A dual active center multi-redox site covalent organic framework material and application thereof

Abstract

This invention discloses a dual-active-center, multi-redox-site covalent organic framework material, which is a compound with the following repeating structural unit: The dual-active-center, multi-redox-site covalent organic framework material of this invention exhibits high thermal stability, and as an organic cathode material, it can form a lithium-ion battery capable of operating at 9.761m... 2 Despite its low surface area of ​​ / g, it still exhibits excellent charge and discharge performance, with good rate performance and long-term cycle stability at low current density.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery technology, specifically, it relates to a covalent organic framework material with dual active centers and multiple redox sites and its applications. Background Technology

[0002] As a highly efficient energy storage device, rechargeable batteries offer advantages such as environmental friendliness, high energy density, and long lifespan, and have been widely used in various portable electronic products and new energy vehicles. Energy storage technology, represented by lithium-ion batteries (LIBs), has experienced rapid development. Based on its advantages of high energy density, small size, and long lifespan, lithium batteries are widely used in production and daily life—from electric vehicles to smartphones and other portable electronic products.

[0003] The development of lithium-ion batteries still faces many challenges, such as poor cycle performance and capacity decay. Currently, most inorganic materials used in traditional commercial LIBs are derived from ores or other non-renewable resources, which will lead to resource shortages in the long term. Therefore, replacing inorganic materials with organic materials is urgently needed. Organic materials are composed of lightweight elements, are readily available in nature, and can be synthesized into a wide variety of materials through chemical reactions. Among them, covalent organic frameworks (COFs) have attracted the attention of researchers due to their designable and stable framework structure, abundant and ordered pore structure, and diverse active sites, leading to extensive research in various fields such as gas separation and adsorption, sensing, semiconductors, catalysis, and energy storage.

[0004] In the field of energy storage, covalent organic frameworks (COFs) have attracted widespread attention due to their tunable structure, high porosity, and excellent chemical stability, and are being used to address a series of challenges in the development of lithium-ion batteries. Robust COFs, combining crystallinity and high porosity, exhibit excellent chemical stability. This inherent stability helps improve the cycle performance of COF-based electrodes, thereby extending battery life and minimizing capacity decay during multiple charge-discharge cycles. Furthermore, the high porosity of COFs, coupled with a high specific surface area, facilitates close contact between the electrode material and the electrolyte, promoting efficient charge transfer and reducing polarization effects. In addition, COFs offer high structural designability; the chemical performance of batteries can be improved by introducing groups with reversible redox activity. Simultaneously, to overcome the low specific capacity of COFs, researchers have proposed adjusting the pore size of the material to weaken the interactions between COF layers and improve the utilization rate of active sites within the COF. Summary of the Invention

[0005] The purpose of this invention is to provide a covalent organic framework material with dual active centers and multiple redox sites.

[0006] Another objective of this invention is to provide an application of the aforementioned dual-active-center, multi-redox-site covalent organic framework material in the preparation of organic battery cathode materials.

[0007] Another object of the present invention is to provide an application of the organic battery cathode material in the preparation of lithium batteries.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] In a first aspect, the present invention provides a covalent organic framework material with two active centers and multiple redox sites, which is a compound with the following repeating structural units:

[0010]

[0011] The preparation method of the dual-active-center, multi-redox-site covalent organic framework material includes the following steps:

[0012]

[0013] 2,3,5,6-tetraaminocyclohexane-2,5-diene-1,4-dione, 2,3,8,9,14,15-hexachlorodiquinoxolino[2,3-a:2',3'-c]phenazine, and sodium carbonate were mixed in a molar ratio of 1–2:1:1–8 (preferably 1.6:1:6). Under sealed conditions, the mixture was repeatedly degassed and purged. Deoxygenated DMF was added, and the mixture was stirred at room temperature for 0.5–2 h (preferably 1 h). Then, it was refluxed at a temperature of 150–180 °C (preferably 160 °C) for 1–48 h (preferably 48 h) to obtain the dual-active-center multi-redox-site covalent organic framework material.

[0014] The preparation method of the 2,3,8,9,14,15-hexachlorodiquinoxalino[2,3-a:2',3'-c]phenazine includes the following steps:

[0015]

[0016] Cyclohexane hexahydrate octahydrate and 4,5-dichloro-1,2-phenylenediamine were mixed in a molar ratio of 1:1 to 5 (preferably 1:3.1) and subjected to rapid freezing and degassing under sealed conditions. A mixed solvent of CH3COOH and EtOH was added in a volume ratio of 1:1 to remove oxygen. The mixture was then refluxed at a temperature of 130 to 160°C (preferably 140°C) for 1 to 48 hours (preferably 24 hours). After post-treatment, the 2,3,8,9,14,15-hexachlorodiquinoxolino[2,3-a:2',3'-c]phenazine, i.e., compound 3, was obtained.

[0017] The post-processing steps are as follows:

[0018] After the reaction was completed, the mixture was filtered and washed with hot acetic acid to obtain a green solid. The solid was heated in 30 wt% HNO3 to 90-110°C (preferably 100°C) and stirred for 1-5 h (preferably 3 h). The resulting yellow-green suspension was cooled and filtered, washed repeatedly with ethanol and deionized water, and dried to obtain a crude product. The crude product was dissolved in a small amount of acetone, and then hexane was added to precipitate the product. The mixture was then filtered and dried to obtain the 2,3,8,9,14,15-hexachlorodiquinoxalino[2,3-a:2',3'-c]phenazine.

[0019] In a second aspect, the present invention provides an application of the aforementioned dual-active-center, multi-redox-site covalent organic framework material in the preparation of organic battery cathode materials.

[0020] The application includes the following steps:

[0021] A covalent organic framework material with dual active centers and multiple redox sites, conductive additives, and binders are mixed in a mass ratio of (3-8):(2-4):1 (preferably 6:3:1). Solvent is added and the mixture is ground and mixed into a homogenate. The homogenate is coated onto a clean aluminum foil, the coated aluminum foil is dried, and sliced ​​to obtain the organic battery cathode material.

[0022] The conductive additive is selected from acetylene black.

[0023] The adhesive is selected from polyvinylidene fluoride (PVDF).

[0024] The solvent is selected from NMP.

[0025] The positive electrode material of the organic battery is a circular electrode sheet with a diameter of 12 mm and a thickness of 0.2 mm.

[0026] A third aspect of the present invention provides an application of the organic battery cathode material in the preparation of lithium batteries.

[0027] The application includes the following steps:

[0028] An organic battery positive electrode material (12*0.2mm) was used as the working electrode, and a lithium metal sheet (15.6*0.45mm) was used as the counter electrode. The electrolyte was a LiPF6 system (referring to a 1mol / L LiPF6 solution, using a 1:1:1 volume ratio EC / DEC / DMC (ethylene carbonate / diethyl carbonate / dimethyl carbonate) mixture as the solvent, with 5wt% fluoroethylene carbonate as an additive). The separator was a 16mm Celgard 2400, and the electrolyte drop volume was 100μL. The electrolyte was stored in a glove box in the following order: positive electrode shell-electrolyte-separator-electrolyte-lithium metal-gasket. - Funnel-shaped shrapnel The negative electrode shell of the -2023 type is assembled in sequence, and finally pressed into sheets. After being taken out of the glove box, the lithium battery is obtained.

[0029] By adopting the above technical solution, the present invention has the following advantages and beneficial effects:

[0030] This invention provides a covalent organic framework material with dual active centers and multiple redox sites. Hexaazanaphthalene (HATN) is an electron-deficient imine-based material with a rigid, planar, and conjugated aromatic structure, containing abundant redox-active C=N groups. 2,3,5,6-Tetraaminocyclohexane-2,5-diene-1,4-dione is an active small molecule with C=O groups. The two are condensed using a solvothermal method to form a covalent organic framework with dual active centers (C=N and C=O) and multiple redox-active sites. The lone pairs of electrons in the N and O atoms of the C=N and C=O atoms can interact with Li... + It plays a certain role and is beneficial to Li + The transport of substances is facilitated by the imino linkage, which breaks the traditional π-π conjugated bond, forming a rigid-flexible framework structure. Due to the hydrogen bond interaction between the imino group and the organic electrolyte solution, the material of this invention exhibits higher chemical stability in the electrolyte solution. The dual-active-center, multi-redox-active-site covalent organic framework material of this invention possesses high thermal stability, enabling lithium-ion batteries composed of organic cathode materials to achieve a thermal stability of 9.761 m... 2 Despite its low surface area of ​​ / g, it still exhibits excellent charge and discharge performance, with good rate performance and long-term cycle stability at low current density.

[0031] This invention solves the technical problems of small molecule organic electrode materials being easily soluble and having poor stability. Attached Figure Description

[0032] Figure 1 For HANT-Cl 1 H NMR spectrum.

[0033] Figure 2 The image shows the XRD pattern of the compound with HT-COFs-2 as the repeating structural unit.

[0034] Figure 3 The infrared spectrum of the compound with HT-COFs-2 as the repeating structural unit is shown.

[0035] Figure 4 Thermogravimetric analysis diagram of the compound with HT-COFs-2 as the repeating structural unit.

[0036] Figure 5XPS C1s plot of the compound with HT-COFs-2 as the repeating structural unit.

[0037] Figure 6 XPS N1s plot of the compound with HT-COFs-2 as the repeating structural unit.

[0038] Figure 7 XPS O1s plot of the compound with HT-COFs-2 as the repeating structural unit.

[0039] Figure 8 The pore size distribution diagrams show the compounds with HT-COFs-2 as the repeating structural unit (left) and HT-COFs-1 as the repeating structural unit (right).

[0040] Figure 9 The attached diagram shows the nitrogen adsorption / desorption of a compound with HT-COFs-2 as the repeating structural unit (left) and a compound with HT-COFs-1 as the repeating structural unit (right).

[0041] Figure 10 This is a schematic diagram of the cyclic voltammetry curves of an electrode prepared with a compound HT-COFs-2 as the repeating structural unit and assembled with metallic lithium to form a lithium-ion battery.

[0042] Figure 11 The image shows a comparison of the third cyclic voltammetry curves of an electrode (green) prepared with compound HT-COFs-2 as the repeating structural unit and an electrode (blue) prepared with compound HT-COFs-1 as the repeating structural unit, assembled with lithium metal into a lithium-ion battery.

[0043] Figure 12 The graphs show the cycle performance of lithium-ion batteries assembled with lithium metal, using an electrode (green) prepared with compound HT-COFs-2 as the repeating structural unit and an electrode (blue) prepared with compound HT-COFs-1 as the repeating structural unit.

[0044] Figure 13 The graphs show the rate performance of lithium-ion batteries assembled with lithium metal, using an electrode (green) prepared with compound HT-COFs-2 as the repeating structural unit and an electrode (blue) prepared with compound HT-COFs-1 as the repeating structural unit. Detailed Implementation

[0045] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0046] In this embodiment of the invention, the electrolyte system consisting of cyclohexanehexaone octhydrate, 4,5-dichloro-1,2-phenylenediamine, 2,3,5,6-tetraaminocyclohexane-2,5-diene-1,4-dione (TABQ), Na2CO3, and LiPF6 can all be commercially available.

[0047] Example 1

[0048]

[0049] Preparation of Compound 3: Cyclohexane hexaone octahydrate (0.5 mmol, 1 eq., 0.084 g) and 4,5-dichloro-1,2-phenylenediamine (1.55 mmol, 3.1 eq., 0.274 g) were placed in a three-necked flask, a reflux condenser was added, and a closed system was formed. The three-necked flask was rapidly frozen and degassed through a three-stage refrigeration pump-thawing cycle. Separately, 100 mL of a mixed solvent of CH3COOH and EtOH (volume ratio 1:1) was deoxygenated and transferred to the three-necked flask. The system was heated under reflux at 140 °C for 24 h. After the reaction was complete, the mixture was filtered, and the mixture was washed with hot acetic acid to obtain a green solid. The obtained solid was heated to 100 °C in 30 wt% HNO3 and stirred for 3 h. The resulting yellow-green suspension was cooled, filtered, washed repeatedly with ethanol and deionized water, and dried to obtain the crude product HATN-Cl, i.e., compound 3. The crude product was dissolved in a small amount of acetone, then hexane was added to precipitate it. After filtration and drying, a brown powder HANT-Cl was obtained (its NMR spectrum (H1N) is shown in [reference needed]). Figure 1 As shown, Figure 1 For HANT-Cl 1 H NMR spectrum. 1 H NMR(500MHz,DMSO-d6)δ7.39(s,6H).

[0050] The preparation method of compounds with HT-COFs-2 as repeating structural units includes the following steps:

[0051]

[0052] 2,3,5,6-Tetraaminocyclohexyl-2,5-diene-1,4-dione (0.8 mmol, 1.6 eq., 0.134 g), 2,3,8,9,14,15-hexachlorodiquinoxolino[2,3-a:2',3'-c]phenazine (i.e., compound 3) (0.5 mmol, 1 eq., 0.296 g), and sodium carbonate (3 mmol, 6 eq., 0.318 g) were placed in a three-necked flask, sealed with a reflux apparatus, and the degassing-nitrogen purging process was repeated three times. 100 mL of deoxygenated DMF solvent was transferred into the flask, stirred at room temperature for 1 h, and then refluxed at 160 °C for 48 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and washed alternately with acetonitrile, acetone, and deionized water. This process was repeated three times. The mixture was then dried to obtain a compound with compound HT-COFs-2 as the repeating structural unit.

[0053] Figure 2 The XRD pattern of the compound with compound HT-COFs-2 as the repeating structural unit is shown in the figure. It can be seen from the figure that compared with 2,3,5,6-tetraaminocyclohexane-2,5-diene-1,4-dione and 2,3,8,9,14,15-hexachlorodiquinoxolino[2,3-a:2',3'-c]phenazine (i.e., compound 3), the crystal structure of the obtained sample has changed significantly and new peaks have been formed. This indicates that the two have condensed to form a new crystalline phase. The peak at 2θ of 27.32° of the polymer compound may be related to the (0,0,1) plane. The broad peak band is attributed to the π-π conjugated stacking structure in COFs, indicating the existence of a multilayer COF structure with interlayer spacing, which is conducive to the diffusion of electrode materials and promotes the reaction kinetics.

[0054] Figure 3 The image shows the infrared spectrum of a compound with HT-COFs-2 as the repeating structural unit. As can be seen from the figure, the infrared curve of this polymer undergoes a significant change. (2238 cm⁻¹) -1 The peak at the C≡N group disappears, followed by a peak at 1625 cm⁻¹. -1 and 1157cm -1 A stretching vibration peak of the C=N group appears at 3000–3500 cm⁻¹. -1 The transformation of the -NH2 spike into a broad peak of the NH stretching vibration within the specified range indicates that the polymer compound was successfully synthesized.

[0055] Figure 4The thermogravimetric analysis (TGA) chromatogram of the compound with HT-COFs-2 as the repeating structural unit is shown. The figure reveals a 1.29% mass loss in the polymer over the temperature range of room temperature to 52°C, attributed to the presence of low-boiling-point solvents and a small amount of adsorbed water. Within the 380–403°C range, a 0.73% mass loss occurs due to the presence of a small amount of oligomers. Upon further temperature increase to 514°C, the structure of HT-COFs-2 is further disrupted, with the aromatic structure undergoing carbonization and decomposition. The TGA results indicate that HT-COFs-2 exhibits good thermal stability at 500°C.

[0056] Figure 5 The XPS C1s plot of the compound with HT-COFs-2 as the repeating structural unit shows strong peaks at 284.71, 283.48, 285.44, 287.68, and 288.88 eV, which belong to C=C, CC, C=N, CN, and C=O, respectively.

[0057] Figure 6 The XPS N1s plot of the compound with HT-COFs-2 as the repeating structural unit shows that the peaks at 398.01, 400.18, and 402.48 eV belong to C=N, NH, and CN, respectively. The formation of NH single bonds further confirms the successful synthesis of this polymer compound.

[0058] Figure 7 The XPS O1s plot of the compound with HT-COFs-2 as the repeating structural unit shows that the C=O peak is located at 530.77 eV, indicating that the polymer compound has an embedded C=O structure.

[0059] Figure 8 The images show the pore size distributions of compounds with HT-COFs-2 as the repeating structural unit (left) and HT-COFs-1 as the repeating structural unit (right). As can be seen from the images, the pore size distributions of the compounds with HT-COFs-2 and HT-COFs-1 as the repeating structural unit are concentrated at 1.42 and 1.40 nm, respectively. The increase in pore size facilitates the permeation of electrolyte solution and can promote reaction kinetics.

[0060] Figure 9 The attached diagram shows the nitrogen adsorption / desorption of a compound with HT-COFs-2 as the repeating structural unit (left) and a compound with HT-COFs-1 as the repeating structural unit (right). The specific surface areas of the compound with HT-COFs-2 as the repeating structural unit and the compound with HT-COFs-1 as the repeating structural unit are 9.761 and 0.891 m², respectively. 2 / g, although the pore sizes of the two are similar, the specific surface area has changed significantly. The compound with HT-COFs-2 as the repeating structural unit has a rich specific surface area which is conducive to the penetration of electrolyte solution and lithium ion diffusion, and can promote the reaction kinetics.

[0061] Comparative Example 1

[0062] A covalent organic framework material with a smaller pore size and similar structure, possessing dual active centers and multiple redox active sites, namely compound HT-COFs-1, has the following structural formula:

[0063]

[0064] The preparation method of compounds with HT-COFs-1 as repeating structural units includes the following steps:

[0065]

[0066] 2,3,5,6-Tetraaminocyclohexane-2,5-diene-1,4-dione (0.8 mmol, 1.6 eq., 0.134 g), 1,4,5,8,9,11-hexaazatribenzanilonitrile (0.5 mmol, 1 eq., 0.192 g), and sodium carbonate (3 mmol, 6 eq., 0.318 g) were placed in a three-necked flask, sealed after adding a reflux apparatus, and the degassing-nitrogen purging process was repeated three times. 100 mL of deoxygenated DMF solvent was transferred into the flask, stirred at room temperature for 1 h, and then refluxed at 160 °C for 48 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and washed alternately with acetonitrile, acetone, and deionized water. This process was repeated three times. The mixture was dried to obtain a compound with HT-COFs-1 as the repeating structural unit.

[0067] Example 2

[0068] Organic cathode materials were prepared from the compounds with HT-COFs-2 as the repeating structural unit or the compounds with HT-COFs-1 as the repeating structural unit, as follows:

[0069] A mixture of 0.3 g of compound with HT-COFs-2 as the repeating structural unit or 0.3 g of compound with HT-COFs-1 as the repeating structural unit, conductive additive acetylene black (0.15 g), and binder polyvinylidene fluoride (PVDF) (0.05 g) in a mass ratio of 6:3:1 was prepared and ground into a homogenate. The homogenate was coated onto a clean aluminum foil (single-sided smooth 16 μm * 100 mm * 70 mm). The coated aluminum foil was placed in a vacuum drying oven at 90 °C and dried for 24 h. The resulting film thickness was approximately 0.2 mm. The dried aluminum foil was punched into circular electrode sheets with a diameter of 12 mm using an MSK-T10 slicing machine and stored in a MIKROUNA glove box for later use.

[0070] The above cathode material is used to prepare a lithium battery, and the assembly steps are as follows:

[0071] The above-mentioned circular electrode (12*0.2mm) was used as the working electrode, and the lithium metal sheet (15.6*0.45mm) was used as the counter electrode. The electrolyte was a LiPF6 system (this system refers to a 1mol / L LiPF6 solution, using a 1:1:1 volume ratio EC / DEC / DMC (ethylene carbonate / diethyl carbonate / dimethyl carbonate) mixture as the solvent, and adding 5wt% fluoroethylene carbonate as an additive). The separator was a 16mm Celgard 2400, and the electrolyte drop volume was 100μL. The electrolyte was stored in a glove box in the following order: positive electrode shell - electrode - electrolyte - separator - electrolyte - lithium metal - gasket. - Funnel-shaped shrapnel The negative electrode shell of the -2023 type is assembled in sequence, and finally pressed into sheets. After being taken out of the glove box, the lithium battery is obtained.

[0072] The specific method for testing the electrochemical reaction process of the above lithium battery is as follows:

[0073] The prepared lithium battery was clamped at the corresponding positive and negative terminals using a battery test clip, and the cyclic voltammetry curves of the battery were tested using an electrochemical workstation at a scan rate of 0.1 mV / s within the range of 1.2–3.9 V. The cyclic voltammetry curves show that the redox reactions of C=O and C=N in the compound with HT-COFs-2 as the repeating structural unit are a reversible process, and the charge-discharge process of the electrode material is also reversible.

[0074] The cycle performance of the above lithium battery was tested using the following method:

[0075] The prepared lithium battery was clamped at the corresponding positive and negative terminals using a battery test clip, and the cycle performance curve of the battery at a current density of 0.1 A / g was measured using the Xinwei test system.

[0076] Figure 10This is a schematic diagram of the cyclic voltammetry curves of an electrode prepared with compound HT-COFs-2 as the repeating structural unit and lithium metal assembled into a lithium-ion battery. During the initial scan, three reduction peaks at 1.69V, 2.05V, and 2.39V can be clearly observed, with the corresponding oxidation peak at 3.20V. Furthermore, the curves of the second and third cycles basically overlap, indicating that the electrode reaction process of the electrode prepared with compound HT-COFs-2 as the repeating structural unit is reversible.

[0077] Figure 11 The image shows a comparison of the third cyclic voltammetry (CV) curves of an electrode (green) prepared with compound HT-COFs-2 as the repeating structural unit and an electrode (blue) prepared with compound HT-COFs-1 as the repeating structural unit, assembled with lithium metal into a lithium-ion battery. Compared with the compound with compound HT-COFs-1 as the repeating structural unit, the compound with compound HT-COFs-2 as the repeating structural unit has a larger CV curve area and a higher redox peak formed by the chemical reaction, indicating that the compound with compound HT-COFs-2 as the repeating structural unit has a higher utilization rate of active sites.

[0078] Figure 12 The graphs show the cycle performance of lithium-ion batteries assembled with lithium metal, using an electrode (green) prepared with compound HT-COFs-2 as the repeating structural unit and an electrode (blue) prepared with compound HT-COFs-1 as the repeating structural unit. The graphs show that, compared to the initial capacity of 76.35 mAh / g for the electrode prepared with compound HT-COFs-1 as the repeating structural unit, the electrode prepared with compound HT-COFs-2 as the repeating structural unit achieves an initial charge specific capacity of 188.95 mAh / g, and a capacity of 82.51 mAh / g after 300 cycles. This indicates that the cathode prepared with compound HT-COFs-2 as the repeating structural unit exhibits good stability and cycle performance.

[0079] The specific method for testing the rate performance of the above-mentioned lithium battery is as follows:

[0080] The prepared lithium battery was clamped at the corresponding positive and negative terminals using a battery test clip, and the rate performance curve of the battery under different current densities was measured using the Xinwei test system.

[0081] Figure 13The graphs show the rate performance of lithium-ion batteries assembled with lithium metal, using compounds with HT-COFs-2 as the repeating structural unit (green) and HT-COFs-1 as the repeating structural unit (blue). The graphs show that the electrode with HT-COFs-2 as the repeating structural unit exhibits superior rate performance compared to the electrode with HT-COFs-1 at different current densities. Furthermore, when the current density is restored to 0.1 A / g, the charging capacity still recovers to 93.97 mAh / g, indicating that the cathode prepared with HT-COFs-2 as the repeating structural unit possesses excellent rate performance and stability.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A covalent organic framework material with dual active centers and multiple redox sites, characterized in that, Compounds whose repeating structural units are:

2. The dual-active-center, multi-redox-site covalent organic framework material according to claim 1, characterized in that, The preparation method of the dual-active-center, multi-redox-site covalent organic framework material includes the following steps: 2,3,5,6-tetraaminocyclohexane-2,5-diene-1,4-dione, 2,3,8,9,14,15-hexachlorodiquinoxolino[2,3-a:2',3'-c]phenazine, and sodium carbonate were mixed in a molar ratio of 1–2:1:1–8. Under sealed conditions, the mixture was repeatedly degassed and purged. Deoxygenated DMF was then added, and the mixture was stirred at room temperature for 0.5–2 h, followed by reflux at 150–180 °C for 1–48 h to obtain the dual-active-center, multi-redox-site covalent organic framework material.

3. The dual-active-center, multi-redox-site covalent organic framework material according to claim 2, characterized in that, The preparation method of the 2,3,8,9,14,15-hexachlorodiquinoxalino[2,3-a:2',3'-c]phenazine includes the following steps: Cyclohexane hexaone octahydrate and 4,5-dichloro-1,2-phenylenediamine were mixed in a molar ratio of 1:1 to 5 and subjected to rapid freezing and degassing under sealed conditions. A mixed solvent of CH3COOH and EtOH (volume ratio of CH3COOH to EtOH 1:1) was added to remove oxygen. The mixture was then refluxed at 130–160 °C for 1–48 h. After post-treatment, the 2,3,8,9,14,15-hexachlorodiquinoxalino[2,3-a:2',3'-c]phenazine, compound 3, was obtained.

4. The dual-active-center, multi-redox-site covalent organic framework material according to claim 3, characterized in that, The post-processing steps are as follows: After the reaction was completed, the mixture was filtered and washed with hot acetic acid to obtain a green solid. The solid was heated in 30 wt% HNO3 to 90-110 °C and stirred for 1-5 h. The resulting yellow-green suspension was cooled, filtered, washed repeatedly with ethanol and deionized water, and dried to obtain a crude product. The crude product was dissolved in a small amount of acetone, and then hexane was added to precipitate the product. The mixture was then filtered and dried to obtain the 2,3,8,9,14,15-hexachlorodiquinoxalino[2,3-a:2',3'-c]phenazine.

5. The application of a dual-active-center, multi-redox-site covalent organic framework material as described in any one of claims 1 to 3 in the preparation of cathode materials for organic batteries.

6. The application according to claim 5, characterized in that, The application includes the following steps: A covalent organic framework material with dual active centers and multiple redox sites in a mass ratio of (3-8):(2-4):1, conductive additives, and binders are mixed, and a solvent is added to grind and mix the mixture into a homogenate. The homogenate is then coated onto a clean aluminum foil, and the coated aluminum foil is dried and sliced ​​to obtain the organic battery cathode material.

7. The application according to claim 6, characterized in that, The conductive additive is selected from acetylene black; The adhesive is selected from polyvinylidene fluoride.

8. The application according to claim 6, characterized in that, The solvent is selected from N-methylpyrrolidone; The positive electrode material of the organic battery is a circular electrode sheet with a diameter of 12 mm and a thickness of 0.2 mm.

9. The application of the organic battery cathode material according to any one of claims 5 to 8 in the preparation of lithium batteries.

10. The application according to claim 9, characterized in that, The application includes the following steps: Organic battery positive electrode material was used as the working electrode, lithium metal sheet as the counter electrode, LiPF6 electrolyte was used, 16mm Celgard 2400 separator was used, and the electrolyte drop volume was 100μL. The cells were assembled in a glove box in the following order: 2023 type positive electrode shell - electrode sheet - electrolyte - separator - electrolyte - lithium metal - gasket - funnel-shaped spring sheet - 2023 type negative electrode shell. Finally, the cells were pressed and removed from the glove box to obtain the lithium battery.

Images