Preparation method of aqueous organic negative electrode active material and aqueous organic negative electrode and aqueous battery

Abstract

The application discloses a preparation method of water-based organic negative electrode active material, a water-based organic negative electrode and a water-based battery, and optimizes the synthesis process of the HATNQ material, and meanwhile, a conductive material is added in the synthesis process of the material, so that the material can grow in the micropores or mesopores of the conductive material in the synthesis process, and the composite uniformity of the material is promoted. Meanwhile, the electrochemical performance of the HATNQ material is more excellent, and on this basis, the water-based battery composed of the material and a commercial sintered nickel positive electrode has a wide raw material source and low price, and can effectively solve the problem of high price of the existing water-based battery.

Description

Technical Field

[0001] This invention belongs to the technical field of aqueous organic anode materials, specifically relating to a method for preparing an aqueous organic anode active material, an aqueous organic anode, and an aqueous battery. Background Technology

[0002] The increasing demand for grid energy storage, driven by the emergence of intermittently available renewable energy sources and the destructive consequences of global warming and climate change, has led to an exponential increase in research into alternative and sustainable battery technologies. While transition metal-based inorganic compounds are primarily used as cathodes in lithium-ion batteries, the development of organic anode materials continues to accelerate. Compared to inorganic compounds, organic compounds are considered more environmentally friendly, as they are composed of naturally abundant elements (C, H, N, O, and S), eliminating the need for expensive and toxic metals and allowing for direct synthesis from renewable resources or existing small molecules. Therefore, organic electrode materials can reduce energy consumption and CO2 emissions during large-scale production processes.

[0003] Small-molecule organic compounds can be precisely designed and synthesized, resulting in molecules containing well-defined redox-active functional groups. Due to this unparalleled chemical and structural tunability, a large number of redox-active sites can be designed into a single molecule. The redox potential of organic electrode materials can be increased or decreased by introducing electron-withdrawing and electron-donating groups into conjugated structures, thus allowing for fine-tuning of organic molecules at the molecular level. Therefore, organic compounds are used as electrode materials in batteries due to the relative flexibility of their structures, the rapid reaction kinetics they offer, and their ease of handling.

[0004] Although an increasing number of organic molecules have been developed and applied to battery systems, most organic electrode materials suffer from low conductivity and solubility, leading to poor cycle performance, rapid capacity decay, and low coulombic efficiency. While various methods have been developed to address these issues, such as polymerization, immobilizing active materials onto other conductive materials (carbon nanotubes), and salt formation, these methods, while reducing solubility and improving electronic conductivity, increase the molecular weight of the active material, resulting in a decrease in energy density. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0007] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing an aqueous organic negative electrode active material.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: including,

[0009] The compound shown in formula (I) was dissolved in acetonitrile and then o-phenylenediamine was added. The mixture was stirred and refluxed under N2 atmosphere to obtain the compound shown in formula (II).

[0010] The compound shown in formula (II) was mixed with hydrazine hydrate, heated and stirred, cooled and filtered, and then recrystallized in ethanol to obtain the compound shown in formula (III).

[0011] The conductive agent Ketjen black was dispersed in an acetic acid solution, ultrasonically stirred, and cyclohexanehexanone octahydrate was added. After stirring, the mixture was allowed to stand under vacuum to obtain the reaction solution.

[0012] Under N2 atmosphere, the compound shown in formula (III) is added to the reaction solution, stirred and heated under reflux. After the reaction is completed, the product is cooled, filtered, washed and freeze-dried to obtain the aqueous organic anode material.

[0013]

[0014] In a preferred embodiment of the preparation method of the aqueous organic negative electrode active material of the present invention, the stirring and reflux time is 11-13 h; the heating temperature of the heating and reflux is 120-135 °C, and the time is 4.5-5.5 h.

[0015] As a preferred embodiment of the preparation method of the aqueous organic negative electrode active material of the present invention, the heating time of the compound represented by formula (II) mixed with hydrazine hydrate and stirred is 1.5 to 2.5 h, and the heating temperature is 55 to 65 °C.

[0016] In a preferred embodiment of the preparation method of the aqueous organic negative electrode active material of the present invention, the molar ratio of the octahydrate cyclohexanehexaone to the compound shown in formula (III) is 1:3 to 3.2.

[0017] Another object of the present invention is to provide an aqueous organic negative electrode active material with the structural formula shown in formula (IV);

[0018] Another object of the present invention is to provide an aqueous organic negative electrode.

[0019] To solve the above-mentioned technical problems, the present invention provides the following technical solution: including the aqueous organic negative electrode active material.

[0020] As a preferred embodiment of the aqueous organic anode of the present invention, the aqueous organic anode further includes polytetrafluoroethylene; wherein the mass ratio of polytetrafluoroethylene to the aqueous organic anode material is 0.5 to 1:9.

[0021] Another object of the present invention is to provide a method for preparing an aqueous organic negative electrode.

[0022] To solve the above-mentioned technical problems, the present invention provides the following technical solution: including,

[0023] Aqueous organic anode active material is mixed with polytetrafluoroethylene and then deionized water is added to obtain a precursor solution;

[0024] After grinding the precursor liquid, vacuum drying, mixing, and pressing are performed to obtain the aqueous organic anode.

[0025] Another object of the present invention is to provide an aqueous battery.

[0026] To solve the above-mentioned technical problems, the present invention provides the following technical solution: the aqueous battery is assembled using an aqueous organic negative electrode as the negative electrode, KOH as the electrolyte, and sintered nickel as the positive electrode.

[0027] Beneficial effects of this invention:

[0028] (1) This invention combines the advantages of quinone and azine materials, and designs a small molecule π-conjugated material (HATNQ) with multiple active centers based on azine materials. Because this material has abundant carbonyl and C=N groups, it can provide high theoretical capacity.

[0029] (2) This invention optimizes the synthesis process of HATNQ material and adds conductive materials during the synthesis process, enabling the material to grow in the micropores or mesopores of the conductive materials, thus promoting the uniformity of the composite material. This also improves the electrochemical performance of HATNQ material. Based on this, aqueous batteries constructed with this material and commercially available sintered nickel cathodes have a wide availability of raw materials and are inexpensive, effectively solving the problem of high prices in existing aqueous batteries. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0031] Figure 1The hydrogen spectrum of DANQ prepared in Example 1 of this invention is shown.

[0032] Figure 2 The hydrogen spectrum of DANQ prepared in Comparative Example 1 of this invention is shown.

[0033] Figure 3 The hydrogen spectrum of HATNQ prepared in Example 2 of this invention is shown.

[0034] Figure 4 This is a SEM image of HATNQ obtained in Example 2 of the present invention.

[0035] Figure 5 This is a cyclic voltammetry curve of the HATNQ three-electrode system obtained in Example 2 of the present invention.

[0036] Figure 6 This is a cyclic voltammetry curve of the full cell obtained in Example 2 of the present invention.

[0037] Figure 7 The cyclic voltammetry curve of the battery with a three-electrode system obtained in Example 2 of the present invention is shown.

[0038] Figure 8 This is a cyclic voltammetry curve of the full cell prepared in Comparative Example 2 of this invention.

[0039] Figure 9 This is a cyclic voltammetry curve of the full cell prepared in Comparative Example 3 of this invention. Detailed Implementation

[0040] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0041] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0042] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0043] Unless otherwise specified, all raw materials used in this invention are commercially available analytical grade materials commonly used in the field.

[0044] This invention evaluates the redox peak positions of the HATNQ organic anode material using a cyclic voltammetry method in a three-electrode system. The test conditions are as follows:

[0045] The electrolyte was 6M KOH 50ml. The prepared aqueous organic negative electrode was used as the working electrode, Hg / HgO was used as the reference electrode, and a graphite rod was used as the counter electrode. The three-electrode system was assembled.

[0046] Cyclic voltammetry tests were performed on the three-electrode system using a Nova electrochemical workstation. The voltage range was 0 to -1.1V, with discharge followed by charging, and a scan rate of 5mV / s.

[0047] This invention uses the Newwell battery tester to test the cycle performance of aqueous batteries. The test conditions are as follows:

[0048] Full battery:

[0049] After battery assembly, it was left to rest for 12 hours before charge-discharge testing. Charging was performed first, followed by discharging, with a voltage range of 1.5 to 0.5V and a current density of 0.2A / g. -1 The current is set according to the mass of HATNQ in the negative electrode, and the specific capacity of the aqueous battery is calculated based on the mass of HATNQ in the negative electrode.

[0050] Three-electrode battery:

[0051] Discharge first, then charge; voltage range: -1 to -0.01V; current density: 0.5A g. -1 The current is set according to the mass of the negative electrode HATNQ, and the specific capacity of the aqueous battery is calculated based on the mass of the negative electrode HATNQ.

[0052] Example 1

[0053] This embodiment provides a method for preparing 2,3-diamino-1,4-naphthoquinone (DANQ), a raw material used in the water-synthesized aqueous organic negative electrode active material HATNQ;

[0054] Refer to the reaction formula (V-1):

[0055]

[0056] Specifically:

[0057] 10 g (44 mmol) of dichlorocyanobenzoquinone (DCNQ, formula I) was dissolved in 200 ml of acetonitrile, and then 16.5 g (89.1 mmol) of potassium o-phenylenediamine was added. The reaction mixture was stirred and refluxed under N2 atmosphere for 12 h. After cooling to room temperature, the mixture was filtered to obtain a yellow solid (formula II), which was dried under vacuum.

[0058] The yellow solid was dissolved in a three-necked flask containing distilled water, 80 ml of 80% hydrazine hydrate was added, and the mixture was stirred at 60 °C for 2 h. After cooling and filtration, a dark blue powder was obtained, which was then purified by recrystallization in ethanol to obtain DANQ (Formula III).

[0059] Comparative Example 1

[0060] This comparative example cites the DANQ synthesis process mentioned in the literature "Supramolecular Self-Assembled Multi-Electron-Acceptor Organic Molecule as High-Performance Cathode Material for Li-IonBatteries". The stirring time in step 2) of Example 1 is adjusted to 6 hours, and the remaining process steps are the same as in the example to obtain the DANQ (Formula III) of this comparative example.

[0061] Figure 1 , Figure 2 The figures show the proton NMR spectra of DANQ prepared in Example 1 and Comparative Example 1, respectively. Figure 1 The spectrum for Example 1 with a reaction time of 2 hours corresponds to characteristic peaks of 5.46 ppm, 7.59 ppm, and 7.75 ppm. Figure 2 The spectrum for Comparative Example 1 with a reaction time of 6 hours corresponds to characteristic peaks of 5.45 ppm, 7.59 ppm, and 7.75 ppm. As can be seen from the comparison, the present invention successfully obtained DANQ even after significantly shortening the reaction time.

[0062] Example 2

[0063] This embodiment provides a method for preparing an aqueous battery, specifically as follows:

[0064] 1) Prepare aqueous organic anode active materials according to formula (V-2);

[0065]

[0066] Add 60 ml of acetic acid to a 250 ml three-necked flask, then add 50% (by mass) of KB, stir thoroughly for 1 h, and sonicate for 30 min to ensure that KB is evenly dispersed in acetic acid.

[0067] Add 0.624g of cyclohexanehexanone octahydrate and stir thoroughly until the reactants are completely dissolved. Keep the three-necked flask under vacuum for 4 hours to purge the air from the micropores / mesopores of KB and allow the reaction solution to fully wet the mixture.

[0068] Under N2 protection conditions, slowly add 1.22g DANQ, stir thoroughly until dissolved, and then heat under reflux at 130℃ for 5h;

[0069] After cooling, the filter cake was filtered, and then washed five times each with water, ethanol, and acetone to ensure thorough cleaning. The resulting filter cake was then freeze-dried for 48 hours until its mass no longer decreased, thus obtaining the aqueous organic negative electrode active material HATNQ.

[0070] Figure 3 The hydrogen spectrum of HATNQ obtained in this embodiment shows characteristic peaks of 8.87 ppm and 8.33 ppm, proving the successful synthesis of the product.

[0071] Figure 4 To obtain the SEM image of HATNQ, Figure 5 The cyclic voltammetry curves of HATNQ at 5 mV / s in a three-electrode system are shown. During discharge, HATNQ exhibits four reduction peaks: -1.0 V, -0.84 V, -0.63 V, and -0.225 V. During charging, four oxidation peaks are observed: -0.90 V, -0.76 V, -0.60 V, and -0.19 V. This indicates that the redox reaction of HATNQ proceeds stepwise and is highly reversible.

[0072] 2) Preparation of aqueous organic anode:

[0073] Step 1) The HATNQ obtained is mixed with polytetrafluoroethylene at a mass ratio of 9:1, deionized water is added, and the mixture is ground in an agate mortar for 40 minutes. The mixture is then placed in a vacuum drying oven at 40°C for 40 minutes. The material is then kneaded into a clay-like consistency and pressed into a thin sheet to obtain the water-based organic negative electrode.

[0074] Cut with scissors into 1*1cm pieces. 2 Small pieces of electrode material were pressed onto nickel foam at a pressure of 10 MPa and weighed. The mass of the electrode material and the mass of the active material were then calculated.

[0075] 3) Electrolyte preparation: Mix KOH with deionized water to prepare a 6M KOH electrolyte;

[0076] 4) Battery assembly:

[0077] A: Full battery:

[0078] Using the organic negative electrode material obtained in step 2) as the negative electrode, the 6M KOH obtained in step 3) as the electrolyte, PBI as the separator, and sintered nickel with a diameter of 10 mm as the positive electrode, a CR2032 button cell was assembled.

[0079] B: Three-electrode battery assembly:

[0080] Add 30 ml of 6 M KOH electrolyte to a 50 ml electrolytic cell. The organic negative electrode obtained in step 2) is the working electrode, Hg / HgO is the reference electrode, and the graphite rod is the counter electrode. Assemble the three electrodes.

[0081] Figure 6 The figures show the charge-discharge curves of the battery prepared in this embodiment at 0.2 A / g for the 1st, 5th, 15th, and 20th cycles. The reversible capacities at 0.5 A / g for the 1st, 5th, 10th, 15th, and 20th cycles are 359.35 mAh / g, 352.28 mAh / g, 347.24 mAh / g, 337.82 mAh / g, and 328.08 mAh / g, respectively.

[0082] Figure 7 The charge-discharge curves for the 1st, 5th, 15th, and 20th cycles under HATNQ at 0.5 A / g in a three-electrode system are shown. The reversible capacities for the 1st, 5th, 10th, 15th, and 20th cycles at 0.5 A / g are 529.92 mAh / g, 502.07 mAh / g, 492.62 mAh / g, 458.95 mAh / g, and 459.56 mAh / g, respectively.

[0083] Comparative Example 2

[0084] The difference between this comparative example and Example 2 is that the addition of the conductive agent Ketjen black in step 2) is adjusted, and DQPZ is generated first and then compounded with Ketjen black.

[0085] 1) Prepare aqueous organic anode active materials according to formula (II);

[0086] Add 60 ml of acetic acid and 0.624 g of cyclohexanehexanone octahydrate to a 250 ml three-necked flask, and stir thoroughly until the reactants are completely dissolved.

[0087] Introduce N2, slowly add 1.22g DANQ, stir thoroughly until dissolved, and then heat under reflux for 5 hours;

[0088] After cooling, the filter cake was filtered, and then washed five times each with water, ethanol, and acetone to ensure thorough cleaning. The resulting filter cake was then freeze-dried for 48 hours until its mass no longer decreased, thus obtaining the aqueous organic negative electrode active material HATNQ.

[0089] 2) Preparation of aqueous organic anode:

[0090] The HATNQ obtained in step 1) is mixed with Ketjen Black and polytetrafluoroethylene in a mass ratio of 4.5:4.5:1. Deionized water is added, and the mixture is ground in an agate mortar for 40 minutes. The mixture is then placed in a vacuum drying oven at 40°C for 40 minutes. The material is then kneaded into a clay-like consistency and pressed into a thin sheet to obtain the water-based organic negative electrode.

[0091] The remaining steps and processes are the same as in Example 2, and the aqueous battery of this example is obtained.

[0092] Figure 8 These are the charge-discharge curves of the battery prepared in this embodiment at 0.5 A / g for the 1st, 5th, and 15th cycles. The reversible capacities at 0.5 A / g for the 1st, 5th, 10th, and 15th cycles are 341.16 mAh / g, 295.18 mAh / g, 269.76 mAh / g, and 253.45 mAh / g, respectively.

[0093] Comparative Example 3

[0094] This comparative example (V-3) provides another method for synthesizing HATNQ, specifically:

[0095]

[0096] Add 60 ml of acetic acid / ethanol (volume ratio 1:1) to a 250 ml three-necked flask, add 0.624 g of cyclohexanehexanone octahydrate, and stir thoroughly until the reactants are completely dissolved.

[0097] N2 protection was introduced for 15 minutes, then 1.22g DANQ was slowly added and stirred thoroughly until dissolved. Then the mixture was heated under reflux for 20 hours.

[0098] After cooling, the filter cake was filtered, and then washed five times each with water, ethanol, and acetone to ensure thorough cleaning. The resulting filter cake was then freeze-dried for 48 hours until its mass no longer decreased, thus obtaining the aqueous organic negative electrode active material HATNQ.

[0099] Following the method in Embodiment 2 of this invention, the obtained HATNQ cells were assembled into full cells for performance testing. Figure 9 The charge-discharge curves of the full cell prepared in this comparative example are shown for the 1st, 5th, and 15th cycles at 0.5 A / g. The reversible capacities for the 1st, 5th, 10th, and 15th cycles at 0.5 A / g are 268.69 mAh / g, 263.61 mAh / g, 242.71 mAh / g, and 232.18 mAh / g, respectively.

[0100] Comparative Example 4

[0101] This comparative example synthesizes HATNQ according to the literature "Supramolecular Self-Assembled Multi-Electron-Acceptor Organic Molecule as High-Performance Cathode Material for Li-IonBatteries", and assembles the obtained HATNQ into a full cell for performance testing according to the method in Example 2 of this invention.

[0102] Comparative Example 5

[0103] The difference between this comparative example and Example 2 is that the molar ratio of cyclohexanehexanone to DANQ in step 1) was adjusted to 1:4. The remaining steps were the same as in Example 2. As a result, the product contained too many byproducts and was not suitable for further use as a negative electrode material to prepare batteries.

[0104] The performance test results of the full cells prepared in Example 2 and Comparative Examples 2-4 are shown in Table 1.

[0105] Table 1

[0106]

[0107]

[0108] As can be seen from Table 1, the negative electrode active material prepared in Example 2 of this invention exhibits superior electrochemical performance compared to other synthesis methods. This invention combines the advantages of quinone and azine materials, and designs a small molecule π-conjugated material (HATNQ) with multiple active centers based on azine materials. Due to the abundance of carbonyl and C=N groups in this material, it can provide a high theoretical capacity.

[0109] This invention optimizes the synthesis process of HATNQ material by incorporating conductive materials during synthesis. This allows the HATNQ material to grow within the micropores or mesopores of the conductive material, promoting uniform composite composition. This also enhances the electrochemical performance of HATNQ. Furthermore, combining this material with commercially available sintered nickel cathodes to construct an aqueous battery offers advantages such as readily available and inexpensive raw materials, effectively addressing the issue of high cost in existing aqueous batteries.

[0110] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing an aqueous organic negative electrode active material, characterized in that: include, The compound shown in formula (I) was dissolved in acetonitrile and then o-phenylenediamine was added. The mixture was stirred and refluxed under N2 atmosphere to obtain the compound shown in formula (II). The compound shown in formula (II) was mixed with hydrazine hydrate, heated and stirred, cooled and filtered, and then recrystallized in ethanol to obtain the compound shown in formula (III). The compound represented by formula (II) is mixed with hydrazine hydrate and heated for 1.5 to 2.5 hours at a temperature of 55 to 65°C. The conductive agent Ketjen black was dispersed in an acetic acid solution, ultrasonically stirred, and cyclohexanehexanone octahydrate was added. After stirring, the mixture was allowed to stand under vacuum to obtain the reaction solution. Under N2 atmosphere, the compound shown in formula (III) is added to the reaction solution, wherein the molar ratio of the octahydrate cyclohexanehexanone to the compound shown in formula (III) is 1:3~3.

2. After stirring, the mixture is heated to reflux and the reaction is completed. After the reaction is completed, the product is cooled, filtered, washed and freeze-dried to obtain the aqueous organic anode material. Equation (I); Formula (II); Formula (III).

2. The aqueous organic negative electrode active material prepared by the preparation method according to claim 1, characterized in that: The structural formula of the aqueous organic negative electrode material is shown in formula (IV); Formula (IV).

3. An aqueous organic negative electrode, characterized in that: Includes the aqueous organic negative electrode active material as described in claim 2.

4. The aqueous organic negative electrode as described in claim 3, characterized in that: The aqueous organic anode also includes polytetrafluoroethylene (PTFE); wherein the mass ratio of PTFE to the aqueous organic anode material is 0.5~1:

9.

5. The method for preparing the aqueous organic negative electrode as described in claim 3, characterized in that: include, Aqueous organic anode active material is mixed with polytetrafluoroethylene and then deionized water is added to obtain a precursor solution; After grinding the precursor liquid, vacuum drying, mixing, and pressing are performed to obtain the aqueous organic anode.

6. An aqueous battery, characterized in that: Including the aqueous organic negative electrode as described in claim 3.

7. The aqueous battery as described in claim 6, characterized in that: The aqueous battery is assembled using the aqueous organic negative electrode as described in claim 3 as the negative electrode, KOH as the electrolyte, and sintered nickel as the positive electrode.

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