10.5, and the co-precipitation reaction was stopped when the D50 reached 20.5μm; calcination was carried out at 750℃ for 5 hours.

[0048] Comparative Example 1 (without graphite framework) Compared with Example 1, the difference is that no carbon skeleton is added; the other steps and conditions are the same as in Example 1.

[0049] Comparative Example 2 (using non-porous graphite) Compared with Example 1, the difference is that: unactivated dense artificial graphite particles (pore size <0.1μm) are used instead of porous graphite, with an addition amount of 20%; other steps and conditions are the same as in Example 1.

[0050] Comparative Example 3 (using the cobalt carbonate route) Following traditional methods, spherical cobalt carbonate with a D50 of approximately 16 μm was synthesized and then calcined at 700 °C to obtain cobalt tetroxide.

[0051] Performance testing (1) The surface and cross-sectional SEM scans of the cobalt tetroxide obtained in Example 1 above were performed, and the results are as follows: Figures 1-2 As shown.

[0052] Figures 1-2 The microstructure shows: Figure 1 (Surface morphology) shows that the particles are spherical or near-spherical, and the surface is composed of densely packed primary particles. Figure 2 (Cross-section morphology) Clearly shows that the interior of the particles has a uniformly distributed sponge-like porous structure without large hollow cavities, confirming the characteristics of being porous but not hollow.

[0053] The specific surface area and pore size of cobalt tetroxide obtained in Example 1 were determined by BET testing: the specific surface area was 4.5 m². 2 / g, with a pore size distribution concentrated in the 30-50nm range, formed by the derivation of macropores in the graphite framework and the accumulation of primary particles.

[0054] (2) The cobalt tetroxide obtained in Examples 1-2 and Comparative Examples 1-3 were tested, including particle size (tested by laser particle size analyzer) and tap density; the results are shown in Table 1.

[0055] Table 1. Particle size and tap density of cobalt tetroxide obtained in Examples 1-2 and Comparative Examples 1-3

[0056] As shown in Table 1, the cobalt tetroxide particles prepared in Examples 1-2 of the present invention have large particle size, high tap density, and well-developed three-dimensional interconnected pore structure inside the particles.

[0057] In contrast, Comparative Example 1 did not use a graphite framework, making the reaction difficult to control. The product contained a large number of fine particles (D10 < 2 μm) and a small number of large particles (D90 > 30 μm), resulting in an extremely wide particle size distribution and a tap density of only 1.8 g / cm³. 3 The particles were severely broken after calcination.

[0058] In Comparative Example 2, unactivated dense artificial graphite particles were used, with cobalt hydroxyl oxide only coating the surface of the graphite and unable to penetrate the interior. The calcined product had a hollow spherical shell structure, poor particle strength, and crumbled easily with slight grinding.

[0059] Comparative Example 3 uses the traditional method to prepare cobalt tetroxide by calcining spherical cobalt carbonate. The resulting product has severe surface cracking, poor sphericity, and the particles are easily pulverized.

[0060] The comparison between the above embodiments and comparative examples fully demonstrates the key role and irreplaceable nature of porous graphite framework and its specific pore structure in obtaining large-particle-size, high-tap-density, and uniform porous cobalt tetroxide in the method of the present invention.

[0061] In summary, the method for synthesizing large-particle Co3O4 based on a porous carbon framework provided by this invention first prepares or selects a porous graphite framework with a specific pore size range as a sacrificial template and growth scaffold. In a co-precipitation reaction system, cobalt hydroxyl oxide is grown in situ and fills the pores and surface of the porous framework to form composite particles. Finally, the graphite template is removed by calcination to obtain large-particle cobalt tetroxide with a particle size of 10–21 μm, a uniform porous rather than hollow internal structure, and high tap density. This invention utilizes the physical support and confinement effect of the porous graphite framework to effectively solve the problems of easy nucleation and difficulty in densification during the growth of cobalt hydroxyl oxide particles. It also avoids the particle breakage problem caused by violent gas release during the calcination of traditional cobalt carbonate precursors. The resulting cobalt tetroxide product is particularly suitable for preparing high-taper-density, high-energy-density lithium cobalt oxide cathode materials.

[0062] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for synthesizing large-particle Co3O4 based on a porous carbon framework, characterized in that, Includes the following steps: S1, a porous carbon framework, cobalt salt, alkali, complexing agent, oxidant and solvent are mixed and subjected to a co-precipitation reaction to obtain cobalt hydroxyl oxide / carbon composite particles; wherein the amount of porous carbon framework added is 5-30% of the theoretical mass of Co3O4; S2, the cobalt hydroxyoxide / carbon composite particles are calcined to obtain Co3O4 with D50≥10μm.

2. The method for synthesizing large-particle Co3O4 based on a porous carbon framework according to claim 1, characterized in that, In step S1, the average pore size of the porous carbon framework is between 0.5 and 5 μm.

3. The method for synthesizing large-particle Co3O4 based on a porous carbon framework according to claim 1, characterized in that, In step S1, the porous carbon framework includes expanded graphite or natural graphite that has been acid-washed and activated. The conditions for acid washing activation are as follows: use a 1-5 mol / L hydrochloric acid solution and acid wash at 60-80℃ for 2-4 hours.

4. The method for synthesizing large-particle Co3O4 based on a porous carbon framework according to claim 1, characterized in that, In step S1, the solvent includes water; The process of mixing the porous carbon framework, cobalt salt, alkali, complexing agent, oxidant, and solvent specifically includes: mixing the porous carbon framework with water to obtain mixture A, mixing the cobalt salt, complexing agent, and water to obtain mixture B, and mixing the alkali with water to obtain an alkali solution; and adding mixture B, alkali solution, and oxidant to mixture A under stirring conditions and mixing them evenly.

5. The method for synthesizing large-particle Co3O4 based on a porous carbon framework according to claim 4, characterized in that, The concentration of the porous carbon framework in mixture A is 25–40 g / L; the concentration of Co in mixture B is... 2+ The concentration is 120–140 g / L, and the concentration of the complexing agent is 1–3 g / L; the complexing agent includes ethylenediaminetetraacetic acid.

6. The method for synthesizing large-particle Co3O4 based on a porous carbon framework according to claim 4, characterized in that, In step S1, the oxidant includes at least one of air and hydrogen peroxide; The alkaline solution includes a sodium hydroxide solution with a concentration of 28–32 wt%. The conditions for the coprecipitation reaction include: pH value of 10.0 to 11.5, reaction temperature of 60 to 80°C, and stirring speed of 300 to 600 rpm.

7. The method for synthesizing large-particle Co3O4 based on a porous carbon framework according to claim 1, characterized in that, In step S1, after the co-precipitation reaction is completed, the particles are aged, filtered, washed and dried to obtain cobalt hydroxyoxide / carbon composite particles.

8. The method for synthesizing large-particle Co3O4 based on a porous carbon framework according to claim 7, characterized in that, The coprecipitation reaction was terminated when the product D50 particle size was 10-20 μm. The aging time is 1 to 3 hours.

9. The method for synthesizing large-particle Co3O4 based on a porous carbon framework according to claim 1, characterized in that, In step S2, the calcination is carried out in an air atmosphere at 600-900°C for 2-8 hours.

10. The Co3O4 synthesized by the method according to any one of claims 1-9, characterized in that, The Co3O4 has a D50 particle size of 10–20 μm and a tap density ≥2.8 g / cm³. 3 Furthermore, it contains nanoscale three-dimensional interconnected channels.

Images