Carbon-based iodine carrier material containing three metal atom catalytic centers as well as preparation method and application of carbon-based iodine carrier material

Abstract

The invention relates to the technical field of iodine carrier materials, in particular to a carbon-based iodine carrier material containing a three-metal-atom catalytic center and a preparation method and application of the carbon-based iodine carrier material. The preparation method of the three-metal atom catalytic center carbon-based iodine carrier material comprises the following steps: dispersing Ketjen black in a solvent to obtain a dispersion liquid; adding cobalt acetate, 1, 3, 5-triazine-2, 4-diamine and 1, 1 '-carbonyl bis-imidazole into the dispersion liquid, performing ultrasonic treatment, and then performing heating reaction; and after the reaction is completed, naturally cooling the reaction liquid to room temperature, filtering, washing and drying to obtain the carbon-based iodine carrier material containing the three-metal-atom catalytic center. The carbon-based iodine carrier material designed by the invention has efficient catalytic active sites, optimizes the conversion process of multi-iodide ions, and significantly improves the stability and high rate performance of the carbon-based iodine carrier material, thereby achieving synergistic improvement of iodine positive electrode performance.

Description

Technical Field

[0001] This invention relates to the field of iodine support material technology, and in particular to a carbon-based iodine support material containing a trimetallic atom catalytic center, its preparation method, and its application. Background Technology

[0002] Zinc-iodine batteries are known for their high specific capacity (211 mAh g). 1 ), and a higher redox potential (approximately 0.54 V vs. H). + Zinc-iodine batteries have attracted widespread attention due to their advantages such as good safety, abundant and inexpensive zinc and iodine resources, and high cost. However, they still face some challenges, such as the low conductivity of iodine and polyiodide ions, the easy solubility of reaction intermediates in the electrolyte, the slow conversion rate of polyiodide ions, and the shuttle effect.

[0003] Ideal iodine support materials should possess high electronic conductivity and a hierarchical porous structure. High electronic conductivity promotes rapid electron transport in electrochemical reactions, while the hierarchical porous structure can effectively support iodine-active substances and inhibit the dissolution and diffusion of intermediate polyiodide ions through physical confinement, thereby improving the utilization rate of elemental iodine and suppressing the shuttle effect. Carbon materials, due to their excellent conductivity, abundant microporous structures, and relatively convenient acquisition methods, have become ideal candidates for iodine support materials. However, carbon materials typically lack active catalytic sites and have relatively stable surface chemistry, making it difficult for them to effectively adsorb polyiodide ion intermediates, thus limiting their ability to regulate the catalytic reaction process.

[0004] In the conversion of iodide ions, key intermediates include iodide anions, elemental iodine, iodide tri-antions, and iodide penta-antions. Carbon-based single-atom catalysts (SACs) have become a research hotspot for iodide ion conversion reactions due to their atomically dispersed catalytic sites, high conductivity, and tunable coordination environment. However, the catalytic efficiency of SACs is limited by the linear scaling relationship of adsorption energies, making it difficult to independently optimize the adsorption energies of multiple intermediates, which to some extent restricts the improvement of reaction kinetics. As an extension of SACs, carbon-based diatomic catalysts (DACs) have attracted much attention in the study of polyiodide ion conversion processes because they can adjust the linear scaling relationship of adsorption energies. However, the catalytic performance of DACs has not yet fully met expectations, mainly due to the spatial fixation of bimetallic sites. This limitation restricts the range of adjustment of the adsorption energies of intermediates such as iodide tri-antions and iodide penta-antions, making it impossible to achieve completely independent optimization of adsorption energies.

[0005] Trimetallic atom catalysts (TACs) offer a novel approach to addressing the aforementioned challenges by further modulating the linear scaling relationship of adsorption energies through synergistic effects between metal atoms. Through the synergistic interaction of adjacent metal centers, TACs can regulate the charge distribution of intermediate products, thereby optimizing the kinetics of catalytic reactions and significantly enhancing catalytic activity. Furthermore, TACs demonstrate great potential in decoupling adsorption energies, improving long-term stability, and optimizing reaction kinetics. Existing methods for preparing carbon-based TACs primarily rely on pyrolysis, but this process is often accompanied by problems such as poor metal dispersion, insufficient thermal stability, high energy consumption, and environmental pollution. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of the prior art by proposing a carbon-based iodine support material containing a trimetallic atom catalytic center, its preparation method, and its application, which possesses high conductivity, inhibits polyiodide ion dissolution, promotes polyiodide ion conversion, and effectively suppresses the shuttle effect.

[0007] The first objective of this invention is to provide a method for preparing a carbon-based iodine support material containing a trimetallic atom catalytic center, comprising the following steps: Ketjen black was dispersed in a solvent to obtain a dispersion; Cobalt acetate, 1,3,5-triazine-2,4-diamine and 1,1′-carbonylbisimidazole were added to the dispersion, followed by sonication and then heating to react. After the reaction is complete, the reaction solution is naturally cooled to room temperature, then filtered, washed, and dried to obtain the carbon-based iodine support material containing the trimetallic atom catalytic center.

[0008] Furthermore, the mass-to-volume ratio of Ketjen black to solvent is 100-300 mg: 50 ml.

[0009] Furthermore, the ratio of the mass of Ketjenblack, the molar amount of cobalt acetate, the molar amount of 1,3,5-triazine-2,4-diamine, and the molar amount of 1,1′-carbonyldiimidazole is 100-300 mg: 0.3 mmol: 0.6 mmol: 0.3 mmol.

[0010] Furthermore, the solvent is toluene or dimethylformamide.

[0011] Furthermore, the heating temperature for the reaction is 100~160 ℃, and the reaction time is 24~72 h.

[0012] Further, it was washed successively with deionized water and ethanol, and then vacuum dried overnight at 70-80°C.

[0013] The second objective of this invention is to provide a carbon-based iodine support material containing a trimetallic atom catalytic center prepared by the above-described preparation method.

[0014] The third objective of this invention is to provide an application of the carbon-based iodine support material containing a trimetallic atom catalytic center as described above in the positive electrode of a zinc-iodine battery. The carbon-based iodine support material containing a trimetallic atom catalytic center is used as an iodine positive electrode material after loading elemental iodine.

[0015] Furthermore, the iodine cathode material is mixed with a conductive agent and a binder in a certain proportion and coated onto the current collector to obtain a cathode sheet.

[0016] A fourth objective of this invention is to provide a zinc-iodine battery comprising the aforementioned positive electrode, negative zinc electrode, separator, and zinc salt electrolyte.

[0017] The innovation of this invention lies in the successful construction of a carbon-based iodine support material containing a trimetallic center through an addition-elimination reaction self-assembly strategy using triazine-derived amine compounds and 1,1′-carbonyldiimidazole under the synergistic effect of a metal ion template. Through the coordination interaction between the heteroatoms in the triazine ring and carbonyl group and the metal ion, a highly efficient active center with a well-defined structure and clear catalytic sites is constructed. Applying this carbon-based iodine support material containing a trimetallic catalytic center to zinc-iodine batteries aims to achieve a high-conductivity, shuttle-free iodine support material that effectively promotes the conversion of polyiodide ions. By precisely designing the catalytic center, the conversion process of polyiodide ions is optimized, significantly improving the stability and high-rate performance of the carbon-based iodine support material, ultimately achieving a synergistic improvement in the performance of the iodine cathode.

[0018] Beneficial effects: (1) This invention proposes for the first time a solvothermal method for preparing carbon-based iodine support materials containing trimetallic atom catalytic centers. Through the coordination of heteroatoms in the triazine ring and carbonyl group with metal ions, a center with a clear structure, well-defined catalytic sites, and high catalytic activity was successfully constructed.

[0019] (2) The carbon-based iodine support material designed in this invention has efficient catalytic active sites, optimizes the conversion process of polyiodide ions, and significantly improves the stability and high-rate performance of the carbon-based iodine support material, thereby achieving a synergistic improvement in the performance of the iodine cathode.

[0020] (3) This invention provides a simple and efficient synthesis method that can avoid the problems of metal dispersion and thermal stability during pyrolysis, while overcoming the environmental pollution and high energy consumption problems existing in the existing preparation methods. It has significant innovation and broad application prospects. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the preparation method in Example 1; Figure 2 Transmission electron microscopy (TEM) image of the sample prepared in Example 1; Figure 3 This is a transmission electron microscope (TEM) image of the sample prepared in Comparative Example 1; Figure 4 The graph shows the performance data of the iodine cathodes prepared in Example 1 and Comparative Example 1. Detailed Implementation

[0022] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings to further illustrate the technical solutions of the present invention. However, the present invention is not limited to these embodiments.

[0023] The preparation method proposed in this invention (see...) Figure 1 Commercially available Ketjen black was used as the base material and uniformly dispersed in the reaction solution. Under suitable conditions, it was reacted with Co... 2+ The template guides the orderly progression of the addition-elimination reaction. During this process, the conjugated units and the aromatic system of Ketjenblack promote the in-situ assembly of trimetallic catalytic active centers on the Ketjenblack surface through π-π interactions. Simultaneously, these active centers are confined within the microporous structure of Ketjenblack. Ultimately, a carbon-based iodine support material containing trimetallic atom catalytic centers is formed. Subsequently, iodine cathodes can be successfully constructed by loading elemental iodine through the abundant microporous structure of Ketjenblack using a gas-phase method.

[0024] Example 1 Prepare carbon-based iodine support material and iodine cathode containing a trimetallic atom catalytic center (N3O3Co3).

[0025] (1) In a 100 mL round-bottom flask, Ketjen black is dispersed in a specific solvent to obtain a dispersion; (2) Add cobalt acetate, 1,3,5-triazine-2,4-diamine and 1,1′-carbonyldiimidazole to the dispersion obtained in step (1) and dissolve by sonication. Heat the round-bottom flask at a specific temperature for a specific time. (3) After the reaction solution obtained in step (2) is naturally cooled to room temperature, the precipitate is collected by filtration, washed with deionized water and ethanol in sequence, and dried under vacuum at 80°C overnight.

[0026] The specific solvent in step (1) is toluene or dimethylformamide.

[0027] In steps (1) and (2), the mass of Ketjen black, the molar amount of cobalt acetate, the molar amount of 1,3,5-triazine-2,4-diamine, the molar amount of 1,1′-carbonyldiimidazole, and the volume ratio of the specific solvent are 200 mg: 0.3 mmol: 0.6 mmol: 0.3 mmol: 50 ml.

[0028] The reaction temperature in step (2) is 120 °C and the reaction time is 72 h.

[0029] Preparation of iodine cathode: 50 mg of carbon-based iodine carrier material was mixed with PTFE at a mass ratio of 9:1 and pressed onto carbon paper. After drying at 80°C for 12 h, it was heat-treated with 50 mg of I2 powder at 120°C for 12 h to prepare iodine cathode. The loading amount was controlled by adjusting the amount of I2, and the I2 content was determined by the difference in electrode mass before and after loading.

[0030] Comparative Example 1 Carbon-based iodine support material and iodine cathode containing a trimetallic atom catalytic center (N3S3Co3) were prepared.

[0031] (1) In a 100 mL round-bottom flask, Ketjen black is dispersed in a specific solvent to obtain a dispersion; (2) Add cobalt acetate, 1,3,5-triazine-2,4-diamine and thiocarbonyl diimidazole to the dispersion obtained in step (1) and dissolve by sonication. Heat the round-bottom flask at a specific temperature for a specific time. (3) After the reaction solution obtained in step (2) is naturally cooled to room temperature, the precipitate is collected by filtration, washed with deionized water and ethanol in sequence, and dried under vacuum at 80°C overnight.

[0032] The specific solvent in step (1) is toluene or dimethylformamide.

[0033] In steps (1) and (2), the mass of Ketjen black, the molar amount of cobalt acetate, the molar amount of 1,3,5-triazine-2,4-diamine, the molar amount of thiocarbonyl diimidazole, and the volume ratio of the specific solvent are 200 mg: 0.3 mmol: 0.6 mmol: 0.3 mmol: 50 ml.

[0034] The reaction temperature in step (2) is 120 °C and the reaction time is 72 h.

[0035] Preparation of iodine cathode: 50 mg of carbon-based iodine carrier material was mixed with PTFE at a mass ratio of 9:1 and pressed onto carbon paper. After drying at 80°C for 12 h, it was heat-treated with 50 mg of I2 powder at 120°C for 12 h to prepare iodine cathode. The loading amount was controlled by adjusting the amount of I2, and the I2 content was determined by the difference in electrode mass before and after loading.

[0036] Morphological analysis using transmission electron microscopy (TEM) further fully demonstrates the successful construction of the composite material structure in Example 1. For example... Figure 2 As shown in the TEM image, the composite material fully retains the chain-like nanosphere morphology of Ketjenblack, and its surface is uniformly coated with a continuous and dense confined cobalt metal polymer thin layer.

[0037] TEM analysis of the morphology further verified the successful construction of the composite material structure in Comparative Example 1. Figure 2 As shown in the TEM image, the composite material fully retains the typical chain-like nanosphere morphology of Ketjenblack, while its surface is uniformly coated with a continuous and dense cobalt metal polymer confined thin layer.

[0038] Iodine was loaded onto the carbon-based iodine support material containing a trimetallic atom catalytic center, as described in Example 1 and Comparative Example 1, and used as the iodine positive electrode. A zinc-iodine battery was assembled using 2 M ZnSO4 as the electrolyte and a zinc sheet as the negative electrode. The zinc-iodine battery consisted of an iodine positive electrode (10 mm in diameter), a Zn metal negative electrode disc (10 mm in diameter and 100 μm thick), and a glass fiber separator (12 mm in diameter). The areal loading of I2 was controlled at approximately 1.2 mg·cm³. -2 At the same time, about 30 μL of electrolyte is added to ensure that the electrodes are fully wetted and to meet the requirements for stable battery operation.

[0039] Constant current charge-discharge (GCD) testing was conducted at a current density of 0.5 A g. - ¹ The electrochemical performance of the zinc-iodine battery was evaluated in the voltage range of 0.5–1.6 V.

[0040] like Figure 4 As shown in 'a', there is a reduction plateau and an oxidation plateau, located at approximately 1.15 V and 1.27 V, respectively, indicating that I₂ and I₂... - A reversible single-electron transfer reaction occurred between the ions. The overlapping GCD curves further indicate that the electrochemical process is stable.

[0041] like Figure 4 As shown in b, the battery using N3O3Co3 carbon-based iodine support material at 2 A g - It provides up to 160.7 mAh g⁻¹ at a current density of ¹ - The capacity of ¹ is approximately the theoretical capacity of I₂ (approximately 211 mAh g⁻¹). - ¹, I - The capacity was 76.1% of the theoretical value of I0. However, the battery using the N3S3Co3 carbon-based iodine support material prepared in Comparative Example 1 exhibited continuous capacity decay after 50 cycles, ultimately achieving only 110.5 mAh g⁻¹. - The results above indicate that the introduction of heteroatoms into different monomers can effectively regulate the electronic structure of active sites, thereby significantly affecting the catalytic performance of the support material and playing a crucial role in the overall electrochemical performance of zinc-iodine batteries.

[0042] For any points not covered above, existing technologies shall apply.

[0043] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the direction of the invention or exceeding the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a carbon-based iodine support material containing a trimetallic atom catalytic center, characterized in that, Includes the following steps: Ketjen black was dispersed in a solvent to obtain a dispersion; Cobalt acetate, 1,3,5-triazine-2,4-diamine and 1,1′-carbonylbisimidazole were added to the dispersion, followed by sonication and then heating to react. After the reaction is complete, the reaction solution is naturally cooled to room temperature, then filtered, washed, and dried to obtain the carbon-based iodine support material containing the trimetallic atom catalytic center.

2. The preparation method according to claim 1, characterized in that, The mass-to-volume ratio of Ketjen black to solvent is 100-300 mg: 50 ml.

3. The preparation method according to claim 1, characterized in that, The ratio of the mass of Ketjenblack, the molar amount of cobalt acetate, the molar amount of 1,3,5-triazine-2,4-diamine, and the molar amount of 1,1′-carbonyldiimidazole was 100-300 mg: 0.3 mmol: 0.6 mmol: 0.3 mmol.

4. The preparation method according to claim 1, characterized in that, The solvent is toluene or dimethylformamide.

5. The preparation method according to claim 1, characterized in that, The heating temperature for the reaction is 100~160 ℃, and the reaction time is 24~72 h.

6. The preparation method according to claim 1, characterized in that, Washed successively with deionized water and ethanol, and vacuum dried overnight at 70-80°C.

7. A carbon-based iodine support material containing a trimetallic atom catalytic center, prepared by the preparation method according to any one of claims 1-6.

8. The application of a carbon-based iodine support material containing a trimetallic atom catalytic center as described in claim 7 in the positive electrode of a zinc-iodine battery, characterized in that, Carbon-based iodine support materials containing trimetallic atom catalytic centers are used as iodine cathode materials after loading elemental iodine.

9. The application as described in claim 8, characterized in that, The iodine cathode material is mixed with a conductive agent and a binder in a certain proportion and coated onto the current collector to obtain a cathode sheet.

10. A zinc-iodine battery, characterized in that, It includes the positive electrode sheet, negative zinc sheet, separator, and zinc salt electrolyte as described in claim 9.

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