Crosslinking aniline-based polymer and preparation method and application thereof

Abstract

The application discloses a crosslinked aniline polymer and a preparation method and application thereof. The aniline polymer has a structural formula as shown in the specification, wherein A is selected from any three of R 1～6 , and is connected to -N in the structural formula by a chemical bond; the rest of R 1～6 is at least one of -H, -NH2, -CH3 and aromatic amine; wherein any three of R 7～21 are connected to -N in the structural formula by a chemical bond; and the rest of R 7～21 is at least one of -H, -NH2, -CH3 and aromatic amine. The aniline polymer is a crosslinked polymer, has good stability, can realize high-voltage properties, and can guarantee the stability of a battery under high voltage when the aniline polymer is used as a positive electrode material, thereby improving the comprehensive performance of the battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a cross-linked aniline polymer and a preparation method and application thereof. BACKGROUND

[0002] Batteries, as an important energy storage device in modern society, have penetrated into various industries, from portable electronic devices to electric vehicles, to large-scale energy storage systems. The application of batteries has been extremely widespread. With the increasing demand for energy worldwide, especially in the context of the rise of renewable energy and electric transportation, the demand for batteries has also shown explosive growth. In the current commercialized lithium battery field, the positive electrode material is mainly composed of inorganic metal oxides, such as LiCoO2 (lithium cobalt oxide), LiMn2O4 (lithium manganese oxide), and LiFePO4 (lithium iron phosphate), etc. These materials are widely used in various electronic products and electric vehicles. However, the production process of these inorganic metal oxide materials relies on some scarce and non-renewable metal resources, which poses a serious challenge to the sustainable development of the battery industry. Especially in the context of strategic protection of metal resources in various countries, the cost of scarce raw materials is gradually rising, leading to increasing production costs. Therefore, developing low-cost and sustainable lithium battery positive electrode materials has become an important direction of current battery technology research.

[0003] The basic working principle of a battery is to transfer ions and electrons between the positive and negative electrodes through electrochemical reactions, thereby achieving energy storage and release. The positive electrode material is a key component in the battery, which is responsible for storing and releasing the charge of the battery, so its performance directly determines the key indicators of the battery, such as energy density, charge and discharge efficiency, cycle life, etc. Currently, the positive electrode material of commercialized lithium batteries is mainly composed of inorganic metal oxides, but with the increasing resource constraints and environmental protection demands, scientists have begun to focus on the potential of organic materials as positive electrode materials. Compared with inorganic materials, organic materials not only can provide competitive performance advantages, but also meet the requirements of green and sustainable development.

[0004] Compared with inorganic materials, the application of organic materials in batteries is particularly unique. Organic materials refer to compounds composed of carbon, hydrogen, oxygen, nitrogen, etc., which exist widely in nature. Compared with inorganic materials, organic materials usually have structural diversity, and their structural properties can be controlled through synthesis, giving them different electrochemical properties. Because the raw materials of organic materials are widely available and relatively low in cost, they provide a green solution to replace traditional metal materials, especially in battery positive electrode materials, which have great potential. By designing organic molecules with high electrical conductivity and high capacity, researchers can develop excellent organic battery materials, which not only solve the problem of scarcity of metal resources, but also reduce production costs.

[0005] In addition to the above advantages, organic materials generally also have lighter mass and better flexibility, which provides new possibilities for the lightweight and flexible development of batteries. In particular, in portable and wearable electronic devices, the lightness and flexibility of the battery are particularly important. For example, future smart watches, smart glasses and other devices may use batteries based on organic positive electrode materials to meet the high requirements for battery performance while improving comfort and convenience. In summary, organic materials provide a new direction for the development of battery technology, both in line with the trend of green environmental protection and able to meet diverse technical needs.

[0006] However, despite the excellent performance of organic positive electrode materials in many aspects, current organic positive electrode materials still have the problem of instability under high voltage conditions. This problem is mainly caused by the chemical stability limitations of the organic material itself. At a higher voltage, the positive electrode material of the battery will undergo an oxidation reaction, and the organic molecules may react adversely with the electrolyte, leading to decomposition or degradation, thereby reducing the overall performance of the battery. This is one of the main challenges faced by organic materials in high voltage environments.

[0007] Therefore, it is urgent to develop an organic positive electrode material that is stable under high voltage. SUMMARY

[0008] The purpose of the present application is to provide an aniline-based polymer that is stable under high voltage.

[0009] The first aspect of the present application is to:

[0010] An aniline-based polymer is provided. The aniline-based polymer is synthesized from 5,5-dimethyl-1,3-bis(oxymethylene methyl)imidazolidine-2,4-dione and an aniline-based compound.

[0011] The second aspect of the present application is to:

[0012] A preparation method of an aniline-based polymer is provided. The preparation method prepares the aniline-based polymer by a three-step heating method.

[0013] The third aspect of the present application is to:

[0014] The application of the aniline-based polymer.

[0015] The present application also provides a positive electrode material.

[0016] Specifically, the technical scheme adopted according to the first aspect of the present application is:

[0017] An aniline-based polymer has the following structural formula:

[0018]

[0019] wherein A is selected from

[0020] wherein R 1～6 of any three are and are chemically bonded to the -N in the structure, and the remaining R 1～6 are at least one of -H, -NH2, -CH3, aromatic amine;

[0021] wherein R 7～21 of any three are and are chemically bonded to the -N in the structure, and the remaining R 7～21 are at least one of -H, -NH2, -CH3, aromatic amine.

[0022] According to an embodiment of the present application, one of the technical solutions has at least one of the following advantages or beneficial effects:

[0023] The aniline polymer has a cross-linked structure, has good stability, and can realize high-voltage properties.

[0024] The present application describes the structure of the group used in the structure formula represents the connection with other fragments, groups through the site.

[0025] According to an embodiment of the present application, R 7～21 of any three are and are chemically bonded to the -N in the structure, and the remaining R 7～21 are at least one of -H, -NH2, -CH3.

[0026] According to an embodiment of the present application, the structure of formula I includes one of them.

[0027] According to an embodiment of the present application, the structure of formula II includes one of them.

[0028] According to an embodiment of the present application, the structure formula is:

[0029] wherein the terminal wavy line in XA1 and XA2 indicates a cycle to the existing structure represented.

[0030] The XA1 or XA2 molecule contains a large number of aniline groups, and because the redox potential of the aniline group is greater than 3.5V, it is beneficial to improve the high voltage resistance of the aniline polymer; the XA1 or XA2 molecule contains a large number of aniline groups, which is one of the key factors that the aniline polymer can be used as an excellent positive electrode material.

[0031] Specifically, the technical scheme adopted according to the second aspect of the present application is:

[0032] A method for preparing the aniline polymer, comprising the following steps:

[0033] Mixing 5,5-dimethyl-1,3-bis(oxymethyl)imidazolidine-2,4-dione and aniline compounds in a solvent, and heating and cross-linking to obtain the aniline polymer.

[0034] According to an embodiment of the present application, one of the technical schemes has at least one of the following advantages or beneficial effects:

[0035] The 5,5-dimethyl-1,3-bis(oxymethyl)imidazolidine-2,4-dione is easy to cross-link with aniline compounds, so that the preparation method of the present application is simple to operate and is helpful for large-scale industrial production. In addition, the product of cross-linking of 5,5-dimethyl-1,3-bis(oxymethyl)imidazolidine-2,4-dione and aniline compounds has a unique stable structure, which endows the aniline polymer with the property of high voltage resistance.

[0036] According to an embodiment of the present application, the aniline compound comprises one of the following structural formulas:

[0037]

[0038] According to an embodiment of the present application, the molar ratio of 5,5-dimethyl-1,3-bis(oxymethyl)imidazolidine-2,4-dione to aniline compound is x, wherein 0

[0039] According to an embodiment of the present application, the molar ratio of 5,5-dimethyl-1,3-bis(oxymethyl)imidazolidine-2,4-dione to aniline compound is x, 1

[0040] According to an embodiment of the present application, the molar ratio of 5,5-dimethyl-1,3-bis(oxymethyl)imidazolidine-2,4-dione to aniline compound is x, 1

[0041] According to an embodiment of the present application, the molar ratio of the 5,5-dimethyl-1,3-bis(oxymethylene methyl)imidazolidine-2,4-dione and the aniline compound is x, preferably, x=3 / 2.

[0042] According to an embodiment of the present application, the heating comprises three steps, heating at 50-60℃ first, heating at 100-110℃ second, and heating at 120-130℃ third. The pre-heating at 50-60℃ and the two-step high-temperature reaction to promote cross-linking reaction are adopted in the present application, and by limiting the three-step heating, the structure of XA1 or XA2 is generated, which guarantees the unique cross-linking structure of the aniline polymer of the present application and endows the aniline polymer of the present application with the property of high-voltage resistance.

[0043] According to an embodiment of the present application, the heating comprises three steps, preferably, heating at 50℃ first, heating at 100℃ second, and heating at 120℃ third.

[0044] According to an embodiment of the present application, the heating comprises three steps, heating the solution containing 5,5-dimethyl-1,3-bis(oxymethylene methyl)imidazolidine-2,4-dione, aniline compound and solvent at 50-60℃ first, then placing the solution on a heating plate, heating at 100-110℃ second, and heating at 120-130℃ third.

[0045] According to an embodiment of the present application, the heating comprises three steps, the first step of heating is for 5-6h, and the total time of the second and third steps of heating is 2-3h.

[0046] According to an embodiment of the present application, the heating comprises three steps, preferably, the first step of heating is for 5h, and the total time of the second and third steps of heating is 2h.

[0047] Another aspect of the present application also provides a positive electrode material. The raw material of the positive electrode material comprises the aniline polymer as described in the above-mentioned embodiment of the first aspect. Since all the technical solutions of the above-mentioned aniline polymer are adopted in this application, at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiment are possessed.

[0048] Another aspect of the present application also provides a battery, which comprises the positive electrode material, i.e. also comprises the aniline polymer as described in the above-mentioned embodiment of the first aspect.

[0049] According to an embodiment of the present application, the battery further comprises a negative electrode.

[0050] According to an embodiment of the present application, the negative electrode comprises one of metal lithium and graphite.

[0051] According to one embodiment of the present application, the lithium battery prepared by using the aniline-based polymer of the present application as the positive electrode material has a specific capacity of 118 mAh / g, and has a high specific capacity and coulombic efficiency after 600 cycles, and has excellent performance.

[0052] Other features and advantages of the present application will be set forth in the description that follows, and in part will become apparent to those skilled in the art upon examination of the following or can be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0053] The foregoing and / or additional aspects and advantages of the present application are achieved by providing what is described below and / or claimed by the appended claims, where:

[0054] Figure 1 Flow chart of the preparation method of the aniline-based polymer in Example 1.

[0055] Figure 2 Schematic diagram of the assembly structure of the lithium battery in Example 1.

[0056] Figure 3 Flow chart of the preparation method of the aniline-based polymer in Example 2.

[0057] Figure 4 Infrared spectrum of the aniline-based polymer obtained in Example 1.

[0058] Figure 5 Infrared spectrum of the aniline-based polymer obtained in Example 2.

[0059] Figure 6 Charge-discharge performance curve of the lithium battery prepared in Example 1.

[0060] Figure 7 Stability curve of the lithium battery prepared in Example 1.

[0061] Figure 8 Charge-discharge performance curve of the lithium battery prepared in Comparative Example. DETAILED DESCRIPTION

[0062] The words "preferred" and "preferably" in the present application refer to embodiments of the present application that can provide certain benefits under certain circumstances. However, other embodiments can also be preferred, or preferred under the same or other circumstances. Additionally, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude those other embodiments from the scope of the present application.

[0063] When a numerical range is disclosed herein, the range is to be construed as having a minimum value and a maximum value, and including each and every value between the minimum and maximum values. Further, when a range is stated to include integers, the range includes each and every integer between the minimum and maximum values. In addition, when a plurality of ranges are provided to describe a characteristic or a property, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood to include any and all sub-ranges subsumed therein.

[0064] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of the present application.

[0065] The reagents, methods and devices used in the present application are conventional reagents, methods and devices in the technical field unless otherwise specified.

[0066] In the examples and comparative examples, the 5,5-dimethyl-1,3-bis(oxymethylene methyl)imidazolidine-2,4-dione used has a CAS number of 15336-81-9.

[0067] In the description of the present application, the meaning of "about" is plus or minus 3% unless otherwise specified.

[0068] Example 1

[0069] An aniline polymer has a structural formula of:

[0070]

[0071] A method for preparing the above aniline polymer has a flow chart as shown in Figure 1 The method includes the following steps:

[0072] 3 mmol of 5,5-dimethyl-1,3-bis(oxymethylene methyl)imidazolidine-2,4-dione, 2 mmol of benzene-1,3,5-triamine and 2 ml of N-methylpyrrolidone are mixed to obtain a solution, the solution is stirred and heated at 50°C; after stirring for 5 h, the above solution is cast on a polytetrafluoroethylene plate and heated in a heating plate at 100°C first and then at 120°C, for a total of about 2 h; the last purple-black solid sample is collected to obtain the aniline polymer.

[0073] A battery includes a positive electrode, and a raw material of the positive electrode includes the above aniline polymer.

[0074] A method for preparing the above battery includes the following steps:

[0075] 1) Preparation of electrode sheet

[0076] The aniline-based polymer XA1, carbon black and polyvinylidene fluoride (PVDF) described above were weighed and mixed in a weight ratio of 6:3:1, and after grinding, the electrode sheet based on the cross-linked aniline-based polymer XA1 was obtained by tabletting, and after drying in a vacuum oven at 60°C for 8 hours, it was ready for use.

[0077] 2) Assembly of lithium battery

[0078] In an argon glove box, the cross-linked aniline-based polymer XA1 electrode sheet prepared above, a separator (with 0.1 ml of electrolyte added to the separator) and a lithium sheet were sequentially assembled according to the structure shown in Figure 2 , and after pressure packaging, the preparation of the battery was completed.

[0079] Example 2

[0080] The difference between Example 2 and Example 1 is that the aniline-based compound selected in the preparation of the aniline-based polymer in Example 2 is different from that in Example 1, so that the product aniline-based polymer structure of Example 2 is different from that of Example 1.

[0081] Specifically:

[0082] An aniline-based polymer, the structure of which is:

[0083]

[0084] The method for preparing the aniline-based polymer described above, the flow chart is shown in Figure 3 , which comprises the following steps:

[0085] 3 mmol of 5,5-dimethyl-1,3-bis(oxymethylene methyl) imidazolidine-2,4-dione, 2 mmol of tris(4-aminophenyl)amine and 2 ml of N-methyl pyrrolidone were mixed to obtain a solution, the solution was stirred and heated at 50°C; after stirring for 5 h, the above solution was poured onto a polytetrafluoroethylene plate, and heated in a heating plate first at 100°C and then at 120°C, for a total of about 2 h; the last purple-black solid sample was collected to obtain the aniline-based polymer.

[0086] A battery comprising a positive electrode, the raw material of the positive electrode comprising the aniline-based polymer described above.

[0087] The method for preparing the battery described above comprises the following steps:

[0088] 1) Preparation of electrode sheet

[0089] The aniline-based polymer XA2, carbon black and polyvinylidene fluoride (PVDF) above are weighed and mixed in a weight ratio of 6:3:1, and after grinding, the electrode sheet based on the crosslinked aniline-based polymer XA2 is obtained by tabletting, and after drying in a vacuum oven at 60°C for 8 hours, it is ready for use.

[0090] 2) Assembly of lithium battery

[0091] In an argon glove box, the electrode sheet of the crosslinked aniline-based polymer XA2 prepared above, a separator (with 0.1 ml of electrolyte added on the separator) and a lithium sheet are sequentially assembled according to the structure shown in Figure 2 , and after pressure packaging, the preparation of the battery is completed.

[0092] Comparative Example

[0093] The difference between the comparative example and Example 1 is that the comparative example uses 5,5-dimethyl-1,3-bis(oxymethylene methyl)imidazolidine-2,4-dione to directly prepare the electrode sheet.

[0094] Specifically:

[0095] A battery comprising a positive electrode, the raw material of the positive electrode comprising 5,5-dimethyl-1,3-bis(oxymethylene methyl)imidazolidine-2,4-dione.

[0096] A method for preparing the above battery, comprising the following steps:

[0097] (1) Preparation of electrode sheet

[0098] 5,5-dimethyl-1,3-bis(oxymethylene methyl)imidazolidine-2,4-dione, carbon black and polyvinylidene fluoride (PVDF) are weighed and mixed in a weight ratio of 6:3:1, and after grinding, the electrode sheet is obtained by tabletting, and after drying in a vacuum oven at 60°C for 8 hours, it is ready for use.

[0099] (2) Assembly of lithium battery

[0100] In an argon glove box, the electrode sheet of (5,5-dimethyl-1,3-bis(oxymethylene methyl)imidazolidine-2,4-dione) prepared above, a separator (with 0.1 ml of electrolyte added on the separator) and a lithium sheet are sequentially assembled according to the structure shown in Figure 2 , and after pressure packaging, the preparation of the battery is completed.

[0101] Performance test:

[0102] The structure of the aniline-based polymer obtained in Example 1 is determined by infrared spectroscopy experiment, and the results are shown in Figure 4 . From Figure 4As can be seen from the infrared characteristic peaks, the aniline characteristic functional groups in the polymer obtained by the reaction were successfully synthesized, and the epoxy functional groups underwent ring opening to generate the corresponding polyhydroxy products, that is, the cross-linked aniline polymer XA1 was successfully prepared.

[0103] The structure of the aniline polymer obtained in Example 2 was determined by infrared spectroscopy, and the results are as follows: Figure 5 As shown. From Figure 5 As can be seen from the infrared characteristic peaks, the aniline characteristic functional groups in the polymer obtained by the reaction were successfully synthesized, and the epoxy functional groups underwent ring opening to generate the corresponding polyhydroxy products, that is, the cross-linked aniline polymer XA2 was successfully prepared.

[0104] In the Blue Battery Testing System, the lithium battery prepared in Example 1 was tested for charge-discharge curves at 25°C with a current density of 50 mA / g. The resulting charge-discharge performance curves and lithium battery stability curves were obtained.

[0105] in, Figure 6 The graph shows the charge-discharge performance of the lithium battery prepared in Example 1. Figure 6 It can be seen that the lithium battery based on cross-linked aniline polymer XA1 prepared in Example 1 has a specific capacity of 118 mAh / g and an operating voltage range of 2.0 to 4.5 V, which meets the requirements of high-voltage batteries.

[0106] in, Figure 7 The image shows the stability curves of the lithium battery prepared in Example 1. Figure 7 It can be seen that the lithium battery assembled with the cross-linked aniline polymer XA1 prepared in Example 1 exhibits good stability, maintaining excellent capacity and coulombic efficiency after 600 cycles, meeting the requirements of high-voltage, high-stability batteries. Therefore, it can be seen that the aniline polymer of this invention is a class of high-performance lithium battery electrode materials.

[0107] In the Blue Battery testing system, the charge-discharge curves of the lithium battery prepared in the comparative example were tested at 25°C with a current density of 50 mA / g. The test results are as follows. Figure 8 Where voltage is the voltage and specific capacity is the specific capacity. From Figure 8 It is understood that using 5,5-dimethyl-1,3-di(epoxyethylenemethyl)imidazolidine-2,4-dione directly as the positive electrode material does not possess high voltage properties and does not meet the requirements of high-voltage batteries.

[0108] The above are merely embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An aniline polymer, characterized in that: The structural formula is as follows: ； Where A is selected from or ; Among them, R 1~6 Any three of them are And it is chemically bonded to -N in the structural formula, while the remaining R... 1~6 It is at least one of -H, -NH2, -CH3, and aromatic amines; Among them, R 7~21 Any three of them are And it is chemically bonded to -N in the structural formula, while the remaining R... 7~21 It is at least one of -H, -NH2, -CH3, and aromatic amines.

2. The aniline polymer according to claim 1, characterized in that: The R 7~21 Any three of them are And it is chemically bonded to -N in the structural formula, while the remaining R... 7~21 It is at least one of -H, -NH2, and -CH3.

3. The aniline polymer according to claim 1, characterized in that: The said structural formula is: or .

4. A method for preparing an aniline polymer as described in any one of claims 1 to 3, characterized in that: It includes the following steps: Mix 5,5-dimethyl-1,3-bis(oxiranylmethyl)imidazolidine-2,4-dione with an aniline compound in a solvent, and obtain the said aniline polymer through heating and crosslinking reactions.

5. The method according to claim 4, characterized in that: The molar ratio of the said 5,5-dimethyl-1,3-bis(oxiranylmethyl)imidazolidine-2,4-dione to the aniline compound is x, where 0 < x < 1000 and x is a real number.

6. The method according to claim 4, characterized in that: The said heating includes three-step heating. First, heat at 50 - 60 °C, then heat at 100 - 110 °C, and finally heat at 120 - 130 °C.

7. A positive electrode material, characterized in that: The raw material of the said positive electrode material contains an aniline polymer as described in any one of claims 1 to 3.

Images