An organic polymer electrode material, a preparation method therefor, and an application thereof
By preparing organic polymer electrode materials containing tripyrazine structural units, the problems of low specific capacity and easy solubility of lithium-ion battery cathode materials have been solved, enabling the application of lithium-ion batteries with high specific capacity and good cycle performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUN YAT SEN UNIV
- Filing Date
- 2024-08-19
- Publication Date
- 2026-06-02
AI Technical Summary
Existing lithium-ion battery cathode materials suffer from problems such as low specific capacity, high cost, scarce resources, toxicity, and easy solubility in organic electrolytes, which limit their application and development.
Organic polymer electrode materials containing tripyrazine structural units were used to prepare organic polymer electrode materials with high conductivity and multiple redox active sites by connecting groups with conjugated carbonyl groups.
It achieves high specific capacity, good rate performance and cycle performance, and solves the problems of low capacity and easy solubility of existing materials, making it suitable for high energy density lithium-ion batteries.
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Figure CN118930853B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of battery materials technology, specifically relating to an organic polymer electrode material, its preparation method, and its application. Background Technology
[0002] Lithium-ion batteries are high-energy rechargeable batteries with advantages such as high energy density, high operating voltage, long cycle life, and wide operating temperature range, and are widely used in portable electronic devices, electric vehicles, smart grids, and other fields. The cathode material, as one of the important components of a lithium-ion battery, plays a decisive role in its energy density and cost. Currently, commercially available lithium-ion battery cathode materials are mainly traditional lithium transition metal oxides and phosphates, such as LiCoO2, LiMn2O4, and LiFePO4. However, compared to graphite anodes (with a theoretical specific capacity of 372 mAh·g),... -1 Compared to traditional inorganic cathode materials, these materials typically have lower theoretical specific capacities, which is considered the most significant bottleneck for the further development of lithium-ion batteries. Furthermore, these traditional inorganic cathode materials containing transition metal elements (Co, Ni, Mn, etc.) generally suffer from high prices, resource scarcity, toxicity, poor recyclability, and environmental unfriendliness. In the long run, humanity may face a resource crisis. Therefore, to alleviate the increasingly severe energy depletion problem and meet the demand for higher energy density, the development of new cathode materials with higher specific capacity, lower cost, and non-toxicity is urgently needed.
[0003] Compared to inorganic materials, organic materials are composed of naturally abundant elements such as C, H, N, O, and S. They are readily available, low-cost, environmentally friendly, and possess flexible molecular designability and multiple redox active centers. They typically exhibit high theoretical specific capacity, making them excellent candidates for low-cost and sustainable lithium-ion battery electrode materials. Currently, organic electrode materials, including carbonyl compounds, conductive polymers, organosulfur compounds, and organic free radicals, are widely used in lithium-ion batteries. However, organic electrode materials often suffer from problems such as easy solubility in organic electrolytes and inherently poor conductivity, resulting in lower actual capacity and poor cycle performance, significantly limiting their practical applications. Therefore, designing and developing organic cathode materials with high conductivity, good rate performance and cycle performance, and insolubility in organic electrolytes is of great significance. Summary of the Invention
[0004] To overcome the problems existing in the prior art, one objective of this invention is to provide an organic polymer electrode material. A second objective is to provide a method for preparing the aforementioned organic polymer electrode material. A third objective is to provide applications of the aforementioned organic polymer electrode material. A fourth objective is to provide a lithium-ion battery.
[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0006] The first aspect of this invention provides an organic polymer electrode material, which is a polymer containing pyrazine trioxide structural units, with a conjugated carbonyl group as the linking group, and its structural formula is shown in formula (I):
[0007]
[0008] Where R is a conjugated carbonyl group.
[0009] Preferably, R is selected from... One of them.
[0010] More preferably, the organic polymer electrode material has the following structural formulas (I)-(IV):
[0011]
[0012] The second aspect of this invention provides a method for preparing the organic polymer electrode material described in the first aspect, comprising the following steps:
[0013] Tribromopyrazine monomer The organic polymer electrode material is prepared by polymerizing NH2-R-NH2 monomer, which contains diamino and conjugated carbonyl groups.
[0014] Preferably, the tribromopyrazine monomer is prepared by a method comprising the following steps: reacting cyclohexanehexaone octahydrate with 4-bromo-1,2-phenylenediamine to obtain the tribromopyrazine monomer.
[0015] More preferably, the reaction temperature is 100–140°C and the reaction time is 20–28 h.
[0016] More preferably, the molar ratio of the cyclohexanehexaone octahydrate and 4-bromo-1,2-phenylenediamine is 1:(3-4).
[0017] More preferably, the reaction is carried out in a protective atmosphere.
[0018] More preferably, the cyclohexanehexaone octahydrate and 4-bromo-1,2-phenylenediamine are reacted in glacial acetic acid solvent to prepare the tribromotripyrazine monomer.
[0019] Preferably, the process includes the following steps: in the presence of a palladium catalyst, a biphenyl monophosphine ligand, and a base, a tribromopyrazine monomer and a monomer containing a diamino group and a conjugated carbonyl group undergo a polymerization reaction to obtain the organic polymer electrode material.
[0020] More preferably, the palladium catalyst is selected from one or a combination of Pd(dba)2 and Pd(OAc)2.
[0021] More preferably, the molar ratio of the palladium catalyst to the tribromopyrazine monomer is (0.03-0.1):1.
[0022] More preferably, the biphenyl monophosphine ligand is selected from one or more of XPhos, RuPhos, tBuXPhos, SPhos, XPhos, and JohnPhos.
[0023] More preferably, the molar ratio of the biphenyl monophosphine ligand to the tribromopyrazine monomer is (0.08-0.15):1.
[0024] More preferably, the alkali is selected from one or a combination of t-BuOK, t-BuONa.
[0025] More preferably, the molar ratio of the base to the tribromopyrazine monomer is (2-4):1.
[0026] Preferably, the polymerization reaction is carried out under a protective atmosphere.
[0027] More preferably, the protective atmosphere comprises at least one of nitrogen, helium, and argon.
[0028] Preferably, the polymerization reaction temperature is 100–140°C.
[0029] More preferably, the polymerization reaction temperature is 110–130°C.
[0030] Preferably, the polymerization reaction takes 72 to 120 hours.
[0031] More preferably, the polymerization reaction takes 84 to 108 hours.
[0032] More preferably, the polymerization reaction takes 90 to 102 hours.
[0033] Preferably, the molar ratio of the tribromopyrazine monomer to the monomer containing a diamino group and a conjugated carbonyl group is 1:(1-2).
[0034] More preferably, the molar ratio of the tribromopyrazine monomer to the monomer containing a diamino group and a conjugated carbonyl group is 1:(1.3 to 1.7).
[0035] Preferably, the polymerization reaction is carried out in a solvent selected from toluene, xylene, THF, DME, 1,4-dioxane, DMF, NMP, and DMSO.
[0036] Preferably, the process further includes the following steps: after the polymerization reaction, dilute hydrochloric acid and tetrahydrofuran are added and stirred for 4 to 6 hours.
[0037] The third aspect of this invention provides the application of the organic polymer electrode material described in the first aspect in lithium-ion batteries.
[0038] A fourth aspect of the present invention provides a lithium-ion battery, comprising a positive electrode and a negative electrode; the active material of the positive electrode comprises the organic polymer electrode material described in the first aspect.
[0039] Preferably, the positive electrode is prepared by the following steps: the organic polymer electrode material, conductive additive and binder are uniformly dispersed in a solvent and uniformly coated on a current collector, and dried to form a positive electrode film, thereby obtaining the positive electrode.
[0040] The beneficial effects of this invention are:
[0041] This invention provides an organic polymer electrode material, which is an organic conjugated polymer based on hexaazanaphthyl and conjugated carbonyl groups linked by aromatic amines. This organic cathode material contains a nitrogen-rich conjugated structure and abundant C=N and C=O groups as active sites for lithium storage, exhibiting excellent structural stability and high theoretical specific capacity, with a theoretical specific capacity greater than 300 mAh·g. -1 When the organic polymer electrode material provided by this invention is applied to the positive electrode of a lithium-ion battery, it achieves high specific capacity, good rate performance, and good cycle performance, and is expected to be applied in the field of next-generation sustainable, environmentally friendly, and high-energy-density energy storage batteries.
[0042] Specifically, compared with the prior art, the present invention has the following advantages:
[0043] (1) The organic polymer organic electrode material provided by the present invention is an organic polymer material without transition metals, with abundant raw materials, low cost, green and environmentally friendly, and has flexible molecular designability and multiple redox active centers.
[0044] (2) The organic polymer electrode material provided by the present invention has a π-conjugated system and a polyaniline-like structure, which is beneficial to expanding the π electron delocalization and promoting the rapid transfer of electrons, thereby improving the structural stability and rate performance of the material, effectively reducing the dissolution of organic materials in organic electrolytes and improving the conductivity of the material to a certain extent.
[0045] (3) The organic polymer electrode material provided by the present invention has multiple redox active sites, with abundant C=N and C=O groups as active sites for lithium storage, which is beneficial to improving the theoretical specific capacity of organic materials; thereby solving the technical problems of low capacity, easy solubility in organic electrolyte and poor inherent conductivity of existing lithium-ion battery organic electrode materials. Attached Figure Description
[0046] Figure 1 The Fourier transform infrared spectra of the products of Examples 1-4 are shown below; where (a) is HATN-AQ; (b) is HATN-BQ; (c) is HATN-CBD; and (d) is HATN-PTO.
[0047] Figure 2 The solid-state NMR spectra of the products of Examples 1-4 are shown below; where (a) is HATN-AQ; (b) is HATN-BQ; (c) is HATN-CBD; and (d) is HATN-PTO.
[0048] Figure 3 The graph shows the rate performance of half-cells made based on the products of Examples 1-4 at different current densities;
[0049] Figure 4 The half-cell prepared based on the product of Example 1 was tested at a current density of 0.2 A·g. -1 Charge-discharge curves at that time;
[0050] Figure 5 The half-cell prepared based on the product of Example 1 was tested at a current density of 5 A·g. -1 Cyclic performance graph;
[0051] Figure 6 The graph shows the rate performance of the full cell made based on the product of Example 4 at different current densities.
[0052] Figure 7 The full cell prepared based on the product of Example 4 was tested at a current density of 0.5 A·g. -1 Cyclic performance graph. Detailed Implementation
[0053] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials used in the following embodiments can be obtained from conventional commercial channels or prepared and isolated through simple synthesis; unless otherwise specified, the processes employed are conventional processes in the art.
[0054] Example 1
[0055] This embodiment provides an organic polymer electrode material, the specific preparation steps of which are as follows:
[0056]
[0057] S1. Mix 0.94 g (3.01 mmol) of cyclohexanehexanone octahydrate and 1.69 g (9.03 mmol) of 4-bromo-1,2-phenylenediamine, evacuate under vacuum, and backfill with nitrogen. Add 50 mL of glacial acetic acid, evacuate under vacuum, and backfill with nitrogen. Repeat this process three times. Reflux at 120 °C for 24 h under a nitrogen atmosphere. After the reaction is complete, cool to room temperature, filter under vacuum, wash with water and ethanol, and dry under vacuum to obtain tribromopyrazine (HATN-Br).
[0058] S2. In a 50 mL reaction tube, tribromopyrazine (124 mg, 0.20 mmol), 2,6-diaminoanthraquinone (71.4 mg, 0.30 mmol), Pd(dba)2 (7.3 mg, 0.013 mmol), XPhos (10.7 mg, 0.022 mmol), and t-BuONa (50.7 mg, 0.53 mmol) were added sequentially. The reaction tube was evacuated and then backfilled with nitrogen. DMF (9 mL) was then added as a solvent under a nitrogen atmosphere. The resulting mixed solution was evacuated and backfilled with nitrogen for three cycles. The mixture was then heated to 120 °C and reacted for four days. After the reaction was completed, dilute hydrochloric acid and tetrahydrofuran were added and stirred for 5 hours. The resulting solution was filtered under reduced pressure and washed sequentially with water, tetrahydrofuran, and anhydrous ethanol. The collected solid product was placed in a vacuum drying oven and dried overnight at 40 °C to obtain a black product, which is the organic polymer electrode material, denoted as HATN-AQ.
[0059] Example 2
[0060] This embodiment provides an organic polymer electrode material, the specific preparation steps of which are as follows:
[0061]
[0062] S1. Mix 0.94 g of cyclohexanehexanone octahydrate and 1.69 g of 4-bromo-1,2-phenylenediamine, evacuate under vacuum, and backfill with nitrogen. Add 50 mL of glacial acetic acid, evacuate under vacuum, and backfill with nitrogen. Repeat this process three times. Reflux at 120 °C for 24 h under a nitrogen atmosphere. After the reaction is complete, cool to room temperature, filter under vacuum, wash with water and ethanol, and dry under vacuum to obtain tribromopyrazine (HATN-Br).
[0063] S2. In a 50 mL reaction tube, tribromopyrazine (124 mg, 0.20 mmol), 2,5-diaminobenzoquinone (41.4 mg, 0.30 mmol), Pd(dba)2 (7.3 mg, 0.013 mmol), XPhos (10.7 mg, 0.022 mmol), and t-BuONa (50.7 mg, 0.53 mmol) were added sequentially. The reaction tube was evacuated and then backfilled with nitrogen. DMF (9 mL) was then added as a solvent under a nitrogen atmosphere. The resulting mixed solution was evacuated and backfilled with nitrogen for three cycles. The mixture was then heated to 120 °C and reacted for four days. After the reaction was completed, dilute hydrochloric acid and tetrahydrofuran were added and stirred for 5 hours. The resulting solution was filtered under reduced pressure and washed sequentially with water, tetrahydrofuran, and anhydrous ethanol. The collected solid product was placed in a vacuum drying oven and dried overnight at 40 °C to obtain a black product, which is the organic polymer electrode material, denoted as HATN-BQ.
[0064] Example 3
[0065] This embodiment provides an organic polymer electrode material, the specific preparation steps of which are as follows:
[0066]
[0067] S1. Mix 0.94 g of cyclohexanehexanone octahydrate and 1.69 g of 4-bromo-1,2-phenylenediamine, evacuate under vacuum, and backfill with nitrogen. Add 50 mL of glacial acetic acid, evacuate under vacuum, and backfill with nitrogen. Repeat this process three times. Reflux at 120 °C for 24 h under a nitrogen atmosphere. After the reaction is complete, cool to room temperature, filter under vacuum, wash with water and ethanol, and dry under vacuum to obtain tribromopyrazine (HATN-Br).
[0068] S2. In a 50 mL reaction tube, tribromopyrazine (124 mg, 0.20 mmol), 3,4-diaminocyclobut-3-ene-1,2-dione (33.6 mg, 0.30 mmol), Pd(dba)2 (7.3 mg, 0.013 mmol), XPhos (10.7 mg, 0.022 mmol), and t-BuONa (50.7 mg, 0.53 mmol) were added sequentially. The reaction tube was evacuated and then backfilled with nitrogen. DMF (9 mL) was then added as a solvent under a nitrogen atmosphere. The resulting mixed solution was evacuated and backfilled with nitrogen for three cycles. The mixture was then heated to 120 °C and reacted for four days. After the reaction was completed, dilute hydrochloric acid and tetrahydrofuran were added and stirred for 5 hours. The resulting solution was filtered under reduced pressure and washed sequentially with water, tetrahydrofuran, and anhydrous ethanol. The collected solid product was placed in a vacuum drying oven and dried overnight at 40 °C to obtain a black product, which is the organic polymer electrode material, denoted as HATN-CBD.
[0069] Example 4
[0070] This embodiment provides an organic polymer electrode material, the specific preparation steps of which are as follows:
[0071]
[0072] S1. Mix 0.94 g of cyclohexanehexanone octahydrate and 1.69 g of 4-bromo-1,2-phenylenediamine, evacuate under vacuum, and backfill with nitrogen. Add 50 mL of glacial acetic acid, evacuate under vacuum, and backfill with nitrogen. Repeat this process three times. Reflux at 120 °C for 24 h under a nitrogen atmosphere. After the reaction is complete, cool to room temperature, filter under vacuum, wash with water and ethanol, and dry under vacuum to obtain tribromopyrazine (HATN-Br).
[0073] S2. In a 50 mL reaction tube, add tribromopyrazine (124 mg, 0.20 mmol), 2,7-diaminopyrene-4,5,9,10-tetraone (87.7 mg, 0.30 mmol), Pd(dba)2 (7.3 mg, 0.013 mmol), XPhos (10.7 mg, 0.022 mmol), and t-BuONa (50.7 mg, 0.53 mmol) sequentially. Evacuate the reaction tube and then backfill with nitrogen. Then, DMF (9 mL) was added as a solvent under a nitrogen atmosphere; the resulting mixed solution was evacuated and backfilled with nitrogen, and this process was repeated three times. Then, the mixture was heated to 120 °C and reacted for four days. After the reaction was completed, dilute hydrochloric acid and tetrahydrofuran were added and stirred for 5 hours. The resulting solution was filtered under reduced pressure and washed successively with water, tetrahydrofuran and anhydrous ethanol. The collected solid product was placed in a vacuum drying oven and dried overnight at 40 °C to obtain a black product, namely the organic polymer electrode material, denoted as HATN-PTO.
[0074] Material characterization
[0075] The organic polymers prepared in Examples 1-4 were subjected to Fourier transform infrared spectroscopy and solid-state nuclear magnetic resonance characterization. The results are as follows: Figure 1 and Figure 2 As shown.
[0076] Figure 1 The Fourier transform infrared spectra of the products from Examples 1-4 are shown below. Figure 1 As shown, HATN-3Br at 665cm -1 The strong stretching vibration absorption peak of the C-Br bond is observed at 3100-3500 cm⁻¹. After the reaction is complete, the C-Br bond absorption peak almost completely disappears, indicating that the C-Br bond breaks during the reaction. Meanwhile, monomers containing diamino groups (AQ-2NH₂, BQ-2NH₂, CBD-2NH₂, PTO-2NH₂) show absorption peaks at 3100-3500 cm⁻¹. -1The product exhibits a distinct stretching vibration absorption peak of the -NH bond. After the reaction is complete, the absorption peak of the -NH bond almost completely disappears. Furthermore, new C=O, C=N, and CN bonds appear in the products of Examples 1-4. The above demonstrates the successful synthesis of aromatic amine linkages and the completion of the polymerization reaction.
[0077] Figure 2 The solid-state NMR spectra of the products of Examples 1-4 are shown below. Figure 2 As shown, at approximately 180 ppm, the products of Examples 1-4 all exhibited a distinct peak of the C=O functional group, while the peak at approximately 140-150 ppm corresponded to the CNH bond, further verifying the successful synthesis of the aromatic amine linkage and the completion of the polymerization reaction.
[0078] Experimental Test
[0079] 1. The organic positive electrode for lithium-ion batteries is prepared according to the following steps: The organic polymers prepared in Examples 1-4 are ground thoroughly and uniformly with Ketjen Black (600JD) and PVDF in a mortar. Then, NMP solvent is added and grinding is continued to obtain an electrode slurry with a metallic luster and uniformity. The obtained electrode slurry is coated on carbon-coated aluminum foil, and then dried in a 65°C forced-air drying oven for 6 hours. After that, it is transferred to a 65°C vacuum drying oven for 6-10 hours to obtain the organic positive electrode sheet for lithium-ion batteries.
[0080] Using lithium metal as the negative electrode, Celgard 2325 as the separator, 1M LiTFSI, DOL:DME = 1:1 (v:v), and 1% LiNO3 as the electrolyte, a CR2032 type coin cell was assembled.
[0081] Using pre-lithiated graphite electrodes as the negative electrode, Celgard 2325 as the separator, 1M LiPF6, EC:DEC = 1:1 (v:v), and 5% FEC as the electrolyte, a CR2032 coin cell was assembled.
[0082] 2. Perform electrochemical performance tests on the prepared coin cells. Figure 3 The graph shows the rate performance of half-cells made from organic cathode materials HATN-AQ, HATN-BQ, HATN-CBD, or HATN-PTO at different current densities. The graphs show that HATN-PTO exhibits the best rate performance, even at 20 A·g⁻¹. -1 Even at high current densities, it still has 208.7 mAh·g. -1 High discharge specific capacity. Figure 4 The half-cell was prepared by HATN-AQ at 0.2 A·g -1 The charge-discharge curves at current density. Figure 5 The half-cell was prepared by HATN-AQ at 5 A·g-1 The cycling performance at current density is shown in the graph. After 1000 cycles, it still retains 131.2 mAh·g. -1 It has a high discharge specific capacity and good cycle stability. Figure 6 The graph shows the rate performance of the full cell fabricated by HATN-PTO at different current densities, starting at a current density of 0.2 A·g. -1 It has a capacity of 227.3 mAh g. -1 High discharge specific capacity, even at 5 A·g -1 Even at high current densities, it still has 107.2 mAh·g. -1 The specific discharge capacity. Figure 7 The full cell was prepared by HATN-PTO at 0.5 A·g -1 The cycling performance at current density is shown in the graph. After 200 cycles, it still retains 99.1 mAh·g. -1 It has a high discharge specific capacity and good cycle stability.
[0083] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. An organic polymer electrode material, characterized in that, The organic polymer electrode material is a polymer containing pyrazine structural units, with conjugated carbonyl groups as linking groups, and its structural formula is shown in formula (I): Equation (Ⅰ); Wherein, R is selected from , , , One of them; The preparation method of the organic polymer electrode material includes the following steps: In the presence of a palladium catalyst, biphenyl monophosphine ligands and a base, tribromopyrazine monomers and NH2-R-NH2 monomers undergo a polymerization reaction to obtain the organic polymer electrode material. The biphenyl monophosphine ligand is selected from one or more of XPhos, RuPhos, tBuXPhos, SPhos, and JohnPhos.
2. The method for preparing the organic polymer electrode material according to claim 1, characterized in that, Includes the following steps: Tribromopyrazine monomer The organic polymer electrode material is prepared by polymerizing NH2-R-NH2 monomer, which contains diamino and conjugated carbonyl groups.
3. The method for preparing the organic polymer electrode material according to claim 2, characterized in that, The tribromopyrazine monomer is prepared by a method comprising the following steps: reacting cyclohexanehexaone octhydrate with 4-bromo-1,2-phenylenediamine to obtain the tribromopyrazine monomer.
4. The method for preparing the organic polymer electrode material according to claim 2, characterized in that, The polymerization reaction is carried out under a protective atmosphere.
5. The method for preparing the organic polymer electrode material according to claim 2, characterized in that, The polymerization reaction is carried out at a temperature of 100~140℃.
6. The method for preparing the organic polymer electrode material according to claim 2, characterized in that, The molar ratio of the tribromopyrazine monomer to the monomer containing a diamino group and a conjugated carbonyl group is 1:(1~2).
7. The application of the organic polymer electrode material according to claim 1 in lithium-ion batteries.
8. A lithium-ion battery, characterized in that, It includes a positive electrode and a negative electrode; the active material of the positive electrode includes the organic polymer electrode material according to claim 1.