An organic bipolar electrode material, a preparation method and application thereof

Abstract

The application relates to the technical field of batteries, and discloses an organic bipolar electrode material and a preparation method and application thereof, the structural formula of the organic bipolar small-molecule electrode material is shown in the following formula: named as DQPZ-3PXZ; the preparation method is as follows: an intermediate product is obtained by reacting 4-bromobenzene-1,2-diamine and cyclohexanhexanone octahydrate, then the intermediate product is reacted with phenoxazine to prepare the organic bipolar small-molecule electrode material DQPZ-3PXZ. Through the design and synthesis of organic molecules and the control of the reaction, a high-performance organic bipolar small-molecule electrode material with a p-n structure is obtained, the organic bipolar small-molecule electrode material has the characteristics of insolubility, can be used as the only electrode material to construct various double-ion symmetrical batteries, has high capacity, high potential and high stability, can make the battery have very excellent energy density, cycle life and cycle stability, and greatly improves the application range of the organic electrode material, and can meet the large-scale and low-cost battery energy storage demand.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to an organic bipolar electrode material, a preparation method thereof and application thereof in alkali metal ion batteries. BACKGROUND

[0002] At present, the inorganic positive electrode materials used in commercialized lithium ion batteries are mostly oxides containing transition metals (such as cobalt), which are high in cost, pollute the environment and are difficult to meet the demand of large-scale and low-cost battery energy storage. Therefore, it is urgent to develop new lithium ion battery positive electrode materials with low cost.

[0003] Compared with inorganic electrode materials, organic electrode materials have many unique advantages, such as flexibility, low cost, ecological friendliness, designability of molecular structure, and better electrochemical performance. At the same time, due to the more loose solid lattice of organic materials, organic electrode materials can more efficiently and stably store lithium ions and other metal cations compared with inorganic materials.

[0004] At present, most of the organic positive electrode materials reported in lithium ion batteries are n-type materials, and their redox potentials are usually below 3V (vs. Li). On the contrary, there are few reports on organic p-type positive electrode materials with high redox potential (>3V) in lithium ion batteries. In addition, there are very few studies on using a single organic electrode material as both positive and negative electrode materials (referred to as bipolar material) to construct a symmetric battery, and the cycle stability of the constructed symmetric battery is very poor.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] The existing problems of the prior art are that there are very few studies on using traditional lithium ion organic electrode materials as both positive and negative electrode materials to construct a symmetric battery, and the cycle stability of the constructed symmetric battery is very poor. The purpose of the present application is to provide an organic bipolar electrode material, a preparation method thereof and application thereof. Through the design and synthesis of organic molecules and the control of the reaction, a high-performance organic bipolar small-molecule electrode material with p-n structure is obtained. The n-type part can store alkali metal ions, and the p-type part can store anions in the electrolyte, which has the characteristic of not dissolving. The material is used as the only electrode material in various double-ion symmetric batteries, which can make the battery have very excellent energy density, cycle life and cycle stability.

[0007] The present application is realized by the following technical scheme:

[0008] In one aspect, the present application provides an organic bipolar small-molecule electrode material with p-n structure, and the structural formula of the organic bipolar small-molecule electrode material is as follows:

[0009] For the convenience of description, it is named as DQPZ-3PXZ.

[0010] The application obtains a high-performance organic bipolar small-molecule electrode material with p-n structure by designing and synthesizing organic molecules. The n-type part of the material can store alkali metal ions, the p-type part can store anions in electrolyte, and the material has the characteristic of insolubility. When the material is used as the only electrode material in various double-ion symmetric batteries, the batteries can have excellent energy density, cycle life and cycle stability.

[0011] The application can be used as the only electrode material in lithium / sodium / potassium double-ion symmetric batteries, that is, an organic bipolar electrode material can be used to construct three kinds of alkali metal double-ion symmetric batteries, greatly improving the application range of the organic electrode material and meeting the large-scale and low-cost battery energy storage needs.

[0012] In the second aspect, the application further provides a preparation method of the organic bipolar small-molecule electrode material. An intermediate product is obtained by reacting 4-bromobenzene-1,2-diamine and cyclohexanehexaketone octahydrate, and then the intermediate product is reacted with phenoxazine to obtain the organic bipolar small-molecule electrode material DQPZ-3PXZ. The reaction formula is shown below:

[0013]

[0014] In a specific embodiment, the specific steps of the preparation method include:

[0015] (1) 4-bromobenzene-1,2-diamine and cyclohexanehexaketone octahydrate are mixed in an organic solvent I, and DQPZ-3Br is prepared by reacting at 120-130℃ under an inert atmosphere.

[0016] (2) After phenoxazine, DQPZ-3Br, X-Phos, sodium tert-butoxide and Pd2(dba)3 are mixed, organic solvent II is added under an inert atmosphere, and DQPZ-3PXZ is prepared by reacting at 100-120℃.

[0017] In a specific embodiment, the organic solvent I includes one or both of glacial acetic acid and ethanol; and the organic solvent II includes toluene, xylene or 1,4-dioxane.

[0018] In the third aspect, the application further provides an application of the organic bipolar small-molecule electrode material. The application of the organic bipolar small-molecule electrode material or the organic bipolar small-molecule electrode material prepared by the preparation method of the organic bipolar small-molecule electrode material in an alkali metal ion battery.

[0019] In a specific embodiment, the alkali metal ions include lithium ions, sodium ions, or potassium ions.

[0020] In a specific embodiment, the alkali metal ion battery is an alkali metal dual-ion symmetric battery.

[0021] In a fourth aspect, the present application further provides an electrode sheet, which simultaneously serves as a positive electrode sheet and a negative electrode sheet.

[0022] The positive electrode sheet comprises an organic positive electrode material, which is the organic bipolar small-molecule electrode material described above or the organic bipolar small-molecule electrode material prepared by the preparation method of the organic bipolar small-molecule electrode material described above.

[0023] The negative electrode sheet comprises an organic negative electrode material, which is the organic bipolar small-molecule electrode material described above or the organic bipolar small-molecule electrode material prepared by the preparation method of the organic bipolar small-molecule electrode material described above.

[0024] In a fifth aspect, the present application further provides a preparation method of an electrode sheet, which comprises mixing the organic bipolar small-molecule electrode material described above or the organic bipolar small-molecule electrode material prepared by the preparation method of the organic bipolar small-molecule electrode material described above with a conductive agent, a binder, and a solvent to form a slurry, and then coating the slurry on an aluminum foil to obtain the electrode sheet after drying.

[0025] In a sixth aspect, the present application further provides one or more alkali metal dual-ion symmetric batteries, wherein the positive electrode material of the battery comprises the organic bipolar small-molecule electrode material described above or the organic bipolar small-molecule electrode material prepared by the preparation method of the organic bipolar small-molecule electrode material described above; and / or the negative electrode material of the battery comprises the organic bipolar small-molecule electrode material described above or the organic bipolar small-molecule electrode material prepared by the preparation method of the organic bipolar small-molecule electrode material described above; or the positive electrode sheet and / or the negative electrode sheet of the battery comprises the electrode sheet described above.

[0026] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0027] 1. The organic bipolar electrode material provided by the embodiment of the present application, the preparation method and application thereof, through the design and synthesis of organic molecules and the control of the reaction, a high-performance organic bipolar small-molecule electrode material with p-n structure is obtained, the n-type part of the material can store alkali metal ions, the p-type part can store anions in the electrolyte, and the material has the characteristic of insolubility, the material is used as the only electrode material in various double-ion symmetric batteries, has high capacity, high potential and high stability, and can make the battery have very excellent energy density, cycle life and cycle stability.

[0028] 2. The organic bipolar electrode material provided by the embodiment of the present application, the preparation method and application thereof, can be used as the only electrode material in lithium / sodium / potassium double-ion symmetric batteries, that is, an organic bipolar electrode material can be used to construct three kinds of alkali metal double-ion symmetric batteries, greatly improving the application range of the organic electrode material, and meeting the large-scale and low-cost battery energy storage demand. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below, and it should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and other related drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0030] Figure 1 The organic synthesis route of the embodiment DQPZ-3PXZ of the present application;

[0031] Figure 2 The (a) hydrogen spectrum nuclear magnetic resonance diagram and (b) mass spectrum of the embodiment DQPZ-3PXZ of the present application;

[0032] Figure 3 The electrochemical performance diagram of the embodiment DQPZ-3PXZ of the present application in lithium (Li) double-ion symmetric batteries: (a) small current charge-discharge curve diagram; (b) small current long cycle stability diagram;

[0033] Figure 4 The electrochemical performance diagram of the embodiment DQPZ-3PXZ of the present application in sodium (Na) double-ion symmetric batteries: (a) small current charge-discharge curve diagram; (b) small current long cycle stability diagram;

[0034] Figure 5 The electrochemical performance diagram of the embodiment DQPZ-3PXZ of the present application in potassium (K) double-ion symmetric batteries: (a) small current charge-discharge curve diagram; (b) small current long cycle stability diagram. DETAILED DESCRIPTION

[0035] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with embodiments and drawings. The schematic embodiments of the present application and the descriptions thereof are only used to explain the present application and do not limit the present application.

[0036] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one ordinarily skilled in the art that the present application can be practiced without these specific details. In other instances, well-known structures, circuits, materials or processes have not been described in detail in order to avoid obscuring the present application.

[0037] Throughout the specification, reference to "one embodiment", "an embodiment", "one example" or "an example" means that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present application. Therefore, the appearance of the phrases "in one embodiment", "in an embodiment", "in one example" or "in an example" in various places throughout the specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics can be combined in any suitable

[0038] In the description of the present application, the terms "front", "back", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the scope of protection of the present application.

[0039] Embodiment 1

[0040] As shown in Figure 1 The preparation method of the organic bipolar electrode material DQPZ-3PXZ provided by the embodiment of the present application comprises the following steps:

[0041] 4-bromophenyl-1,2-diamine (1.41 g, 7.53 mmol), cyclohexanehexaketone octahydrate (0.783 g, 2.51 mmol) were added into a 250 ml two-necked flask. At the same time, 50 ml of glacial acetic acid was added. The mixture was stirred at 125 °C for 24 h. Then the mixture was filtered, the precipitate was washed with water, ethanol and acetone for several times, and then dried in an oven at 100 °C overnight. Finally, DQPZ-3Br yellow-green solid was obtained with a yield of more than 90%.

[0042] Subsequently, phenoxazine (0.906 g, 4.95 mmol), DQPZ-3Br (0.927 g, 1.5 mmol), X-Phos (257.2 mg, 54 mmol), sodium tert-butoxide (475.2 mg, 4.95 mmol) and Pd2(dba)3(135 mg, 13.5 mmol) were added into 45 mL of toluene under N2atmosphere. The mixture was reacted at 110 °C for 3 days. After cooling to room temperature, the solid was directly washed with water and ethanol for three times. Then it was dried at 100 °C to obtain 1.11 g of blue-black solid. The obtained product was detected by nuclear magnetic hydrogen spectrum and mass spectrum as shown in Figure 2 , and it can be seen from the figure that the obtained product is DQPZ-3PXZ.

[0043] Example 2

[0044] As shown in Figure 1 , the preparation method of the organic bipolar electrode material DQPZ-3PXZ provided by the embodiment of the application comprises the following steps:

[0045] As shown in Figure 1 , 4-bromophenyl-1,2-diamine (1.41 g, 7.53 mmol), cyclohexanehexaketone octahydrate (0.783 g, 2.51 mmol) were added into a 250 ml two-necked flask. At the same time, 50 ml of glacial acetic acid was added. The mixture was stirred at 125 °C for 24 h. Then the mixture was filtered, the precipitate was washed with water, ethanol and acetone for several times, and then dried in an oven at 100 °C overnight. Finally, DQPZ-3Br yellow-green solid was obtained with a yield of more than 90%.

[0046] Subsequently, phenoxazine (0.906 g, 4.95 mmol), DQPZ-3Br (0.927 g, 1.5 mmol), X-Phos (257.2 mg, 54 mmol), sodium tert-butoxide (475.2 mg, 4.95 mmol), and Pd2(dba)3(135 mg, 13.5 mmol) were added, followed by 45 mL of 1,4-dioxane under N2atmosphere. The mixture was reacted at 110 °C for 3 days. After cooling to room temperature, the solid was directly washed with water and ethanol three times. Then it was dried at 100 °C to obtain 1.11 g of DQPZ-3PXZ blue-black solid.

[0047] Example 3

[0048] As shown in Figure 1 The preparation method of the organic bipolar electrode material DQPZ-3PXZ provided by the embodiment of the application comprises the following steps:

[0049] As shown in Figure 1 4-bromobenzene-1,2-diamine (1.41 g, 7.53 mmol) and cyclohexanehexaketone octahydrate (0.783 g, 2.51 mmol) were added into a 250 mL two-necked flask. At the same time, 50 mL of ethanol was added. The mixture was stirred at 125 °C for 24 h. Then the mixture was filtered, and the precipitate was washed with water, ethanol and acetone several times, and then dried in an oven at 100 °C overnight. Finally, more than 90% of DQPZ-3Br yellow-green solid was obtained.

[0050] Subsequently, phenoxazine (0.906 g, 4.95 mmol), DQPZ-3Br (0.927 g, 1.5 mmol), X-Phos (257.2 mg, 54 mmol), sodium tert-butoxide (475.2 mg, 4.95 mmol), and Pd2(dba)3(135 mg, 13.5 mmol) were added, followed by 45 mL of 1,4-dioxane under N2atmosphere. The mixture was reacted at 110 °C for 3 days. After cooling to room temperature, the solid was directly washed with water and ethanol three times. Then it was dried at 100 °C to obtain 1.11 g of DQPZ-3PXZ blue-black solid.

[0051] Example 4

[0052] The preparation method of the DQPZ-3PXZ electrode sheet provided by the embodiment of the application comprises the following steps:

[0053] First, the DQPZ-3PXZ (60 wt%) prepared in Example 1, Ketjen black (30 wt%), and polyacrylonitrile copolymer (10 wt%) were mixed, and then uniformly coated on an aluminum foil. The loading mass of DQPZ-3PXZ on the electrode sheet is greater than 2 mg cm -2, pressed into a round aluminum electrode sheet.

[0054] The single electrode sheet is applied to a lithium / sodium / potassium dual-ion symmetric battery as a positive electrode sheet and a negative electrode sheet respectively, and the redox potential, actual specific capacity and cycle stability are tested.

[0055] Example 5

[0056] The preparation method of the lithium dual-ion symmetric battery provided by the embodiment of the application comprises the following steps:

[0057] The unactivated DQPZ-3PXZ electrode sheet prepared in Example 4 is used as a positive electrode and a negative electrode, 3M LiFSI+TEGDME is used as an electrolyte to assemble a lithium dual-ion symmetric battery, and the electrochemical performance of the lithium dual-ion symmetric battery is tested.

[0058] It can be seen from Figure 3 that the median voltage of the lithium dual-ion symmetric battery is about 1.36V, and the stable specific capacity can reach 85mAh g -1 . Therefore, based on the calculation of the positive electrode material, the lithium dual-ion symmetric battery can achieve a high energy density of 116Wh kg -1 . Under a large current of 2Ag -1 , the discharge specific capacity can be stabilized at 73mAh g -1 after 15000 cycles of long cycle, and the capacity retention rate is about 100%.

[0059] Example 6

[0060] The preparation method of the sodium dual-ion symmetric battery provided by the embodiment of the application comprises the following steps:

[0061] The unactivated DQPZ-3PXZ electrode sheet prepared in Example 4 is used as a positive electrode and a negative electrode, 1.5M NaFSI+TEGDME is used as an electrolyte to assemble a sodium dual-ion symmetric battery, and the electrochemical performance of the sodium dual-ion symmetric battery is tested.

[0062] It can be seen from Figure 4 that the median voltage of the sodium dual-ion symmetric battery is about 1.34V, and the stable specific capacity can reach 66mAh g -1 . Therefore, based on the calculation of the positive electrode material, the sodium dual-ion symmetric battery can achieve a high energy density of 88Wh kg -1 . Under a large current of 2Ag -1 , the discharge specific capacity can be stabilized at 56mAh g -1 after 40000 cycles of long cycle, and the capacity retention rate is about 98%.

[0063] Example 7

[0064] The embodiment of the present application provides a preparation method of a potassium dual-ion symmetrical battery, and comprises the following steps:

[0065] The unactivated DQPZ-3PXZ electrode sheet prepared in the embodiment 4 is used as a positive electrode and a negative electrode, 3M KFSI+TEGDME is used as an electrolyte to assemble a potassium dual-ion symmetrical battery, and the electrochemical performance of the battery is tested.

[0066] From Figure 5 It can be seen that the median voltage of the full battery is about 1.43V, and the stable specific capacity can reach 72mAh g -1 Therefore, based on the positive electrode material, the symmetrical battery can achieve a high energy density of 103Wh kg -1 Under the current of 2Ag -1 , the discharge specific capacity can be stabilized at 60mAh g -1 after 40000 cycles, and the capacity retention rate is about 97%.

[0067] Through the performance test of the lithium, sodium and potassium dual-ion symmetrical batteries, it is proved that the DQPZ-3PXZ is a new type of organic bipolar small molecule electrode material with high capacity, high potential and high stability in lithium / sodium / potassium dual-ion symmetrical batteries, and when the DQPZ-3PXZ is used as the only electrode material in the lithium / sodium / potassium dual-ion symmetrical batteries, excellent energy density, cycle life and cycle stability can be obtained.

[0068] The organic bipolar electrode material can be used to construct three kinds of alkali metal dual-ion symmetrical batteries, greatly improves the application range of the organic electrode material, and can meet the large-scale and low-cost battery energy storage demand.

[0069] The above specific embodiments further specifically describe the purposes, technical solutions and beneficial effects of the present application, and it should be understood that the above description is only a specific embodiment of the present application, and is not used to limit the protection scope of the present application, and any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. Use of an organic bipolar small-molecule electrode material having a p-n structure, characterized in that, A method for preparing a positive electrode and a negative electrode of an alkali metal dual-ion symmetrical battery simultaneously as the only electrode material The structure of the organic bipolar small-molecule electrode material is shown as follows: ; designated DQPZ-3PXZ.

2. The use of an organic bipolar small-molecule electrode material according to claim 1, characterized in that, The alkali metal ions include lithium ions, sodium ions or potassium ions.

3. A method for preparing an organic bipolar small-molecule electrode material, characterized by, The organic bipolar small-molecule electrode material DQPZ-3PXZ is prepared by reacting 4-bromobenzene-1,2-diamine and cyclohexanehexaketone octahydrate to obtain an intermediate, and then reacting the intermediate with phenoxazine, and the reaction formula is shown as follows: 。 4. The method of claim 3, wherein the organic bipolar small-molecule electrode material is prepared by the steps of: (a) preparing a solution of the organic bipolar small-molecule electrode material in a solvent; (b) coating the solution on a substrate; and (c) drying the coated solution. The specific steps include: (1) mixing 4-bromobenzene-1,2-diamine and cyclohexanehexaketone octahydrate in an organic solvent I, and reacting at 120-130°C under an inert atmosphere to obtain DQPZ-3Br; (2) mixing phenoxazine, DQPZ-3Br, X-Phos, sodium tert-butoxide and Pd2(dba)3, then adding an organic solvent II under an inert atmosphere, and reacting at 100-120°C to obtain DQPZ-3PXZ.

5. The method for preparing the organic bipolar small molecule electrode material according to claim 4, characterized in that, The organic solvent I includes one or both of glacial acetic acid and ethanol; and the organic solvent II includes toluene, xylene or 1,4-dioxane.

6. An electrode sheet characterized by The electrode sheet simultaneously serves as a positive electrode sheet and a negative electrode sheet; The positive electrode sheet includes an organic positive electrode material, and the organic positive electrode material is the organic bipolar small-molecule electrode material of claim 1 or the organic bipolar small-molecule electrode material prepared by the preparation method of any one of claims 3-5; The negative electrode sheet includes an organic negative electrode material, and the organic negative electrode material is the organic bipolar small-molecule electrode material of claim 1 or the organic bipolar small-molecule electrode material prepared by the preparation method of any one of claims 3-5.

7. A method of producing an electrode sheet, characterized by The organic bipolar small-molecule electrode material of claim 1 or the organic bipolar small-molecule electrode material prepared by the preparation method of any one of claims 3-5 is mixed with a conductive agent, a binder and a solvent to form a slurry, and then the slurry is coated on an aluminum foil to obtain the electrode sheet after drying.

8. One or more pairs of alkali metal di-ion symmetric cells characterized in that, The battery positive electrode material includes the organic bipolar small-molecule electrode material of claim 1 or the organic bipolar small-molecule electrode material prepared by the preparation method of any one of claims 3-5; and / or the battery negative electrode material includes the organic bipolar small-molecule electrode material of claim 1 or the organic bipolar small-molecule electrode material prepared by the preparation method of any one of claims 3-5; or the positive electrode sheet and / or the negative electrode sheet of the battery includes the electrode sheet prepared by claim 7.

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