A class of covalent organic polymer materials based on polyquinone imidazole, their preparation methods, and their applications in lithium-ion battery anode materials.

Abstract

This invention belongs to the field of lithium-ion battery technology, and discloses a class of polyquinone-imidazole covalent organic polymer materials, their preparation methods, and their applications in lithium-ion battery anode materials. This invention prepares two polyquinone-imidazole organic polymer materials, denoted as HATTABQ and HATTAPT, through a hydrothermal synthesis reaction of hexaazanaphthalic acid (HAT-6COOH) and tetraamino-p-benzodiquinone (TABQ) or 2,3,7,8-tetraamino-1,4,6,9-tetraquinonephenolazine (TAPT). Lithium-ion batteries based on these materials exhibit high specific capacity and good cycle stability. At a current density of 10 A / g, the HATTABQ electrode achieves a discharge specific capacity of 279.2 mAh / g in the first cycle and can stably cycle for 20,000 cycles with a capacity retention of 78.4%. At a current density of 5 A / g, the HATTAPT electrode achieves a discharge specific capacity of 473.8 mAh / g in the first cycle and can stably cycle for 2,000 cycles with a capacity retention of 64.3%. The preparation method of this invention is simple and conducive to large-scale industrial production, and has potential application value in lithium-ion battery anode materials.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery anode material preparation technology, specifically involving a class of covalent organic polymer materials (HATTABQ or HATTAPT) based on polyquinone imidazole, their preparation methods, and their application in lithium-ion battery anode materials. Background Technology

[0002] With the strong government support for the electric vehicle industry in recent years, and the rapid development of smartphones and energy storage grid systems, the demand for clean and efficient energy storage technologies is increasing. Lithium-ion batteries (LIBs) have been the preferred choice for energy storage devices due to their advantages such as small size, long cycle life, high power density, and low self-discharge rate, dominating the market for rechargeable batteries in mobile electronic devices and electric vehicles.

[0003] In lithium-ion battery research, besides factors such as cathode materials and electrolytes, anode materials also largely determine the overall performance of the battery. To promote the industrialization and practical application of high-performance lithium-ion batteries, researchers have devoted considerable effort to the study of anode materials. Currently, carbon-based materials, silicon-based materials, tin-based materials, transition metal oxides, and sulfides are mainly used as anode materials for lithium-ion batteries. Among them, commercially available graphite has a theoretical capacity of only 372 mAh g⁻¹. -1 Lithium-modified graphite also presents safety concerns. In contrast, organic polymer electrode materials have attracted increasing attention due to their high theoretical specific capacity, high safety, environmental friendliness, low cost, and flexible design, and are considered candidate materials for next-generation green electrode materials in lithium-ion batteries. However, achieving long-term cycle stability and capacity retention at high current densities remains a significant challenge due to the weak structural stability and low conductivity of organic polymers.

[0004] Covalent organic frameworks (COFs) are a class of novel crystalline organic porous polymers with high specific surface area, long-range ordered structure, and customizable functionalization, which are significantly different from traditional polymers. The uniform pore structure and surface and near-surface redox active sites in the network structure of COFs are beneficial for enhancing Li... +While COFs exhibit good transport kinetics, their active sites are deeply buried due to the high-density stacked two-dimensional layered structure, resulting in insufficient utilization of some redox active sites and a decrease in reversible specific capacity. Furthermore, COFs are typically composed of reversible covalent bonds (C=N, usually formed by the combination of aldehyde and amino groups), which are prone to breakage under extreme conditions, leading to poor chemical stability and limiting their application in lithium-ion batteries. In contrast, covalent organic polymers (COPs) are another type of porous organic polymer formed by irreversible strong covalent bonds, exhibiting excellent chemical stability and existing in semi-crystalline or amorphous forms, allowing them to remain stable even in harsh chemical environments. The quinone-imidazolium repeating units of the two COP materials involved in this invention are formed by the combination of carboxyl and amino groups, which is more stable than the C=N combination of aldehyde and amino groups. Simultaneously, thanks to this amorphous structure, the active sites of the polyquinone-imidazolium covalent organic polymers involved in this invention are effectively exposed to the electrochemical environment, exhibiting a high specific capacity. Therefore, rationally designing novel and highly stable organic electrode materials for use in LIBs anode materials to solve these problems is crucial for improving the performance of LIBs. Summary of the Invention

[0005] This invention relates to a class of polyquinone-imidazole covalent organic materials with high lithium storage capacity, their preparation methods, and their application in lithium-ion batteries. The purpose is to provide a covalent organic material with high energy storage and cycle stability.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A class of covalent organic polymer materials based on polyquinone imidazole, including HATTABQ and HATTAPT, the structural formulas of which are shown in (I) and (II), respectively:

[0008]

[0009] Furthermore, the preparation method of the above-mentioned covalent organic polymer material based on polyquinone imidazole, namely HATTABQ, includes the following steps: dispersing compound 1 and compound 2 in ultrapure water, adding a catalyst, placing them in a reaction vessel, reacting at 180°C for 3 days, and then filtering, washing, and drying to obtain the black product HATTABQ;

[0010] The preparation method of HATTAPT includes the following steps: dispersing compound 1 and compound 3 in ultrapure water, adding a catalyst, placing the mixture in a reaction vessel, reacting at 180°C for 3 days, and then filtering, washing, and drying to obtain the black product HATTAPT.

[0011] Compound 1 is hexaazanaphthylcarboxylic acid, compound 2 is tetraamino-p-benzodiquinone, and compound 3 is 2,3,7,8-tetraamino-1,4,6,9-tetraquinone phenolazine.

[0012] Furthermore, in the aforementioned class of covalent organic polymer materials based on polyquinone imidazole, the structural formulas of compounds 1, 2, and 3 are shown as (III), (IV), and (V), respectively:

[0013]

[0014] Furthermore, in the aforementioned type of covalent organic polymer material based on polyquinone imidazole, the catalyst is a 3M acetic acid solution.

[0015] Furthermore, in the aforementioned covalent organic polymer material based on polyquinone imidazole, the molar ratio of compound 1 to compound 2 and compound 1 to compound 3 is 1:1.5.

[0016] Furthermore, in the aforementioned type of covalent organic polymer material based on polyquinone imidazole, the drying conditions are 60°C for 12 hours.

[0017] The above-mentioned type of covalent organic polymer material based on polyquinone imidazole is used as a negative electrode material in lithium-ion batteries.

[0018] Furthermore, the above applications are implemented as follows:

[0019] 1) The covalent organic polymer material based on polyquinone imidazole as described in claim 1 is mixed with conductive agent Super P and binder CMC, and H2O solvent is added to grind it into a uniform and particle-free slurry. The slurry is then uniformly coated onto the current collector using a tetrahedral mold.

[0020] 2) Place the coated current collector in a 60℃ vacuum drying oven and dry for 12 hours to remove residual solvent. Then cut it into circles with a diameter of 12mm using a cutting machine to obtain the electrode sheet.

[0021] 3) In an argon-protected glove box, keep the water and oxygen levels in the glove box below 0.1 ppm. Using the 2032 coin cell standard, place the electrode sheet obtained in step 2), PP separator, electrolyte, 16 mm diameter lithium metal sheet, gasket, spring sheet, and positive electrode shell in the negative electrode shell in sequence.

[0022] 4) Seal the battery with a packaging machine to obtain a 2032 type button lithium-ion battery.

[0023] Furthermore, in the above application method, in step 1), by mass ratio, a type of covalent organic polymer material based on polyquinone imidazole: Super P:CMC is 6:3:1, and the current collector is copper foil.

[0024] Furthermore, in the above application method, step 3), the electrolyte is prepared by dissolving LiPF6 in a mixture of EC and DEC, so that the concentration of LiPF6 is 1M and the volume ratio of EC to DEC is 1:1.

[0025] The beneficial effects of this invention are:

[0026] 1. The HATTABQ and HATTAPT synthesized in this invention exhibit high capacity and good stability as negative electrode materials for lithium-ion batteries. At a current density of 10 A / g, the HATTABQ electrode achieves a discharge specific capacity of 279.2 mAh / g in the first cycle and can be stably cycled for 20,000 cycles with a capacity retention of 78.4%. At a current density of 5 A / g, the HATTAPT electrode achieves a discharge specific capacity of 473.8 mAh / g in the first cycle and can be stably cycled for 2,000 cycles with a capacity retention of 64.3%.

[0027] 2. The HATTABQ and HATTAPT synthesized in this invention are compatible with currently commercially available electrolytes and have good compatibility, eliminating the need to develop new electrolytes.

[0028] 3. The HATTABQ and HATTAPT materials of the present invention are easy to synthesize, use water as a solvent, and are green, simple and efficient. Attached Figure Description

[0029] Figure 1 These are the FTIR plots of HATTABQ(a) and HATTAPT(b).

[0030] Figure 2 These are the XRD patterns of HATTABQ(a) and HATTAPT(b).

[0031] Figure 3 The figures show the cyclic voltammetry curves of HATTABQ(a) and HATTAPT(b) as lithium-ion battery anode materials at different scan rates.

[0032] Figure 4 (a) is a long-cycle graph of HATTABQ as a negative electrode material for lithium-ion batteries at a current density of 10 A / g. Figure 4 (b) is a long-cycle diagram of HATTAPT as a negative electrode material for lithium-ion batteries at a current density of 5 A / g.

[0033] Figure 5(a) is a rate capability diagram of HATTABQ as a negative electrode material for lithium-ion batteries. Figure 5 (b) is a rate capability diagram of HATTAPT as a negative electrode material for lithium-ion batteries. Detailed Implementation

[0034] Experimental Example 1: Preparation of HATTABQ

[0035] Compound 1, hexaazanaphthalic acid (HAT-6COOH) (99.66 mg, 0.2 mmol), and compound 2, tetraaminobenzodiquinone (TABQ) (50.44 mg, 0.3 mmol), were ground and mixed evenly, then dispersed in 30 mL of ultrapure water. 1 mL of 3 M acetic acid solution was added dropwise as a catalyst. After ultrasonic dispersion for 15 min, the mixture was transferred to a 50 mL polytetrafluoroethylene-lined container and placed in a reaction vessel. The reaction was carried out at 180 °C for 3 days. After cooling to room temperature, the product was filtered through a sintered glass filter and washed three times with 20 mL of ultrapure water and 20 mL of DMSO, respectively. The resulting black product, HAT-6COOH, was then dried in a vacuum drying oven at 60 °C for 12 h. The specific synthetic route is as follows:

[0036]

[0037] Example 2: Preparation of HATTAPT

[0038] Compound 1, hexaazanaphthalic acid (HAT-6COOH) (99.66 mg, 0.2 mmol), and compound 3, 2,3,7,8-tetraamino-1,4,6,9-tetraquinone phenolazine (TAPT) (90.07 mg, 0.3 mmol), were ground and mixed thoroughly, then dispersed in 30 mL of ultrapure water. 1 mL of 3 M acetic acid solution was added dropwise as a catalyst. After ultrasonic dispersion for 15 min, the mixture was transferred to a 50 mL polytetrafluoroethylene-lined container and placed in a reaction vessel. The reaction was carried out at 180 °C for 3 days. After cooling to room temperature, the product was filtered through a sintered glass filter and washed three times with 20 mL of ultrapure water and 20 mL of DMSO, respectively. The resulting black product, HATTAPT, was then dried in a vacuum drying oven at 60 °C for 12 h. The specific synthetic route is as follows:

[0039]

[0040] The obtained materials were characterized by FTIR, and the results are as follows: Figure 1 (a) and Figure 1 As shown in (b). Figure 1 (a) It can be seen that the infrared characteristic peak is at 3324 cm⁻¹. -1 And 3395cm -1 At 1750 cm⁻¹, the stretching vibration of -NH₂, belonging to monomer TABQ, is observed. -1At this point, the stretching vibration of C=O(-COOH) belonging to the monomer HAT-6COOH can be observed at 3324 cm⁻¹. -1 And 3395cm -1 The -NH2 infrared characteristic peak at 1750 cm⁻¹ and 1750 cm⁻¹ -1 The disappearance of the characteristic peak of C=O(-COOH) at this point indicates that the -NH2 of monomer TABQ and the -COOH of HAT-6COOH have successfully combined. Furthermore, the FTIR curve of product HATTABQ shows that at 1710 cm⁻¹... -1 The corresponding C=O characteristic peak is at 1631 cm⁻¹. -1 The corresponding stretching vibrations at C=C and C=N occur at 1485cm. -1 The characteristic peak at 1291 cm⁻¹ is attributed to the C=N stretching vibration of imidazole. -1 The corresponding CN stretching vibration indicates that HATTABQ has been successfully synthesized. Similarly, it can be seen that... Figure 1 In (b), the infrared characteristic peak is at 3312 cm⁻¹. -1 And 3373cm -1 At 1750 cm⁻¹, the stretching vibration of -NH₂, belonging to monomeric TAPT, is observed. -1 At this point, the stretching vibration is attributed to the C=O(-COOH) group of the monomer HAT-6COOH. Simultaneously, the FTIR curve of the product HATTAPT shows that at 1712 cm⁻¹... -1 The corresponding C=O characteristic peak is at 1600 cm⁻¹. -1 The corresponding characteristic peaks for C=C and C=N are at 1480 cm⁻¹. -1 The characteristic peak at 1282 cm⁻¹ is attributed to the C=N stretching vibration of imidazole. -1 The corresponding CN stretching vibration indicates that HATTAPT has been successfully synthesized. The obtained material was characterized by XRD, and the results are as follows: Figure 2 (a) and Figure 2 As shown in (b). Figure 2 (a) It can be seen that HATTABQ exhibits a broad peak at 27.34°(002), corresponding to a crystal plane spacing of This interplanar spacing is similar to the typical distance for π-π stacking (usually between 3.3 and 1.5). The correlation between the two peaks (002 and 002) indicates a stable π-π stacking structure between the HATTABQ layers. Furthermore, the intensity of the peak on the (002) crystal plane is proportional to the degree of graphitization, suggesting that HATTABQ possesses a graphitized structure. Similarly, it can be concluded that... Figure 2 (b) indicates that HATTAPT exhibits a broad peak at 28.1°(002), corresponding to a crystal plane spacing of This indicates the existence of stable π-π stacking and graphitization structures between the HATTAPT layers. These stable π-π stacking and graphitization structures facilitate the full exposure of active sites, thus making the actual specific capacity of the material closer to its theoretical specific capacity.

[0041] Example 3: Preparation of negative electrode sheet

[0042] HATTABQ or HATTAPT, Super P, and CMC are ground together with H2O in a mass ratio of 6:3:1 to form a uniform, particle-free slurry. The slurry is then evenly coated onto the current collector copper foil using a tetrahedral mold. The coated copper foil is then placed in a vacuum drying oven at 60°C and dried for 12 hours to remove residual solvent. The copper foil is then cut into circular copper sheets with a diameter of 12 mm using a cutting machine to obtain the negative electrode sheet.

[0043] Experiment Example 4: Assembling a Battery

[0044] Using the 2032 coin cell standard, the battery was assembled in an argon-protected glove box, specifically ensuring that the water and oxygen levels in the glove box were both less than 0.1 ppm. The negative electrode sheet prepared in Example 3, a PP separator, 40 μL of electrolyte (1 M LiPF6 dissolved in a 1:1 volume ratio mixture of EC and DEC), a 16 mm diameter circular lithium sheet, a gasket, a spring, and the positive electrode shell were sequentially placed in the negative electrode shell. The shell was then sealed using a packaging machine to obtain a 2032 lithium-ion coin cell. Cyclic voltammetry and electrochemical impedance spectroscopy were then performed using a Bio-Logic electrochemical workstation, followed by constant current charge-discharge testing using a LANHE battery testing system.

[0045] After the assembled lithium-ion batteries were left to stand at room temperature for 2 hours, cyclic voltammetry, rate testing, and long-cycle testing were performed within a voltage window of 0.01-3V. Figure 3 As shown in (a) and 3(b), these correspond to the cyclic voltammetry test curves of HATTAPT and HATTABQ for lithium-ion battery anode materials at scan rates of 0.2 mV / s–1 mV / s, respectively. With the continuous increase of the scan rate, the current density also continuously increases. Figure 3 (a) It can be seen that for HATTABQ, there is only one pair of redox peaks. When the scan rate is 0.2 mV / s, the oxidation peak is located at 0.8 V (vs. Li / Li). + The reduction peak is located at 0.4V (vs. Li / Li). + );Depend on Figure 3 (b) It can be seen that for HATTAPT, there are two pairs of redox peaks. When the scan rate is 0.2 mV / s, the oxidation peak is located at 0.9 / 1.6 V (vs. Li / Li). + The reduction peak is located at 0.7 / 1.5V (vs. Li / Li).+ ).

[0046] like Figure 4 As shown in (a) and 4(b), the HATTABQ electrode was tested for cycle stability at a current density of 10 A / g, and the HATTAPT electrode was tested at a current density of 5 A / g. At 10 A / g, the HATTABQ electrode achieved a discharge specific capacity of 279.2 mAh / g in the first cycle and remained stable for 20,000 cycles with a capacity retention of 78.4%. The first-cycle coulombic efficiency was low at only 50.04%, which may be due to the formation of an irreversible SEI film or other side reactions. At 5 A / g, the HATTAPT electrode achieved a discharge specific capacity of 473.8 mAh / g in the first cycle and remained stable for 2,000 cycles with a capacity retention of 64.3%. The first-cycle coulombic efficiency was also low at only 52.72%.

[0047] like Figure 5 As shown in (a) and 5(b), rate tests were conducted on the HATTABQ and HATTAPT electrodes at different current densities. At a current density of 1 A / g, the HATTABQ and HATTAPT electrodes exhibited first-cycle discharge specific capacities as high as 879.5 mAh / g and 935.5 mAh / g, respectively, but their first-cycle coulombic efficiencies were both below 60%. At a current density of 10 A / g, the HATTABQ electrode achieved a specific capacity of 260 mAh / g, and when the current density returned to 1 A / g, the capacity almost returned to the initial stable specific capacity of 500 mAh / g. At a current density of 5 A / g, the HATTAPT electrode achieved a specific capacity of 330 mAh / g, and when the current returned to 1 A / g, the specific capacity almost returned to the initial stable specific capacity of 490 mAh / g.

Claims

1. A class of covalent organic polymer materials based on polyquinone imidazole, characterized in that, The aforementioned covalent organic polymer material based on polyquinone zimidazole is HATTABQ or HATTAPT, and the structural formulas of HATTABQ and HATTAPT are shown in (I) and (II), respectively: 。 2. The covalent organic polymer material based on polyquinone zimidazole according to claim 1, characterized in that, The preparation method of HATTABQ includes the following steps: dispersing compound 1 and compound 2 in ultrapure water, adding a catalyst, placing the mixture in a reaction vessel, reacting at 180 °C for 3 days, and then filtering, washing, and drying to obtain the black product HATTABQ; The preparation method of HATTAPT includes the following steps: dispersing compound 1 and compound 3 in ultrapure water, adding a catalyst, placing the mixture in a reaction vessel, reacting at 180 °C for 3 days, and then filtering, washing, and drying to obtain the black product HATTAPT; The structural formulas of compounds 1, 2, and 3 are shown in (III), (IV), and (V), respectively: 。 3. The covalent organic polymer material based on polyquinone zimidazole according to claim 2, characterized in that, The catalyst is a 3 M acetic acid solution.

4. The covalent organic polymer material based on polyquinone zimidazole according to claim 2, characterized in that, The molar ratio of compound 1 to compound 2 and compound 1 to compound 3 is 1:1.

5.

5. A type of covalent organic polymer material based on polyquinone zimidazole according to claim 2, characterized in that, The drying conditions were 60 °C for 12 h.

6. The application of the covalent organic polymer material based on polyquinone imidazole as described in claim 1 as a negative electrode material in lithium-ion batteries.

7. The application according to claim 6, characterized in that, The method is as follows: 1) The covalent organic polymer material based on polyquinone imidazole as described in claim 1 is mixed with conductive agent Super P and binder CMC, and H2O solvent is added to grind it into a uniform and particle-free slurry. The slurry is then uniformly coated onto the current collector using a tetrahedral mold. 2) Place the coated current collector in a 60 °C vacuum drying oven and dry for 12 h to remove residual solvent. Then cut it into circles with a diameter of 12 mm using a cutting machine to obtain the electrode sheet. 3) In an argon-protected glove box, keep the water and oxygen levels in the glove box below 0.1 ppm. Using the 2032 coin cell standard, place the electrode sheet obtained in step 2), PP separator, electrolyte, 16 mm diameter lithium metal sheet, gasket, spring sheet, and positive electrode shell in the negative electrode shell in sequence. 4) Seal the battery with a packaging machine to obtain a 2032 type button lithium-ion battery.

8. The application according to claim 7, characterized in that, In step 1), by mass ratio, a type of covalent organic polymer material based on polyquinone imidazole: Super P:CMC is 6:3:1, and the current collector is copper foil.

9. The application according to claim 7, characterized in that, In step 3), the electrolyte is prepared by dissolving LiPF6 in a mixture of EC and DEC to make the concentration of LiPF6 1 M and the volume ratio of EC to DEC 1:1.

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