Organic polymer and preparation method thereof, electrode material, electrode plate and battery

Abstract

The invention relates to an electrode material, in particular to an organic polymer and a preparation method thereof, an electrode material, an electrode plate and a battery. The structure of the organic polymer is shown in the formula I, the organic polymer has low solubility in an aqueous battery, and the cycling stability is greatly improved. The electrode material has a unique bipolar zinc ion storage mechanism, when the battery is fully charged completely, an azo functional group and an ortho-phenolic hydroxyl group are coordinated with zinc ions to form a metal heterocyclic polymer, in the subsequent discharge process, a heterocyclic ring is opened, and an azo group can be used as a redox center to be subjected to reversible reaction with Zn < 2 + > ions. The invention provides a solution for improving the structural stability and long cycle performance of the azo organic material in the aqueous battery, and also provides another distinctive thought for the storage mode of Zn < 2 + > in the aqueous battery. # imgabs0 #

Description

Technical Field

[0001] The present application relates to the technical field of electrode materials, and in particular to an organic polymer and a preparation method thereof, an electrode material, an electrode plate and a battery. Background Art

[0002] With the development and application of new energy technologies, the market demand for high-energy, long-cycle, high-safety, and low-cost batteries is increasing. Lithium-ion batteries (LIBs) have high energy density and long cycle life and have been widely used in portable electronic products and electric vehicle markets. However, limited lithium resources are bound to face shortages, and the high preparation cost has also seriously hindered the further development of LIBs. Sodium-ion batteries (SIBs) and potassium-ion batteries (KIBs) have lower raw material costs, but high manufacturing costs and flammable safety hazards.

[0003] Aqueous zinc ion batteries (AZIBs) provide a new option, with readily available raw materials, higher safety and lower preparation cost [Active Materials for Aqueous Zinc Ion Batteries: Synthesis, Crystal Structure, Morphology, and Electrochemistry (Active Materials for Aqueous Zinc Ion Batteries: Synthesis, Crystal Structure, Morphology, and Electrochemistry). Chem. Rev. 2020, 120, 7795-7866]. At present, a series of inorganic aqueous zinc ion batteries have been developed, using inorganic materials such as manganese, vanadium, molybdenum and Prussian blue analogs as positive electrode materials. These inorganic materials may produce volume expansion under deep charge / discharge conditions, and there is a risk of structural collapse, resulting in greatly reduced capacity and poor cycle stability [Ultralong cycle stability of aqueous zinc-ion batteries with zinc vanadium oxide cathodes (Ultralong cycle stability of aqueous zinc-ion batteries with zinc vanadium oxide cathodes). Sci. Adv. 2019, 5 (10): eaax4279]. Therefore, it is necessary to explore and develop highly active and highly stable positive electrode materials.

[0004] Organic materials have attracted extensive attention in the past decade due to their extensive structural design capabilities at the molecular level, which can systematically manipulate electrochemical activity and redox kinetics for efficient energy storage. Despite significant progress in organic compounds, the practical application of these organic compounds in batteries is still limited by sluggish reaction kinetics, low cycling stability, and limited capacity.

[0005] In view of this, the technical solution of this application is proposed. Summary of the invention

[0006] Based on this, the purpose of the present application includes providing an organic polymer and a preparation method thereof, an electrode material, an electrode plate and a battery. The organic polymer and the electrode material have high stability, low solubility in aqueous batteries, strong cycle stability and good electrochemical properties.

[0007] The first aspect of the present application provides an organic polymer, whose structure is shown in Formula I:

[0008]

[0009] Among them, n is 10 to 200000.

[0010] In some embodiments, the organic polymer has at least one of the following characteristics:

[0011] (1) the organic polymer has an X-ray photoelectron spectroscopy spectrum showing an N(1s) peak at about 400 eV;

[0012] (2) The organic polymer has a -1 A characteristic infrared spectrum at

[0013] (3) The organic polymer has a -1 Characteristic Raman spectrum.

[0014] The second aspect of the present application provides a method for preparing an organic polymer, which comprises the following steps:

[0015] Dissolving the first 4-aminophenol in an acid solution, adding sodium nitrite to carry out a diazotization reaction, and adjusting the pH of the reaction solution to 6.8-7.2 after the diazotization reaction to obtain a first solution;

[0016] Dissolving a second 4-aminophenol in a sodium carbonate solution to prepare a second solution;

[0017] The second solution is added to the first solution to carry out a coupling reaction.

[0018] In some embodiments, in the preparation method, the product of the coupling reaction includes the organic polymer provided in the first aspect of the present application.

[0019] In some embodiments, in the preparation method, the molar ratio of the first 4-aminophenol to the sodium nitrite is 1:(2-2.2);

[0020] The molar ratio of the first 4-aminophenol to the second 4-aminophenol is 1:(0.8-1.2).

[0021] In some embodiments, in the preparation method, the pH of the acid solution is 1 to 2;

[0022] The mass volume ratio of the first 4-aminophenol to the acid solution is 1 g: (20-40) mL.

[0023] In some embodiments, in the preparation method, the pH of the second solution is 6.8-7.2.

[0024] In some embodiments, in the preparation method, the temperature of the diazotization reaction is -5°C to 5°C; and / or

[0025] The coupling reaction temperature is -5°C to 5°C; and / or

[0026] The coupling reaction time is 24h to 36h.

[0027] The third aspect of the present application provides an electrode material, wherein the electrode active substance of the electrode material is the organic polymer provided in the first aspect of the present application, or the organic polymer prepared by the preparation method provided in the second aspect of the present application.

[0028] The fourth aspect of the present application provides an electrode plate, comprising the electrode material provided in the third aspect of the present application.

[0029] The fifth aspect of the present application provides a battery, comprising the electrode sheet provided in the fourth aspect of the present application;

[0030] Preferably, the battery is a zinc ion battery.

[0031] The organic polymer of the present application has a low solubility in aqueous batteries, which greatly improves the cycle stability. The electrode material of the present application has a unique bipolar zinc ion storage mechanism. When the battery is fully charged, the azo functional group and the adjacent phenolic hydroxyl group coordinate with the zinc ion to form a metal heterocyclic polymer. In the subsequent discharge process, the heterocyclic ring opens, and the azo group can act as a redox center to react with Zn 2+ This not only provides a solution for improving the structural stability and long cycle performance of azo organic materials in aqueous batteries, but also for Zn 2+ Storage in aqueous batteries offers a different approach.

[0032] The present application uses a diazo coupling method to synthesize an azo material for use as an electrode material in an aqueous zinc ion battery. In addition to being able to work in an aqueous zinc ion battery system, the material also has a unique bipolar zinc ion storage mechanism. The material can be tested in an aqueous zinc ion battery for about 1,000 cycles without capacity decay. The unique zinc ion storage mechanism can also contribute a portion of the capacity to the aqueous zinc ion battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 is the infrared spectrum of the organic polymer obtained in Example 1;

[0035] Figure 2 is the Raman spectrum of the organic polymer obtained in Example 1;

[0036] Figure 3 The zinc ion battery prepared in Example 1 was heated to 1M Zn(OTF) 2 Cyclic voltammetry curves at different scan rates in solution;

[0037] Figure 4 The long cycle results of the zinc ion battery prepared in Example 1 and the zinc ion battery prepared in Comparative Example 1 are compared at a current density of 2Ag-1;

[0038] Figure 5 The zinc ion battery prepared in Example 1 was heated to 1M Zn(OTF) 2 Rate performance diagram at different current densities of 0.5 to 10A g-1 in solution. DETAILED DESCRIPTION

[0039] The present application will be further described below in conjunction with the embodiments, examples and accompanying drawings. It should be understood that these examples are only used to illustrate the present application and are not intended to limit the scope of the present application. In addition, it should be understood that after reading the content taught in the present application, those skilled in the art may make various changes or modifications to the present application, and these equivalent forms also fall within the scope of protection of the claims attached to the present application.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0041] the term

[0042] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0043] The terms "and / or", "or / and", and "and / or" used in this article include any one of two or more related listed items, and also include any and all combinations of related listed items, and the arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it should be understood that in this application, the technical solution undoubtedly includes technical solutions that are all connected by "logical and", and undoubtedly includes technical solutions that are all connected by "logical or". For example, "A and / or B" includes three parallel solutions of A, B and A+B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, the technical solution that is all connected by "logical OR"), and also includes any and all combinations of A, B, C, and D, that is, the combination of any two or any three of A, B, C, and D, and also includes the combination of four of A, B, C, and D (that is, the technical solution that is all connected by "logical AND").

[0044] In this application, the term "about" is generally used in conjunction with a numerical value and can refer to a set or range of values. For example, "about X" includes a range of values ​​of ±20%, ±10%, ±5%, ±2%, ±1%, ±0.5%, ±0.2%, or ±0.1% of X, where X is a numerical value.

[0045] In the present application, the terms "first", "second", "third", "fourth", etc. in "the first aspect", "the second aspect", "the third aspect", "the fourth aspect", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0046] Herein, "preferred", "preferable", "better", etc. are only used to describe implementation methods or examples with better effects. It should be understood that they do not constitute limitations on the scope of protection of this application.

[0047] In the present application, "further", "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present application.

[0048] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0049] In the present application, when it comes to numerical intervals (i.e., numerical ranges), unless otherwise specified, the optional numerical distribution is considered continuous within the above numerical interval, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical range, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to integers within the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges included therein.

[0050] The temperature parameters in this application, unless otherwise specified, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0051] In the present application, weight may be μg, mg, g, kg or other mass units known in the chemical industry.

[0052] In a first aspect of the present application, an organic polymer is disclosed. The organic polymer has high stability, low solubility in aqueous batteries, strong cycle stability, and good electrochemical properties.

[0053] In some embodiments, the organic polymer structure is as shown in Formula I:

[0054]

[0055] Among them, n is 10 to 200000.

[0056] Optionally, n is selected from 20 to 1000, 50 to 10000, 1000 to 10000, 5000 to 20000, 10000 to 200000, 100000 to 200000, etc.

[0057] The organic polymer has a special azo functional group. The azo functional group (-N=N-) is an important functional group in chemistry and materials science, with characteristics such as narrow band gap, Lewis base properties and redox activity. Applying it to the electrode material (azo electrode material) of organic batteries can improve the capacity and redox reaction activity of the battery. At present, it is still challenging to achieve the cycle stability and high rate performance of azo electrode materials.

[0058] The organic polymer of the present invention has a stable structure in the aqueous battery environment, which greatly improves the cycle stability of the battery. The azo organic polymer has a unique bipolar zinc ion storage mechanism. When fully charged, the azo functional group and the adjacent phenolic hydroxyl group coordinate with the zinc ion to form a metal heterocyclic polymer. In the subsequent discharge process, the heterocyclic ring opens, and the azo group can act as a redox center to react with Zn 2+ The ions undergo reversible reactions, and this unique storage mechanism effectively improves the battery's cycle stability and electrochemical performance.

[0059] In some embodiments, the organic polymer has at least one of the following characteristics:

[0060] (1) The organic polymer has an X-ray photoelectron spectroscopy spectrum showing an N(1s) peak at about 400 eV;

[0061] (2) Organic polymers have a -1 A characteristic infrared spectrum at

[0062] (3) Organic polymers have a wavelength of about 1500 cm -1 Characteristic Raman spectrum.

[0063] The second aspect of the present application relates to a method for preparing an organic polymer. The organic polymer prepared by the preparation method has high structural stability and low solubility in aqueous batteries, thereby greatly improving the cycle stability.

[0064] The method for preparing an organic polymer provided in the second aspect of the present application can be used to prepare an organic polymer of formula (I).

[0065] In some embodiments, the method for preparing an organic polymer comprises the following steps:

[0066] Dissolving the first 4-aminophenol in an acid solution, adding sodium nitrite to carry out a diazotization reaction, and adjusting the pH of the reaction solution to 6.8-7.2 after the diazotization reaction to obtain a first solution;

[0067] Dissolving a second 4-aminophenol in a sodium carbonate solution to prepare a second solution;

[0068] The second solution is added to the first solution to perform a coupling reaction.

[0069] In some embodiments, in the method for preparing an organic polymer, the product of the coupling reaction includes the organic polymer provided in the first aspect of the present application, that is, the organic polymer of formula (I).

[0070] In some embodiments, the molar ratio of the first 4-aminophenol to sodium nitrite is 1:(2-2.2);

[0071] The molar ratio of the first 4-aminophenol to the second 4-aminophenol is 1:(0.8-1.2).

[0072] In some embodiments, the pH of the acid solution is 1 to 2;

[0073] The mass volume ratio of the first 4-aminophenol to the acid solution is 1 g: (20-40) mL.

[0074] In some embodiments, the pH of the second solution is 6.8-7.2.

[0075] In some embodiments, the temperature of the diazotization reaction is -5°C to 5°C; and / or

[0076] The temperature of the coupling reaction is -5°C to 5°C; and / or

[0077] The coupling reaction time is 24h to 36h.

[0078] The coupling reaction of the present application requires at least 24 hours to obtain the desired degree of polymerization. When the coupling time is short, such as less than 18 hours, the obtained product has the disadvantage of a weak degree of polymerization, which affects the electrochemical performance. When the reaction time is too long, such as more than 40 hours, the obtained product has the disadvantage of possibly forming other by-products. Preferably, the coupling reaction time is 24 hours to 30 hours, and more preferably 24 hours to 26 hours.

[0079] In some embodiments, after the coupling reaction is completed, the mixture is washed with water, methanol and water in sequence, the product is extracted by vacuum filtration, and the extracted product is freeze-dried to obtain a reddish-brown solid;

[0080] Furthermore, the drying time is 12 hours to 24 hours.

[0081] In the third aspect of the present application, an electrode material is provided, wherein the electrode active substance of the electrode material is the organic polymer provided in the first aspect of the present application, or the organic polymer prepared by the preparation method provided in the second aspect of the present application.

[0082] In a fourth aspect of the present application, an electrode plate is provided, which includes the electrode material provided in the third aspect of the present application.

[0083] In a fifth aspect of the present application, a battery is provided, comprising the electrode sheet provided in the fourth aspect of the present application;

[0084] Preferably, the battery is a zinc ion battery, and more preferably, the battery is an aqueous zinc ion battery.

[0085] The following are some specific embodiments.

[0086] For experimental parameters not specified in the following specific embodiments, reference is made to the instructions given in the present application document, and reference may also be made to experimental manuals in the art or other experimental methods known in the art, or to experimental conditions recommended by manufacturers.

[0087] The raw materials and reagents involved in the following specific examples can be obtained from commercial sources, or can be prepared by those skilled in the art according to known methods.

[0088] Example 1

[0089] 1. Preparation of batteries

[0090] (1) Preparation of organic polymers

[0091] 1) Dissolve 4-aminophenol (0.3 g, 2.75 mmol) in a hydrochloric acid solution and stir at 0-5°C for 15 minutes; then add an aqueous solution of sodium nitrite (0.38 g, 5.58 mmol) and continue stirring at 0-5°C for 30 minutes;

[0092] Then slowly add Na 2 CO 3 aqueous solution, and make the pH of the mixed solution be 6.8-7.2 to obtain the first solution; Na 2 CO 3 The pH of the aqueous solution is weakly alkaline;

[0093] 2) Dissolve the second 4-aminophenol (2.7 mmol, 0.3 g) in Na 2 CO 3 aqueous solution to obtain a second solution; Na 2 CO 3 Aqueous solution (0.86 g, 8.1 mmol);

[0094] 3) Add the second solution to the first solution and mix, stir for 24 hours after the addition is complete, then wash the reaction solution with water, methanol and water in sequence, extract the product by vacuum filtration, and freeze-dry the extracted product for 12 hours to obtain a reddish-brown solid product.

[0095] The reddish brown solid was taken for structural identification, and the identification items included infrared spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy analysis. Figure 1is the infrared spectrum of organic polymers. Figure 1 The organic polymer has a wavelength of about 1500 cm -1 The characteristic infrared spectrum at corresponds to the group (N=N) in the structure; Figure 2 is the Raman spectrum of organic polymers. Figure 2 The organic polymer has a wavelength of about 1500 cm -1 The organic polymer has a characteristic Raman spectrum at , which corresponds to the group (N=N) in the structure; the X-ray photoelectron spectroscopy analysis results show that the organic polymer has an X-ray photoelectron spectroscopy analysis spectrum showing an N (1s) peak at about 400 eV.

[0096] (2) Preparation of azo electrode materials

[0097] The obtained organic polymer is used as the electrode active material to prepare the corresponding electrode material. The specific preparation steps include: preparing the above-mentioned azo material, binder and conductive carbon black into a uniform slurry and coating it on the carbon cloth current collector with a coating thickness of 50μm-100μm; after drying, the electrode plate of the battery is obtained. Among them, the mass ratio of the battery active material, conductive carbon black and binder is 4:4:2, the binder is N-methylpyrrolidone, and the conductive carbon black is Keqin black.

[0098] (3) Preparation of aqueous zinc ion batteries

[0099] The electrode sheet prepared in step (2) is used to assemble an aqueous zinc ion battery, which is a button battery, the positive electrode is an azo-based electrode material, the negative electrode is a zinc sheet, and the electrolyte is 1MZn(OTF) 2 , the diaphragm is glass fiber.

[0100] 2. Battery performance test

[0101] The button cell obtained in step (3) was subjected to a battery performance test: a CV test at different scan rates was performed on a Chenhua electrochemical workstation in a voltage range of 0.1 V to 1.5 V. The test results are shown in FIG. Figure 3 .

[0102] The button cell obtained in step (3) was subjected to electrochemical testing. The test results are as follows: Figure 4 .

[0103] Comparative Example 1

[0104] The button cell was prepared in the same manner as in Example 1, except that the electrode material used was commercially available azobenzene. The electrode pieces were prepared in the same manner and then assembled into button cells. The electrochemical test was performed on a blue light. The test results are shown in FIG. Figure 5 .

[0105] All documents mentioned in this application are cited as references in this application, just as each document is cited as reference separately. Unless they conflict with the application purpose and / or technical solution of this application, the cited documents involved in this application are cited with all contents and all purposes. When the cited documents are involved in this application, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited documents are also cited. When the cited documents are involved in this application, the examples and preferred methods of the cited relevant technical features can also be incorporated into this application as references, but are limited to the implementation of this application. It should be understood that when the cited content conflicts with the description in this application, the present application shall prevail or be modified adaptively according to the description of this application.

[0106] The technical features of the above-mentioned implementation modes and examples can be combined in any appropriate manner. To make the description concise, not all possible combinations of the technical features in the above-mentioned implementation modes and examples are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0107] The above-described embodiments only express several implementation methods of the present application, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for those of ordinary skill in the art, without departing from the concept of the present application, several variations and improvements can also be made, which all belong to the protection scope of the present application. In addition, it should be understood that after reading the above-mentioned teaching content of the present application, those skilled in the art can make various changes or modifications to the present application, and the equivalent forms obtained also fall within the protection scope of the present application. It should also be understood that the technical solutions obtained by those skilled in the art on the basis of the technical solutions provided in the present application through logical analysis, reasoning or limited experiments are all within the protection scope of the claims attached to the present application. Therefore, the protection scope of the patent of the present application shall be based on the attached claims, and the description and drawings may be used to explain the contents of the claims.

Claims

1. An organic polymer, the structure of which is shown in Formula I: in, n is 10 to 200,000.

2. The organic polymer according to claim 1, characterized in that Has at least one of the following characteristics: (1) the organic polymer has an X-ray photoelectron spectroscopy spectrum showing an N(1s) peak at about 400 eV; (2) The organic polymer has a -1 A characteristic infrared spectrum at (3) The organic polymer has a -1 Characteristic Raman spectrum.

3. A method for preparing an organic polymer, characterized in that: The steps include: Dissolving the first 4-aminophenol in an acid solution, adding sodium nitrite to carry out a diazotization reaction, and adjusting the pH of the reaction solution to 6.8-7.2 after the diazotization reaction to obtain a first solution; Dissolving a second 4-aminophenol in a sodium carbonate solution to prepare a second solution; The second solution is added to the first solution to carry out a coupling reaction.

4. The preparation method according to claim 3, characterized in that: The product of the coupling reaction comprises the organic polymer according to claim 1 or 2.

5. The preparation method according to claim 3 or 4, characterized in that: The molar ratio of the first 4-aminophenol to the sodium nitrite is 1:(2-2.2); The molar ratio of the first 4-aminophenol to the second 4-aminophenol is 1:(0.8-1.2).

6. The preparation method according to claim 3 or 4, characterized in that: The pH of the acid solution is 1 to 2; The mass volume ratio of the first 4-aminophenol to the acid solution is 1 g: (20-40) mL.

7. The preparation method according to claim 3 or 4, characterized in that: The pH of the second solution is 6.8-7.

2.

8. The preparation method according to claim 3 or 4, characterized in that: The temperature of the diazotization reaction is -5°C to 5°C; and / or The coupling reaction temperature is -5°C to 5°C; and / or The coupling reaction time is 24h to 36h.

9. An electrode material, characterized in that: The electrode active substance of the electrode material is the organic polymer according to claim 1 or 2, or the organic polymer prepared by the preparation method according to any one of claims 3 to 8.

10. An electrode plate, characterized in that: Comprising the electrode material according to claim 9.

11. A battery, characterized in that: The electrode sheet comprising the electrode sheet according to claim 10; Preferably, the battery is a zinc ion battery.

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