Organic self-charging flow batteries based on quinone molecules and their preparation methods

Abstract

This invention discloses an organic self-charging flow battery based on quinone molecules and its preparation method, belonging to the field of battery fabrication technology. This invention uses sodium anthraquinone sulfonate derivatives as the positive electrode material to prepare the organic self-charging flow battery. Anthraquinone derivatives possess excellent electrochemical reversibility and high energy density. The electrical energy provided by sodium anthraquinone sulfonate molecules depends on the gain and loss of electrons in the reversible C=O and C-O reaction process; when exposed to air, it can naturally self-charge; when air is introduced, the positive electrode can return to its pre-discharge state. The organic self-charging flow battery based on quinone molecules provided by this invention increases battery capacity and energy density, enabling ultra-long-term cycling, effectively solving the problems of low energy density and limited capacity in traditional zinc organic flow batteries.

Description

Technical Field

[0001] This invention relates to the field of battery manufacturing technology, specifically to an organic self-charging flow battery based on quinone molecules and its manufacturing method. Background Technology

[0002] As global fossil fuel consumption leads to environmental problems, the demand for renewable energy is rapidly increasing. The instability and intermittency of electricity generated by renewable energy sources is a major obstacle to their widespread application. Energy storage technology, especially flow battery technology, is a safe and effective way to solve this problem. Currently, flow batteries can be divided into traditional flow batteries such as vanadium redox flow batteries, zinc-based flow batteries, and iron-chromium flow batteries, as well as newer flow battery systems such as organic flow batteries, which show great promise for energy storage applications. Among these flow batteries, zinc-based flow batteries, which utilize the plating and stripping process of the zinc redox couple at the negative electrode, have promising applications in distributed energy storage due to their attractive characteristics such as high safety, high energy density, and low cost. Compared to the energy density of vanadium redox flow batteries (25-35 Wh / L) and iron-chromium flow batteries (10-20 Wh / L), the energy density of zinc-bromine flow batteries (40-90 Wh / L) and zinc-iodine flow batteries (-167 Wh / L) is much higher due to the high solubility of halide ions and high battery voltage. However, their drawbacks include low valence charge, limited electron transfer capacity, high corrosivity, and the need to operate in corrosive electrolyte solutions such as concentrated sulfuric acid. While vanadium redox flow batteries (RFBs) have been commercialized, the scarcity of vanadium makes them expensive, and its toxicity raises safety concerns. Zinc-based flow battery technology is considered a promising distributed energy storage solution. However, their upgrades for practical applications still face challenges, such as the limited area capacity of dendritic zinc and the anode, relatively low power density, and reliability.

[0003] Aqueous aluminum batteries possess advantages such as abundant raw materials, low cost, high safety, and high theoretical capacity, making them a promising post-lithium battery technology for large-scale energy storage applications. However, the electrochemical behavior of aluminum metal electrodes is unsatisfactory due to the presence of an oxide layer and hydrogen side reactions, hindering their development.

[0004] Redox-active organic and organometallic molecules have been extensively studied due to their promise for developing inexpensive flow batteries. These molecules exhibit structural diversity and broad tunability, allowing for the engineering of solubility, redox potential, kinetics, and stability. Many different types of molecules, including quinones, phenazines, ionoalkaloids, pyrazines, and (2,2,6,6-tetramethylpiperidin-1-acyl) oxides, have shown good redox activity in aqueous organic redox flow batteries (AORFBs).

[0005] Most of these molecules exhibit low reduction potentials and have therefore been explored as negative electrolyte materials. Tetrachloro-1,4-benzoquinone and 4,5-dihydroxybenzene-1,3-disulfonic acid are exceptions, possessing high positive reduction potentials (>0.8 V) relative to the Standard Hydrogen Electrode (SHE) in acidic solutions. Therefore, by combining these high-potential organic molecules with Zn / [Zn(OH)4]... 2- Redox couple pairing can be used to design a novel hybrid RFB to achieve high battery voltage. However, due to H + or OH - Cross-conversion is difficult in traditional single-membrane RFBs, where it is challenging to pair alkaline and acidic electrolytes. In recent years, ceramic and bipolar polymer membranes have been introduced into single-membrane pH differential batteries, but the high resistance of these membranes severely limits the current density. Summary of the Invention

[0006] To address the aforementioned shortcomings in the prior art, this invention provides an organic self-charging flow battery based on quinone molecules and its preparation method. The anthraquinone derivatives used in the organic self-charging flow battery based on quinone molecules provided by this invention have excellent electrochemical reversibility, effectively solving the problems of low energy density and limited battery capacity in traditional zinc organic flow batteries.

[0007] To achieve the above objectives, the technical solution adopted by the present invention to solve its technical problem is: to provide an organic self-charging flow battery based on quinone molecules, wherein the positive electrode electrolyte of the organic self-charging flow battery based on quinone molecules includes sodium anthraquinone-2,7-disulfonate, inorganic salt, ammonium chloride and sulfuric acid, and the negative electrode electrolyte of the organic self-charging flow battery based on quinone molecules includes inorganic salt, ammonium chloride and sulfuric acid.

[0008] Furthermore, the inorganic salts in both the positive and negative electrode electrolytes are one of zinc trifluoromethanesulfonate, magnesium sulfate, and aluminum chloride.

[0009] The above-mentioned method for preparing the organic self-charging flow battery based on quinone molecules includes the following steps:

[0010] S1. Sodium anthraquinone-2,7-disulfonate, inorganic salt, ammonium chloride and sulfuric acid are added to deionized water and stirred evenly. Then, the mixture is sonicated and then subjected to aeration and bubbling treatment to obtain the positive electrode electrolyte.

[0011] S2. Add inorganic salts, ammonium chloride and sulfuric acid to deionized water and stir evenly, then perform ultrasonic treatment to obtain negative electrode electrolyte;

[0012] S3. Cut the ion exchange membrane and then activate it through pretreatment;

[0013] S4. Ultrasonically assemble each component of the battery, then separate the positive and negative electrodes with an ion membrane. Use a peristaltic pump to pump the positive electrolyte obtained in step S1 and the negative electrolyte obtained in step S2 into the battery. Then perform a resistance test to obtain an organic self-charging flow battery based on quinone molecules.

[0014] Furthermore, in step S1, the volume of the positive electrode electrolyte is 5-15 mL.

[0015] Furthermore, in step S1, the volume of the positive electrode electrolyte is 10 mL.

[0016] Furthermore, in step S1, the concentration of sodium anthraquinone-2,7-disulfonate in the positive electrode electrolyte is 0.05-0.15 mol / L.

[0017] Furthermore, in step S1, the concentration of sodium anthraquinone-2,7-disulfonate in the positive electrode electrolyte is 0.1 mol / L.

[0018] Furthermore, in step S1, the concentration of inorganic salt in the positive electrode electrolyte is 0.15-0.25 mol / L.

[0019] Furthermore, in step S1, the concentration of inorganic salt in the positive electrode electrolyte is 0.2 mol / L.

[0020] Furthermore, in step S1, the concentration of ammonium chloride in the positive electrode electrolyte is 0.5-1.5 mol / L.

[0021] Furthermore, in step S1, the concentration of ammonium chloride in the positive electrode electrolyte is 1 mol / L.

[0022] Furthermore, in step S1, the concentration of sulfuric acid in the positive electrode electrolyte is 0.05-0.15 mol / L.

[0023] Furthermore, in step S1, the concentration of sulfuric acid in the positive electrode electrolyte is 0.1 mol / L.

[0024] Furthermore, in steps S1 and S2, ultrasound is performed for 2-4 minutes.

[0025] Furthermore, in steps S1 and S2, ultrasound is performed for 3 minutes.

[0026] The beneficial effect of taking the above-mentioned further measures is that it makes the active substances in the solution more evenly distributed.

[0027] Furthermore, in step S1, argon gas is bubbled through for 4-6 minutes.

[0028] Furthermore, in step S1, argon gas is bubbled through for 5 minutes.

[0029] The beneficial effect of taking the above-mentioned further measures is to remove residual air from the electrolyte solution.

[0030] Furthermore, in step S2, the volume of the negative electrode electrolyte is 5-15 mL.

[0031] Furthermore, in step S2, the volume of the negative electrode electrolyte is 10 mL.

[0032] Furthermore, in step S2, the concentration of inorganic salt in the negative electrode electrolyte is 0.15-0.25 mol / L.

[0033] Furthermore, in step S2, the concentration of inorganic salt in the negative electrode electrolyte is 0.2 mol / L.

[0034] Furthermore, in step S2, the concentration of ammonium chloride in the negative electrode electrolyte is 0.5-1.5 mol / L.

[0035] Furthermore, in step S2, the concentration of ammonium chloride in the negative electrode electrolyte is 1 mol / L.

[0036] Furthermore, in step S2, the concentration of sulfuric acid in the negative electrode electrolyte is 0.05-0.15 mol / L.

[0037] Furthermore, in step S2, the concentration of sulfuric acid in the negative electrode electrolyte is 0.1 mol / L.

[0038] Furthermore, in step S3, the dimensions of the ion exchange membrane are: 3cm × 3cm.

[0039] Furthermore, in step S3, the ion exchange membrane is a perfluorosulfonic acid membrane.

[0040] The benefits of adopting the above-mentioned further solutions are: improving ion transport efficiency and reducing the overall internal resistance after battery assembly, thus avoiding unnecessary voltage loss.

[0041] Further, in step S3, the pretreatment includes the following steps: immersing the ion exchange membrane in a 4-6 wt% hydrogen peroxide solution and heating it in a water bath at 75-85°C for 0.5-1.5 h; then immersing the ion exchange membrane in a 4-6 wt% sulfuric acid solution and heating it in a water bath at 75-85°C for 0.5-1.5 h; and finally washing away the residual acidic solution with deionized water.

[0042] Furthermore, in step S3, the pretreatment includes the following steps: immersing the ion exchange membrane in a 5 wt% hydrogen peroxide solution and heating it in a water bath at 80°C for 1 hour; then immersing the ion exchange membrane in a 5 wt% sulfuric acid solution and heating it in a water bath at 80°C for 1 hour; and finally washing away the residual acidic solution with deionized water.

[0043] Furthermore, in step S4, the battery components include a metal plate, a rubber pad, a conductive copper plate, a carbon felt, and a graphite channel.

[0044] Furthermore, the specifications of the carbon felt are: 2cm long × 2cm wide × 3mm thick.

[0045] Furthermore, in step S4, the mixture is sonicated with anhydrous ethanol for 2-4 minutes.

[0046] Furthermore, in step S4, the mixture is sonicated with anhydrous ethanol for 3 minutes.

[0047] The present invention has the following beneficial effects:

[0048] 1. This invention selects the best-performing molecules from a series of anthraquinone derivatives containing sodium sulfonate groups. The organic self-charging flow battery based on quinone molecules provided by this invention has the following characteristics: it uses sodium anthraquinone sulfonate derivatives as the positive electrode material, and zinc and zinc ions, aluminum and aluminum ions, or magnesium and magnesium ions as the negative electrode active materials. Anthraquinone derivatives have excellent electrochemical reversibility and high energy density. The electrical energy provided by sodium anthraquinone sulfonate molecules depends on the gain and loss of electrons in the reversible reaction process of C=O and CO. When exposed to air, it can naturally self-charge; when air is introduced, the positive electrode of the battery can return to its pre-discharge state. This invention will broaden the application scope of zinc organic water batteries and provide an effective strategy for developing self-charging energy storage devices.

[0049] 2. The organic self-charging flow battery based on quinone molecules prepared by the method provided in this invention increases the capacity of the organic flow battery itself, thereby increasing the energy density of the battery; and it can undergo ultra-long-term cycling with good capacity retention.

[0050] 3. Oxygen is a readily available and low-cost resource in nature. Combining the chemical energy of oxygen with the electrochemical energy of electrode materials is an effective way to obtain high-energy battery systems. Utilizing it to increase battery capacity is also an effective solution to the cost problem brought about by large-scale energy storage of flow batteries.

[0051] 4. Anthraquinone derivatives containing carbonyl groups (C=O) and possessing conjugated structures exhibit excellent electrochemical reversibility and rapid reaction rates, making them undoubtedly excellent active materials for aqueous flow batteries. Anthraquinone derivatives with sulfonic acid groups, in particular, are preferred as electrode active materials in acidic aqueous flow batteries due to their good solubility in acidic aqueous solutions. However, their voltage is relatively low, and they are typically used as negative electrode active materials. This invention selects quinones paired with zinc and adjusts the battery voltage under acidic conditions. Furthermore, anthraquinone derivatives possess carbon-oxygen double bonds (C=O) and reduced carbon-oxygen bonds (CO), which can be oxidized by oxygen to convert carbon-oxygen single bonds to carbon-oxygen double bonds, restoring the positive electrode discharge products to their original state and achieving self-charging. Attached Figure Description

[0052] Figure 1 The graph shows the changes in battery capacity and retention rate of an organic self-charging flow battery based on quinone molecules as a function of cycle number.

[0053] Figure 2 The graph shows the change of open-circuit voltage over time for organic self-charging flow batteries based on quinone molecules under different conditions.

[0054] Figure 3 The in-situ infrared spectroscopy results of the discharge products at different oxidation times are shown in the figure.

[0055] Figure 4 The image shows the UV test results of the discharge products at different oxidation times.

[0056] Figure 5 Figure 1 shows the self-charging cycle performance of zinc-based batteries.

[0057] Figure 6 Figure showing the self-charging cycle performance of magnesium-based materials;

[0058] Figure 7 A graph showing the self-charging cycle performance of an aluminum-based substrate;

[0059] Figure 8 A graph showing the relationship between inflation time and theoretical capacity;

[0060] Figure 9 The figure shows the internal resistance test results of an organic self-charging flow battery based on quinone molecules. Detailed Implementation

[0061] The principles and features of this invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified, specific conditions in the examples are performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products. The ion-exchange membrane used in the examples is a Dongyue perfluorosulfonic acid membrane.

[0062] Example 1

[0063] The preparation method of organic self-charging flow battery based on quinone molecules includes the following steps:

[0064] S1. Add sodium anthraquinone-2,7-disulfonate, zinc trifluoromethanesulfonate, ammonium chloride, and sulfuric acid to deionized water and stir until homogeneous. Then sonicate for 3 minutes and bubble with argon gas for 5 minutes to obtain 10 mL of positive electrode electrolyte. The concentration of sodium anthraquinone-2,7-disulfonate in the positive electrode electrolyte is 0.1 mol / L, the concentration of zinc trifluoromethanesulfonate in the positive electrode electrolyte is 0.2 mol / L, the concentration of ammonium chloride in the positive electrode electrolyte is 1 mol / L, and the concentration of sulfuric acid in the positive electrode electrolyte is 0.1 mol / L.

[0065] S2. Add zinc trifluoromethanesulfonate, ammonium chloride and sulfuric acid to deionized water and stir until homogeneous. Then sonicate for 3 minutes to obtain 10 mL of negative electrode electrolyte. The concentration of zinc trifluoromethanesulfonate in the positive electrode electrolyte is 0.2 mol / L, the concentration of ammonium chloride in the positive electrode electrolyte is 1 mol / L, and the concentration of sulfuric acid in the positive electrode electrolyte is 0.1 mol / L.

[0066] S3. Cut the perfluorosulfonic acid membrane to 3cm×3cm, then immerse it in a 5wt% hydrogen peroxide solution and heat it in a water bath at 80℃ for 1 hour. Then immerse the ion membrane in a 5wt% sulfuric acid solution and heat it in a water bath at 80℃ for 1 hour. Finally, wash away the residual acidic solution with deionized water.

[0067] S4. The metal plates, rubber pads, conductive copper plates, carbon felt (2cm long × 2cm wide × 3mm thick) and graphite flow channels of each battery component are ultrasonicated with anhydrous ethanol for 3 minutes, and then spliced ​​together in sequence. The positive and negative electrodes are then separated by a perfluorosulfonic acid membrane. The positive electrolyte obtained in step S1 and the negative electrolyte obtained in step S2 are pumped into the battery using a peristaltic pump. The resistance is then tested to obtain an organic self-charging flow battery based on quinone molecules.

[0068] Example 2

[0069] The preparation method of organic self-charging flow battery based on quinone molecules includes the following steps:

[0070] S1. Add sodium anthraquinone-2,7-disulfonate, aluminum chloride, ammonium chloride, and sulfuric acid to deionized water and stir until homogeneous. Then sonicate for 2 minutes and bubble with argon gas for 4 minutes to obtain 10 mL of positive electrode electrolyte. The concentration of sodium anthraquinone-2,7-disulfonate in the positive electrode electrolyte is 0.05 mol / L, the concentration of magnesium sulfate in the positive electrode electrolyte is 0.15 mol / L, the concentration of ammonium chloride in the positive electrode electrolyte is 0.5 mol / L, and the concentration of sulfuric acid in the positive electrode electrolyte is 0.05 mol / L.

[0071] S2. Add aluminum chloride, ammonium chloride and sulfuric acid to deionized water and stir evenly. Then sonicate for 2 minutes to obtain 10 mL of negative electrode electrolyte. The concentration of magnesium sulfate in the positive electrode electrolyte is 0.15 mol / L, the concentration of ammonium chloride in the positive electrode electrolyte is 0.5 mol / L, and the concentration of sulfuric acid in the positive electrode electrolyte is 0.05 mol / L.

[0072] S3. Cut the perfluorosulfonic acid membrane to 3cm×3cm, then immerse it in a 4wt% hydrogen peroxide solution and heat it in a water bath at 75℃ for 0.5h. Then immerse the ion membrane in a 4wt% sulfuric acid solution and heat it in a water bath at 75℃ for 0.5h. Finally, wash away the residual acidic solution with deionized water.

[0073] S4. The metal plates, rubber pads, conductive copper plates, carbon felt (2cm long × 2cm wide × 3mm thick) and graphite flow channels of each battery component are ultrasonicated with anhydrous ethanol for 2 minutes, then assembled in sequence. The positive and negative electrodes are then separated by a perfluorosulfonic acid membrane. The positive electrolyte obtained in step S1 and the negative electrolyte obtained in step S2 are pumped into the battery using a peristaltic pump. The resistance is then tested to obtain an organic self-charging flow battery based on quinone molecules.

[0074] Example 3

[0075] The preparation method of organic self-charging flow battery based on quinone molecules includes the following steps:

[0076] S1. Add sodium anthraquinone-2,7-disulfonate, magnesium sulfate, ammonium chloride, and sulfuric acid to deionized water and stir until homogeneous. Then sonicate for 4 min and bubble with argon gas for 6 min to obtain 10 mL of positive electrode electrolyte. The concentration of sodium anthraquinone-2,7-disulfonate in the positive electrode electrolyte is 0.15 mol / L, the concentration of aluminum chloride in the positive electrode electrolyte is 0.25 mol / L, the concentration of ammonium chloride in the positive electrode electrolyte is 1.5 mol / L, and the concentration of sulfuric acid in the positive electrode electrolyte is 0.15 mol / L.

[0077] S2. Add magnesium sulfate, ammonium chloride and sulfuric acid to deionized water and stir until homogeneous. Then sonicate for 4 min to obtain 10 mL of negative electrode electrolyte. The concentration of aluminum chloride in the positive electrode electrolyte is 0.25 mol / L, the concentration of ammonium chloride in the positive electrode electrolyte is 1.5 mol / L, and the concentration of sulfuric acid in the positive electrode electrolyte is 0.15 mol / L.

[0078] S3. Cut the perfluorosulfonic acid membrane to 3cm×3cm, then immerse it in a 6wt% hydrogen peroxide solution and heat it in a water bath at 85℃ for 1.5h. Then immerse the ion membrane in a 6wt% sulfuric acid solution and heat it in a water bath at 85℃ for 1.5h. Finally, wash away the residual acidic solution with deionized water.

[0079] S4. The metal plates, rubber pads, conductive copper plates, carbon felt (2cm long × 2cm wide × 3mm thick) and graphite flow channels of each battery component are ultrasonicated with anhydrous ethanol for 4 minutes, then assembled in sequence. The positive and negative electrodes are then separated by a perfluorosulfonic acid membrane. The positive electrolyte obtained in step S1 and the negative electrolyte obtained in step S2 are pumped into the battery using a peristaltic pump. The resistance is then tested to obtain an organic self-charging flow battery based on quinone molecules.

[0080] Experimental Example 1

[0081] The organic self-charging flow battery based on quinone molecules prepared in Example 1 was subjected to charge-discharge cycles, and the results are as follows: Figure 1 As shown. In the open-cell battery, the electrolyte is kept in a flowing state by a pump throughout the entire cycle. In the sealed-cell battery, the electrolyte is pumped into the flow cell before cycling to fill the channels; no flow cycling is required.

[0082] Depend on Figure 1 It can be seen that the battery capacity is about 2mAh in the absence of air, and it still retains nearly 100% capacity after 1600 cycles.

[0083] Experimental Example 2

[0084] In-situ infrared characterization showed that the sodium anthraquinone sulfonate molecule provides electrical energy depending on the gain and loss of electrons during the reversible reaction of C=O and CO. When exposed to air, it can naturally self-charge. After air is introduced, the battery's positive electrode can return to its pre-discharge state, and this process can be repeated 20 times, reaching a capacity of 100mAh. Clearly, the discharge capacity of a normally cycled battery is higher than that of a statically stored battery, which may be related to dissolved oxygen in the electrolyte. To verify this viewpoint, the open-circuit voltage (OCV) test was performed on the quinone-based organic self-charging flow battery prepared in Example 1 to study the stability of the organic discharge products under different gas conditions. The results are as follows: Figure 2 As shown.

[0085] Depend on Figure 2 It was found that when a normally cycled battery was discharged to 0.01V, and then subjected to a gas purging step under different gas conditions, the battery's OCV (Optical Voltage Capacity) increased rapidly when a pure O2 gas flow was introduced into the electrolyte, reaching the equilibrium voltage within 10 minutes. However, under Ar2 conditions, even with a purging time exceeding 10 minutes, the OCV failed to reach the equilibrium voltage, remaining essentially constant at 0.82V. This result indicates that the battery can operate stably in the absence of air, and the organic molecular structure remains unchanged.

[0086] Experimental Example 3

[0087] The results of Experiment 2 show that the battery discharge products can be oxidized by dissolved oxygen, and the oxidation rate depends on the oxygen concentration. To further investigate, in-situ infrared spectroscopy was performed to analyze the chemical redox process in depth. The organic self-charging flow battery (2,7-ADQS||Zn / Zn) based on quinone molecules prepared in Example 1 was used. 2+ (flow battery) at 20mA cm -2 The cathode electrolyte was discharged at a low current density to 0.01V, and then subjected to an oxygen-bubbling experiment to react with oxygen. The in-situ infrared spectroscopy results of the discharge products at different oxidation times are shown below. Figure 3 As shown.

[0088] Depend on Figure 3 It can be seen that as the bubbling time changes, 3200cm -1 1600cm -1 The absorption intensity gradually increases at the left and right sides, indicating that the C=O functional groups gradually increase, representing that the discharge products are gradually oxidized to a charged state throughout the process.

[0089] Test Example 4

[0090] The UV test results of the discharge products of the organic self-charging flow battery based on quinone molecules prepared in Example 1 under different oxidation times are as follows: Figure 4 As shown.

[0091] Depend on Figure 4 It can be seen that with the increase of oxidation time, the peak absorption intensity at 329 nm gradually increases, while the peak absorption intensity at 388 nm gradually decreases, proving that the C=O functional group increases and the CO functional group decreases. After 8 minutes of oxidation, the UV absorption peak curve basically coincides with the UV absorption peak curve after the first discharge, representing the excellent electrochemical reversibility of sodium anthraquinone-2,7-disulfonate.

[0092] In summary, the products after complete discharge can spontaneously react with dissolved oxygen in the acidic electrolyte and return to their pre-discharge state (i.e., sodium anthraquinone-2,7-disulfonate), directly increasing the battery capacity without the need for an external power source. This process is known as chemical self-charging. Specifically, in an acidic electrolyte (0.2M H₂SO₄ + 0.2M ZnOTF₂), the discharge products of sodium anthraquinone-2,7-disulfonate couple with the zinc negative electrode to form a chemically self-charging battery.

[0093] Experimental Example 5

[0094] The organic self-charging flow batteries based on quinone molecules prepared in Examples 1, 2, and 3, after 1 minute of oxidation (i.e., chemical self-charging), exhibit the following OCV and discharge capacity: Figures 5-7 As shown.

[0095] Depend on Figure 5 It can be seen that after 1 minute of oxidation, the OCV of the self-rechargeable battery prepared in Example 1 recovered to 0.52V, and the voltage was within 40 mA / cm². -2 At the specified current density, the discharge capacity can reach 5mAh. After repeated 1-minute oxygenation (chemical self-charging) and discharge cycles, the capacity retention rate remained essentially unchanged after 20 cycles, with a cumulative capacity of approximately 100mAh, demonstrating its stability.

[0096] Depend on Figure 6 It can be seen that after 1 minute of oxidation, the OCV of the self-rechargeable battery prepared in Example 2 recovered to 0.5V, and the voltage remained at 40 mA / cm². -2 At the specified current density, the discharge capacity reaches 5.5 mAh. After repeated 1-minute oxygenation (chemical self-charging) and discharge cycles, the capacity retention remains essentially unchanged after 20 cycles, with a cumulative capacity of approximately 110 mAh, demonstrating its stability.

[0097] Depend on Figure 7 It can be seen that after 1 minute of oxidation, the OCV of the self-rechargeable battery prepared in Example 3 recovered to 0.65V, and at 40mAcm -2 At the specified current density, the discharge capacity can reach 1.8 mAh. After repeated 1-minute oxygenation (chemical self-charging) and discharge cycles, the capacity retention rate remained essentially unchanged after 20 cycles, with a cumulative capacity of approximately 18 mAh, demonstrating its stability.

[0098] Subsequently, constant current discharge curves of the discharged battery after oxidation at different times were collected, and the results are as follows: Figure 8 As shown.

[0099] Depend on Figure 8It can be seen that the open-circuit voltage of the self-charging flow battery based on quinone molecules increases with oxidation time, and the discharge capacity also improves. The figure shows that when the oxidation time is extended to 16 minutes, the ratio of its discharge capacity to the theoretical discharge capacity is close to 100%.

[0100] Experimental Example 6

[0101] The positive and negative electrodes of the quinone-based organic self-charging flow battery prepared in Example 1 were connected to the Chenhua electrochemical workstation. The working electrode and reference electrode were connected to the positive electrode, and the counter electrode was connected to the negative electrode. The internal resistance was tested using the AC impendence program, and the results are as follows: Figure 9 As shown.

[0102] Depend on Figure 9 As can be seen, after the battery is assembled, the internal resistance is basically normal after EIS testing, and it will not affect the experimental results.

[0103] In summary, this invention successfully constructed a sodium anthraquinone-2,7-disulfonate positive electrode and a zinc negative electrode for batteries in an acidic electrolyte (i.e., 0.2 M H₂SO₄ + 0.2 M Zn(OTF)₂). The experimental results above show that at 40 mA cm⁻¹... -2 Under certain conditions, the organic self-charging flow battery (2,7-AQDS / / Zn) based on quinone molecules exhibits a specific capacity of 1250 mAh, good cycle stability (reaching 100% after 1200 cycles), and good rate performance in the absence of O2. UV absorption and in-situ Fourier transform infrared analysis identified the C=O group of sodium anthraquinone-2,7-disulfonate as the redox active center, revealing a reversible C=O / CO charge storage mechanism. When the battery is exposed to air, the positive electrode discharge products can be oxidized by dissolved oxygen in the electrolyte, restoring the battery to its initial state. Therefore, after the 2,7-AQDS / / Zn battery is depleted, a chemical self-charging process can be achieved by exposing the battery to an air atmosphere. The battery can rapidly self-charge to 0.9V. This chemical charge / constant current discharge process can be rapidly and reversibly repeated 20 times.

[0104] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An organic self-charging flow battery based on quinone molecules, characterized in that, The positive electrode electrolyte of the organic self-charging flow battery based on quinone molecules includes sodium anthraquinone-2,7-disulfonate, inorganic salt, ammonium chloride, and sulfuric acid; the negative electrode electrolyte of the organic self-charging flow battery based on quinone molecules includes inorganic salt, ammonium chloride, and sulfuric acid. The inorganic salts in both the positive electrode electrolyte and the negative electrode electrolyte are one of zinc trifluoromethanesulfonate, aluminum chloride, and magnesium sulfate. The method for preparing the organic self-charging flow battery based on quinone molecules is characterized by comprising the following steps: S1. Sodium anthraquinone-2,7-disulfonate, inorganic salt, ammonium chloride, and sulfuric acid are added to deionized water and stirred until homogeneous. Then, the mixture is sonicated and subjected to argon bubbling to obtain a positive electrode electrolyte. The concentration of sodium anthraquinone-2,7-disulfonate in the positive electrode electrolyte is 0.05-0.15 mol / L, the concentration of inorganic salt is 0.15-0.25 mol / L, the concentration of ammonium chloride is 0.5-1.5 mol / L, and the concentration of sulfuric acid is 0.05-0.15 mol / L. S2. Add inorganic salt, ammonium chloride, and sulfuric acid to deionized water and stir until homogeneous. Then, perform ultrasonic treatment to obtain a negative electrode electrolyte. The concentration of the inorganic salt in the negative electrode electrolyte is 0.15-0.25 mol / L, the concentration of the ammonium chloride in the negative electrode electrolyte is 0.5-1.5 mol / L, and the concentration of the sulfuric acid in the negative electrode electrolyte is 0.05-0.15 mol / L. S3. Activate the ion exchange membrane through pretreatment; S4. The battery components are ultrasonically processed and then assembled sequentially. The positive and negative electrodes are separated by an ion exchange membrane. The positive electrolyte obtained in step S1 and the negative electrolyte obtained in step S2 are pumped into the battery using a peristaltic pump. The resistance is then tested to obtain an organic self-charging flow battery based on quinone molecules. After complete discharge, the product spontaneously reacts with dissolved oxygen in the acidic electrolyte and returns to the state before discharge, namely sodium anthraquinone-2,7-disulfonate, thus achieving self-charging without the need for an external power source, directly increasing the battery capacity.

2. The organic self-charging flow battery based on quinone molecules as described in claim 1, characterized in that, In steps S1 and S2, ultrasound is performed for 2-4 minutes.

3. The organic self-charging flow battery based on quinone molecules as described in claim 1, characterized in that, In step S1, argon gas is bubbled through for 4-6 minutes.

4. The organic self-charging flow battery based on quinone molecules as described in claim 1, characterized in that, In step S3, the ion exchange membrane is a perfluorosulfonic acid membrane.

5. The organic self-charging flow battery based on quinone molecules as described in claim 1, characterized in that, In step S3, the pretreatment includes the following steps: immersing the ion exchange membrane in a 4-6 wt% hydrogen peroxide solution and heating it in a water bath at 75-85 ℃ for 0.5-1.5 h; then immersing the ion exchange membrane in a 4-6 wt% sulfuric acid solution and heating it in a water bath at 75-85 ℃ for 0.5-1.5 h; and finally washing away the residual acidic solution with deionized water.

6. The organic self-charging flow battery based on quinone molecules as described in claim 1, characterized in that, In step S4, each component of the battery includes a metal plate, a rubber pad, a conductive copper plate, and a graphite flow channel.

7. The organic self-charging flow battery based on quinone molecules as described in claim 1, characterized in that, In step S4, sonicate with anhydrous ethanol for 2-4 minutes.

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