Macroscopic preparation method of atomic level metal dispersed spherical carbon shell for zinc-air battery

Abstract

The application discloses a macro preparation method of atomic metal dispersed spherical carbon shell for zinc-air batteries, and belongs to the technical field of macro preparation of atomic metal dispersed spherical carbon shell materials and battery catalysts. In view of the problems of existing metal carbon-nitrogen materials, such as easy agglomeration of active sites, insufficient catalytic activity, and great difficulty in large-scale preparation, the application performs normal-temperature polycondensation of terephthaldehyde, TEOS and amine compounds in methanol, performs calcination on the product at 900 DEG C in a nitrogen atmosphere after washing and drying, removes the silica template by using 10% hydrofluoric acid for normal-temperature etching for 24 hours, loads the spherical carbon shell in DMF by normal-temperature stirring with phthalocyanine compounds for 12 hours, and finally obtains the target material. The method is simple and controllable, has low raw material cost, is safe, and can realize kilogram-level macro preparation. The obtained material has excellent metal atom dispersity and outstanding electrochemical catalytic performance, and can significantly improve the specific capacity, rate performance and cycle stability when applied to zinc-air batteries.

Description

Technical Field

[0001] This invention belongs to the field of mass production of atomically dispersed spherical carbon shell materials and battery catalyst technology, specifically relating to a method for mass production of atomically dispersed spherical carbon shells for zinc-air batteries. Background Technology

[0002] Zinc-air batteries are metal-air batteries that use zinc as the negative electrode active material and oxygen from the air as the positive electrode active material. They generate electricity through the electrochemical reaction of zinc and oxygen, possessing advantages such as high energy density, low cost, and environmental friendliness, and are considered one of the potential technologies for future energy storage and electric transportation. Phthalocyanine compounds, when doped into carbonaceous materials, exhibit atomic-level dispersion of the metal component, characterized by highly separated unsaturated metal sites and strong matrix interactions, resulting in superior catalytic performance compared to their metal clusters. Currently, their catalytic effects have been extensively studied in heterogeneous catalysis and electrochemical catalysis. Phthalocyanine compounds, such as iron phthalocyanine (FePc), possess unique Fe-N4 sites, and most phthalocyanine compounds can interact with carbonaceous substrates through... π-π Interactions form stable structures with metal atoms dispersed at the atomic level. Based on this theory, many types of metal-nitrogen-carbon materials have been successfully obtained through simple methods, with central metal atoms adaptable to the requirements of different catalytic reactions.

[0003] However, it is difficult to balance the density and dispersion of active sites, and high metal loading can easily lead to agglomeration and reduce atom utilization. Secondly, the bifunctional catalytic activity is insufficient, and it is difficult for a single material to simultaneously optimize the kinetics of oxygen reduction (ORR) and oxygen evolution reaction (OER). In addition, the long-term cycling stability is poor, and the problems of metal site dissolution and carbon matrix corrosion in alkaline environment are prominent. The cycle life of most metal nitrogen and carbon catalysts is less than 500 hours. Finally, large-scale preparation faces challenges. The high-temperature pyrolysis process (>800°C) has high energy consumption and batch consistency is difficult to control.

[0004] Based on this, the present invention provides a method for the large-scale preparation of atomically dispersed spherical carbon shells for zinc-air batteries. Summary of the Invention

[0005] This invention provides a method for the large-scale preparation of atomically dispersed spherical carbon shells for zinc-air batteries. The method involves mixing and reacting an aldehyde-amine condensate precursor with a spherical silica precursor, causing the condensate to coat the surface of the spherical silica. After cleaning, centrifugation, drying, and high-temperature calcination, the silica is removed by etching with hydrofluoric acid to obtain the spherical carbon shell. Finally, a phthalocyanine compound is attached to the carbon shell material to obtain an atomically dispersed spherical carbon shell material.

[0006] The technical solution adopted by this invention to solve its technical problem is: a method for the large-scale preparation of atomically dispersed spherical carbon shells for zinc-air batteries, comprising the following steps: S1 dissolves terephthalaldehyde and TEOS in methanol, stirs and sonicates until completely dissolved, and obtains a clear solution; S2 dissolves amine compounds in methanol, stirs, and sonicates until homogeneous to obtain a clear solution; S3 adds the mixed solution obtained in S1 to the mixed solution obtained in S2 and stirs at room temperature; S4 involves washing, centrifuging, and drying the reaction product multiple times to obtain a dried sample. S5 involves placing the dried sample in a tube furnace and calcining it at high temperature under inert gas protection. S6 disperses the calcined product in a hydrofluoric acid solution and stirs it at room temperature; S7 repeatedly cleaned, centrifuged and dried the sample after hydrofluoric acid etching to obtain spherical carbon shell material. S8 dissolved spherical carbon shell material and phthalocyanine compounds in DMF and stirred at room temperature; S9 was subjected to multiple washing, centrifugation and drying of the reaction product to obtain atomically dispersed spherical carbon shell material.

[0007] Preferably, the amine compound in step S2 is any one or more of ethylenediamine, hexamethylenediamine, p-phenylenediamine, and melamine.

[0008] Preferably, the reaction time for stirring at room temperature in step S3 is 8 hours.

[0009] Preferably, in the large-scale preparation method according to claim 1, the washing, centrifugation, and drying in step S4 specifically refer to: Cleaning: Clean with methanol three times, then clean with anhydrous ethanol; Centrifugation: Anhydrous ethanol is used as the centrifugation solvent; Drying: at 60℃ for 10-12 hours.

[0010] Preferably, in the mass production method according to claim 1, the high-temperature calcination in step S5 specifically comprises: The inert gas is nitrogen; The calcination temperature was 900℃, the heating rate was 5℃ / min, and the calcination time was 1 hour.

[0011] Preferably, in the mass production method according to claim 1, the concentration of the hydrofluoric acid solution in step S6 is 10%, and the stirring time at room temperature is 24 hours.

[0012] Preferably, in the large-scale preparation method according to claim 1, the washing, centrifugation, and drying in step S7 specifically refer to: Cleaning: Rinse three times with deionized water, then rinse with anhydrous ethanol; Centrifugation: Anhydrous ethanol is used as the centrifugation solvent; Drying: at 60℃ for 10-12 hours.

[0013] Preferably, in the mass production method according to claim 1, the phthalocyanine compound in step S8 is any one or more of iron phthalocyanine, aluminum phthalocyanine, copper phthalocyanine, tin phthalocyanine, cobalt phthalocyanine (II), zinc phthalocyanine, copper hexadecyl phthalocyanine, titanium phthalocyanine, nickel perfluorophthalocyanine (II), and lead phthalocyanine, and the stirring time at room temperature is 12 hours.

[0014] Preferably, in the large-scale preparation method according to claim 1, the washing, centrifugation, and drying in step S9 specifically refer to: Cleaning: Clean with anhydrous ethanol; Centrifugation: Anhydrous ethanol is used as the centrifugation solvent; Drying: at 60℃ for 10-12 hours.

[0015] Preferably, an atomically dispersed spherical carbon shell material prepared by the method described in any one of claims 1-9.

[0016] Preferably, a zinc-air battery comprising the atomically dispersed spherical carbon shell material of claim 10.

[0017] The advantages of this invention are: 1. The preparation process is simple and controllable, making it suitable for large-scale industrial production. This invention employs a process route combining room-temperature liquid-phase polycondensation with high-temperature calcination. All reactions are carried out under normal pressure, eliminating the need for complex equipment such as high pressure, vacuum, and plasma. The raw materials are all readily available industrial-grade chemicals (amines such as terephthalaldehyde and ethylenediamine, TEOS, and phthalocyanine compounds), with no dependence on precious metals. The raw material cost is significantly lower than existing methods for preparing single-atom catalysts. The preparation steps are clear and repeatable, with good batch consistency, and the yield of a single batch can be easily scaled up to the kilogram level. This invention solves the pain points of existing atomic-level dispersed carbon materials, such as high difficulty, high cost, and difficulty in industrialization.

[0018] 2. The preparation process is safe and environmentally friendly, with a low operational threshold. The entire preparation process does not involve the extensive use of highly toxic or strong oxidizing reagents. The hydrofluoric acid etching step uses a low-concentration (10%) system at room temperature, and the residue can be completely removed by repeated deionized water rinsing. All post-processing steps are routine centrifugation and drying operations, requiring no special protective facilities or professional operating skills. Both laboratories and factories can easily implement this process, significantly improving the safety and environmental friendliness of the production process.

[0019] 3. The material structure is precisely controllable, with excellent atomic-level metal dispersion. The morphology, size, and wall thickness of the carbon shell were precisely controlled using a spherical silica hard template method to obtain a uniform hollow spherical structure with a large specific surface area and well-developed pore structure; phthalocyanine compounds were used. π-π The stacked loading method utilizes the strong interaction between the phthalocyanine ring and the carbon matrix to achieve uniform dispersion of metal atoms at the single-atom level, effectively avoiding the aggregation of metal clusters during high-temperature processes, maximizing the number of active sites and atomic utilization, and laying the structural foundation for excellent electrochemical performance.

[0020] 4. Excellent electrochemical catalytic performance, suitable for zinc-air battery applications. The prepared atomically dispersed spherical carbon shell material exhibits outstanding catalytic activity for the oxygen reduction reaction (ORR), with high half-wave potential, large limiting diffusion current, and fast kinetic response. It also has excellent resistance to methanol poisoning, maintaining stable catalytic activity even in complex electrolyte environments containing methanol, thus avoiding performance degradation caused by fuel permeation during battery operation.

[0021] 5. The overall performance of the battery is significantly improved, and the cycle stability is good. Applying this material to the air electrode catalyst of zinc-air batteries significantly reduces the polarization resistance of the electrode and improves the battery's output power density. The battery exhibits high specific capacity, excellent rate performance, and long-cycle stability, meeting the energy storage and power application requirements of various scenarios such as portable electronic devices and low-speed electric vehicles. The spherical carbon shell's carbon matrix possesses good chemical stability and conductivity, effectively protecting the metal active sites from dissolution and corrosion in strongly alkaline electrolytes. The hollow structure provides a buffer space for volume changes during charge and discharge, preventing the collapse of the material structure and thus significantly extending the battery's cycle life. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 Flowchart of the preparation method of this invention (using ethylenediamine as an example for amines and iron phthalocyanine as an example for phthalocyanines); Figure 2 Scanning electron microscope image of atomically dispersed metallic spherical carbon shell material; Figure 3 Transmission electron microscopy image of an atomically dispersed metallic spherical carbon shell material; Figure 4 Elemental distribution diagram of atomically dispersed metallic spherical carbon shell materials; Figure 5 X-ray diffraction pattern of atomically dispersed metallic spherical carbon shell material; Figure 6 Raman spectrum of atomically dispersed metallic spherical carbon shell material; Figure 7 X-ray photoelectron spectrum of atomically dispersed metallic spherical carbon shell material; Figure 8 Comparison of ORR catalytic performance between atomically dispersed spherical carbon shell materials and other catalysts; Figure 9 Comparison of methanol resistance properties of atomically dispersed metallic spherical carbon shell materials; Figure 10 A schematic diagram of a zinc-air battery containing this material; Figure 11 Specific capacity curve of zinc-air battery; Figure 12 Photographs of the mass production of atomically dispersed spherical carbon shell materials. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and 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.

[0025] The specific preparation steps of this invention are as follows: 1. Preparation of precursor solution: Dissolve terephthalaldehyde and TEOS in methanol, stir and sonicate until clear; separately dissolve amine compounds in methanol, stir and sonicate until homogeneous.

[0026] 2. Polycondensation reaction: Mix the two solutions and stir at room temperature for 8 hours.

[0027] 3. Post-processing: The reaction product was washed three times with methanol, centrifuged with anhydrous ethanol, and dried at 60°C for 10-12 hours.

[0028] 4. High-temperature calcination: The dried sample was calcined at 900℃ for 1 hour under nitrogen protection, with a heating rate of 5℃ / min.

[0029] 5. Template etching: The calcined product was dispersed in a 10% hydrofluoric acid solution and stirred at room temperature for 24 hours; after washing three times with deionized water, centrifuging with anhydrous ethanol, and drying at 60℃ for 10-12 hours, spherical carbon shells were obtained.

[0030] 6. Metal loading: Dissolve the spherical carbon shell and phthalocyanine compound in DMF and stir at room temperature for 12 hours; wash with anhydrous ethanol, centrifuge, and dry at 60°C for 10-12 hours to obtain the target product.

[0031] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0032] Example 1 1. Add 1 mmol of terephthalaldehyde and 2 mL of LTEOS to 50 mL of methanol, stir for 30 min, and sonicate for 10 min until completely dissolved to obtain clear solution A.

[0033] 2. Add 1 mmol of ethylenediamine to 20 mL of methanol, stir for 20 min, and sonicate for 5 min until the mixture is homogeneous to obtain clear solution B.

[0034] 3. Slowly add clarified solution A dropwise to clarified solution B and stir at room temperature for 8 hours.

[0035] 4. After the reaction is complete, centrifuge the product at 8000 rpm for 10 min, discard the supernatant; add methanol and sonicate to disperse, centrifuge again, repeat 3 times; finally, centrifuge once with anhydrous ethanol.

[0036] 5. Place the centrifuged product in a vacuum drying oven and dry at 60°C for 12 hours to obtain a dried sample.

[0037] 6. Place the dried sample in a tube furnace, purge with nitrogen for protection, heat to 900°C at a rate of 5°C / min, hold at that temperature for 1 hour, and allow to cool naturally to room temperature.

[0038] 7. Disperse the calcined product in 100 mL of 10% hydrofluoric acid solution, stir at room temperature for 24 hours, and etch away the silica template.

[0039] 8. After etching, centrifuge the product at 10,000 rpm for 15 min, discard the supernatant; add deionized water and sonicate to disperse, then centrifuge again, repeating 3 times; finally, centrifuge once with anhydrous ethanol.

[0040] 9. Place the product in a vacuum drying oven and dry at 60°C for 12 hours to obtain spherical carbon shell material.

[0041] 10. Add 0.1g of spherical carbon shell material and 0.05g of iron phthalocyanine to 50ml of LDM and stir at room temperature for 12 hours.

[0042] 11. After the reaction was completed, the product was centrifuged at 10,000 rpm for 15 min, washed three times with anhydrous ethanol, and dried at 60 °C for 12 hours to obtain iron atom-level dispersed spherical carbon shell material.

[0043] Example 2 The difference from Example 1 is that in step 2, the amine compound is replaced with hexamethylenediamine, and in step 10, the phthalocyanine compound is replaced with cobalt(II) phthalocyanine. The remaining steps and parameters are the same as in Example 1.

[0044] Example 3 The difference from Example 1 is that in step 2, the amine compound is replaced with p-phenylenediamine, and in step 10, the phthalocyanine compound is replaced with copper phthalocyanine. The remaining steps and parameters are the same as in Example 1.

[0045] Example 4 The difference from Example 1 is that in step 2, the amine compound is replaced with melamine, and in step 10, the phthalocyanine compound is replaced with zinc phthalocyanine. The remaining steps and parameters are the same as in Example 1.

[0046] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for the large-scale preparation of atomically dispersed spherical carbon shells for zinc-air batteries, characterized in that, Includes the following steps: S1 dissolves terephthalaldehyde and TEOS in methanol, stirs and sonicates until completely dissolved, and obtains a clear solution; S2 dissolves amine compounds in methanol, stirs, and sonicates until homogeneous to obtain a clear solution; S3 adds the mixed solution obtained in S1 to the mixed solution obtained in S2 and stirs at room temperature; S4 involves washing, centrifuging, and drying the reaction product multiple times to obtain a dried sample. S5 involves placing the dried sample in a tube furnace and calcining it at high temperature under inert gas protection. S6 disperses the calcined product in a hydrofluoric acid solution and stirs it at room temperature; S7 repeatedly cleaned, centrifuged and dried the sample after hydrofluoric acid etching to obtain spherical carbon shell material. S8 dissolved spherical carbon shell material and phthalocyanine compounds in DMF and stirred at room temperature; S9 was subjected to multiple washing, centrifugation and drying of the reaction product to obtain atomically dispersed spherical carbon shell material.

2. The mass production method according to claim 1, characterized in that, The amine compound mentioned in step S2 is any one or more of ethylenediamine, hexamethylenediamine, p-phenylenediamine, and melamine.

3. The mass production method according to claim 1, characterized in that, The reaction time for stirring at room temperature in step S3 is 8 hours.

4. The mass production method according to claim 1, characterized in that, The washing, centrifugation, and drying steps in step S4 specifically refer to: Cleaning: Clean with methanol three times, then clean with anhydrous ethanol; Centrifugation: Anhydrous ethanol is used as the centrifugation solvent; Drying: at 60℃ for 10-12 hours.

5. The mass production method according to claim 1, characterized in that, The high-temperature roasting mentioned in step S5 specifically refers to: The inert gas is nitrogen; The calcination temperature was 900℃, the heating rate was 5℃ / min, and the calcination time was 1 hour.

6. The mass production method according to claim 1, characterized in that, The concentration of the hydrofluoric acid solution in step S6 is 10%, and the stirring time at room temperature is 24 hours.

7. The mass production method according to claim 1, characterized in that, The washing, centrifugation, and drying steps in step S7 specifically include: Cleaning: Rinse three times with deionized water, then rinse with anhydrous ethanol; Centrifugation: Anhydrous ethanol is used as the centrifugation solvent; Drying: at 60℃ for 10-12 hours.

8. The mass production method according to claim 1, characterized in that, The phthalocyanine compound mentioned in step S8 is any one or more of iron phthalocyanine, aluminum phthalocyanine, copper phthalocyanine, tin phthalocyanine, cobalt phthalocyanine (II), zinc phthalocyanine, copper hexadecyl phthalocyanine, titanium phthalocyanine, nickel perfluorophthalocyanine (II), and lead phthalocyanine, and the stirring time at room temperature is 12 hours.

9. The mass production method according to claim 1, characterized in that, The washing, centrifugation, and drying steps in step S9 specifically include: Cleaning: Clean with anhydrous ethanol; Centrifugation: Anhydrous ethanol is used as the centrifugation solvent; Drying: at 60℃ for 10-12 hours.

10. An atomically dispersed spherical carbon shell material prepared by the method according to any one of claims 1-9.

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