Acid flow battery, negative electrode electrolyte of acid flow battery and preparation method of negative electrode electrolyte
By designing a negative electrode electrolyte containing iron salts and complexing agents in the acidic flow battery, the problems of defects in the acidic deposition type and alkaline complexing type flow battery in the prior art are solved, and more efficient and more Safe battery performance.
Patent Information
- Application Number
- CN202410624624.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-20
- Publication Date
- 2025-02-11
AI Technical Summary
The existing iron-based flow batteries have defects in the acidic deposition type and the alkali complex type, and cannot take into account the advantages of both. The active substances are unstable in an acidic environment, which affects battery efficiency and safety.
Provide an negative electrode electrolyte of an acidic flow battery, including iron salt and complexing agent, the molar concentration ratio of the complexing agent and iron salt is 0.8 to 2.5, and the pH range is 1-4. The pH and concentration are adjusted by the preparation method. to form a stable electrolyte.
The advantages of taking into account both the acidic deposition type and the alkaline complex flow battery under acidic conditions are achieved, the battery efficiency and the conduction ability of the separator to hydrogen ions are improved, and the safety of the battery and the stability of the active substances are enhanced.
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Figure CN119419323A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of liquid flow batteries, and in particular to an acidic liquid flow battery and a negative electrode electrolyte thereof, and a method for preparing the negative electrode electrolyte. Background Art
[0002] Existing iron-based liquid flow batteries mainly include acidic deposition type and alkaline complex type. The defect of the acidic deposition type is that the battery capacity is limited by the structure of the battery stack, and the negative electrode is prone to hydrogen precipitation, which affects the safety of the battery. The positive electrode may lose its activity due to the increase in pH, causing iron ions to generate iron hydroxide, resulting in poor battery parameter effects. The alkaline complex type is better than the acidic deposition type. Both the charging and discharging states are dissolved and will not precipitate, which is beneficial to the operation of the liquid flow battery. However, due to the strong alkaline environment, ferrocyanide may react with hydroxide, resulting in instability of the active substance and deactivation.
[0003] Therefore, it is necessary to develop a complex-type all-iron liquid flow battery under acidic conditions, which can combine the advantages of both aspects. Summary of the invention
[0004] The present application mainly provides an acidic liquid flow battery and its negative electrode electrolyte, and a method for preparing the negative electrode electrolyte, so as to solve the problem that the existing market lacks a liquid flow battery that can take into account the advantages of both acidic deposition type and alkaline complex type liquid flow batteries.
[0005] To solve the above technical problems, a technical solution adopted by the present application is: to provide a negative electrode electrolyte. The negative electrode electrolyte includes an iron salt and a complexing agent, the molar concentration ratio of the complexing agent to the iron salt is 0.8 to 2.5, and the pH range of the negative electrode electrolyte is 1-4.
[0006] In some embodiments, the iron salt includes ferrous chloride, ferrous sulfate, ferrous nitrate, ferric chloride, ferric sulfate, ferric oxyhydroxide, and ferric nitrate.
[0007] In some embodiments, the complexing agent includes sodium tripolyphosphate, potassium tripolyphosphate, potassium pyrophosphate, sodium pyrophosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, sodium dihydrogen phosphate, and potassium dihydrogen phosphate.
[0008] In some embodiments, the concentration of the iron salt ranges from 0.1 to 2.0 mol / L.
[0009] To solve the above technical problems, another technical solution adopted by the present application is to provide a method for preparing a negative electrode electrolyte. The preparation method comprises: preparing a first solution containing an iron salt; preparing a second solution containing a complexing agent; adjusting the pH of the second solution to 1-4; and gradually mixing the second solution after adjusting the pH with the first solution.
[0010] In some embodiments, the step of gradually mixing the second solution after adjusting the pH with the first solution comprises:
[0011] gradually adding the second solution to the first solution to obtain a mixed solution, and making the mixed solution to a preset volume with deionized water;
[0012] The mixed solution is allowed to react at a preset temperature for a preset time to obtain the negative electrode electrolyte.
[0013] In some embodiments, the preset temperature is 25°C to 95°C, and the preset time is 10 minutes to 24 hours.
[0014] In some embodiments, the acid used to adjust the pH of the second solution includes hydrochloric acid, phosphoric acid, sulfuric acid and nitric acid.
[0015] In order to solve the above technical problems, another technical solution adopted by the present application is to provide an acid liquid flow battery. The acid liquid flow battery includes the negative electrode electrolyte as described above.
[0016] In some embodiments, the separator of the acid flow battery is a perfluorosulfonic acid membrane or a porous membrane.
[0017] The beneficial effects of the present application are as follows: Different from the prior art, the present application discloses an acidic liquid flow battery and its negative electrode electrolyte, and a method for preparing the negative electrode electrolyte. By proposing a negative electrode electrolyte for an acidic liquid flow battery, the negative electrode electrolyte includes an iron salt and a complexing agent, the molar concentration ratio of the complexing agent to the iron salt is 0.8 to 2.5, and the pH range of the negative electrode electrolyte is 1-4. It belongs to a complexing type negative electrode electrolyte in an acidic system, which can take into account the advantages of both acidic deposition type and alkaline complexing type liquid flow batteries, and the liquid flow battery under the acidic system is also more conducive to the conduction of hydrogen ions by the diaphragm, which can effectively improve the battery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work, among which:
[0019] Figure 1 It is a schematic flow chart of an embodiment of a method for preparing a negative electrode electrolyte provided in the present application;
[0020] Figure 2 yes Figure 1 A schematic flow chart of an embodiment of step 40 in a method for preparing a negative electrode electrolyte;
[0021] Figure 3 This is a cyclic voltammetry curve of the charge and discharge test of the acid flow battery. DETAILED DESCRIPTION
[0022] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0023] The terms "first", "second", "third" in the embodiments of the present application are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first", "second", "third" can expressly or implicitly include at least one of the features. In the description of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or units inherent to these processes, methods, products or devices.
[0024] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.
[0025] The present application provides a negative electrode electrolyte for an acidic liquid flow battery, the negative electrode electrolyte comprising an iron salt and a chelating agent, the molar ratio of the chelating agent to the iron salt being 0.8 to 2.5, for example, the molar concentration ratio of the chelating agent to the iron salt may be 0.8, 0.9, 1.0, 1.1, 1.2, 1.4, 1.5, 1.8, 2.0, 2.3 or 2.5, etc.; the pH range of the negative electrode electrolyte is 1-4, for example, the pH may be 1.0, 1.2, 1.4, 1.5, 1.8, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.2, 3.4, 3.6, 3.8 or 4.0, etc.
[0026] Iron salts include ferrous chloride, ferrous sulfate, ferrous nitrate, ferric chloride, ferric sulfate, ferric oxyhydroxide and ferric nitrate. The iron salt in the negative electrode electrolyte can be at least one of the above, for example, ferrous chloride.
[0027] The concentration of the iron salt is in the range of 0.1 to 2.0 mol / L. For example, the concentration of the iron salt is 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L, 1.8 mol / L or 2.0 mol / L.
[0028] Complexing agents include sodium tripolyphosphate, potassium tripolyphosphate, potassium pyrophosphate, sodium pyrophosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, sodium dihydrogen phosphate, and potassium dihydrogen phosphate.
[0029] The present application also provides a method for preparing the negative electrode electrolyte of an acidic liquid flow battery, see Figure 1 , Figure 1 1 is a schematic flow chart of an embodiment of a method for preparing a negative electrode electrolyte provided in the present application, wherein the method for preparing a negative electrode electrolyte comprises:
[0030] Step 10: Prepare a first solution containing an iron salt.
[0031] A certain amount of iron salt is weighed and dissolved in an appropriate amount of deionized water to obtain a first solution. Specifically, the mass of the iron salt to be weighed is calculated based on the concentration of the iron salt to be prepared and its volume. For example, if the concentration of ferrous chloride to be prepared is 1 mol / L and the volume is 50 ml, and the molar mass of ferrous chloride is 126.75 g / moL, 6.3375 g of ferrous chloride needs to be weighed.
[0032] In this embodiment, 6.3375 g of ferrous chloride was weighed and dissolved in 10 ml of deionized water, which was recorded as the first solution.
[0033] Step 20: Prepare a second solution containing a complexing agent.
[0034] A certain amount of complexing agent is weighed and dissolved in an appropriate amount of deionized water to obtain a second solution. Specifically, the mass of the complexing agent to be weighed is calculated based on the concentration of the complexing agent to be prepared and its volume. For example, if the concentration of sodium tripolyphosphate to be prepared is 1 mol / L and the volume is 50 ml, and the molar mass of sodium tripolyphosphate is 367.86 g / moL, 18.393 of sodium tripolyphosphate needs to be weighed.
[0035] In this embodiment, 18.393 g of sodium tripolyphosphate was weighed and dissolved in 30 ml of deionized water, which was recorded as the second solution.
[0036] Step 30: Adjust the pH of the second solution to 1-4.
[0037] The pH value of the second solution is adjusted to 1-4 by using an appropriate amount of acid solution, wherein the acid solution used to adjust the pH value of the second solution includes hydrochloric acid, phosphoric acid, sulfuric acid and nitric acid.
[0038] In this embodiment, an appropriate amount of 10 mol / L hydrochloric acid is used to adjust the pH of the second solution to 1-4.
[0039] Step 40: gradually mixing the second solution after adjusting the pH with the first solution.
[0040] The second solution after adjusting the pH is gradually mixed with the first solution to finally obtain the desired negative electrode electrolyte.
[0041] In this embodiment, refer to Figure 2 , Figure 2 yes Figure 1 FIG. 4 is a flow chart of an embodiment of step 40 in a method for preparing a negative electrode electrolyte. Step 40 specifically includes:
[0042] Step 41: gradually add the second solution to the first solution to obtain a mixed solution, and dilute the mixed solution to a preset volume with deionized water.
[0043] The second solution is gradually added to the first solution to obtain a mixed solution. The volume of the mixed solution is less than the volume required for the negative electrode electrolyte. Deionized water can be used to make the volume to the required volume, and the concentrations of the iron salt and the complexing agent are also adjusted to the designed preset concentrations.
[0044] In this embodiment, the mixed solution is fixed to 50 ml with deionized water, wherein the molar concentration ratio of the complexing agent to the iron salt is 1.0, and the molar concentrations of the complexing agent and the iron salt are both 1.0 mol / L.
[0045] Step 42: Allow the mixed solution to react at a preset temperature for a preset time to obtain a negative electrode electrolyte.
[0046] The mixed solution needs to be further reacted to obtain the desired negative electrode electrolyte in an acidic system.
[0047] In this embodiment, the preset temperature is 25° C. to 95° C., and the preset time is 10 min to 24 h. That is, the mixed solution reacts at the preset temperature of 25° C. to 95° C. for 10 min to 24 h to obtain the negative electrode electrolyte.
[0048] If the reaction temperature exceeds 95°C, the acidic system will decompose and produce white precipitate, which will reduce the performance of the negative electrode electrolyte; if the reaction temperature is lower than 25°C, the reaction will not be sufficient, which will also result in insufficient performance of the negative electrode electrolyte. Therefore, the preset temperature during the reaction is set in this application so that the mixed solution can react fully and obtain a high-quality negative electrode electrolyte.
[0049] The present application also provides an acidic liquid flow battery, which includes a positive electrode electrolyte and a negative electrode electrolyte as described above, the positive electrode electrolyte and the negative electrode electrolyte have the same pH, and the positive electrode electrolyte and the negative electrode electrolyte are separated by a diaphragm, wherein the diaphragm can be a perfluorosulfonic acid membrane or a porous membrane.
[0050] In this embodiment, the negative electrode electrolyte uses ferrous ions, and the positive electrode electrolyte uses ferric ions. The positive electrode electrolyte can be ferric chloride hexahydrate, ferric sulfate or ferric nitrate solution.
[0051] Optionally, the negative electrode electrolyte uses ferric ions, and the positive electrode electrolyte uses ferrous ions.
[0052] See also Figure 3 , Figure 3 This is a cyclic voltammetry curve of the charge and discharge test of the acid flow battery. It can be seen that its oxidation peak is at -0.30V, the reduction peak is at -0.48V, and the 5th, 10th and 20th circles are almost completely overlapped, proving that the redox stability of the active substances in the negative electrode electrolyte is relatively strong.
[0053] Different from the prior art, the present application discloses an acidic liquid flow battery and its negative electrode electrolyte, and a method for preparing the negative electrode electrolyte. By proposing a negative electrode electrolyte for an acidic liquid flow battery, the negative electrode electrolyte includes an iron salt and a complexing agent, the molar concentration ratio of the complexing agent to the iron salt is 0.8 to 2.5, and the pH range of the negative electrode electrolyte is 1-4. It belongs to a complexing type negative electrode electrolyte in an acidic system, which can take into account the advantages of both acidic deposition type and alkaline complexing type liquid flow batteries, and the liquid flow battery under the acidic system is also more conducive to the conduction of hydrogen ions by the diaphragm, which can effectively improve the battery efficiency.
[0054] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.
Claims
1. A negative electrode electrolyte for an acid flow battery, characterized in that: The negative electrode electrolyte comprises an iron salt and a complexing agent, the molar concentration ratio of the complexing agent to the iron salt is 0.8 to 2.5, and the pH range of the negative electrode electrolyte is 1-4.
2. The negative electrode electrolyte according to claim 1, characterized in that The iron salts include ferrous chloride, ferrous sulfate, ferrous nitrate, ferric chloride, ferric sulfate, ferric oxyhydroxide and ferric nitrate.
3. The negative electrode electrolyte according to claim 1, characterized in that The complexing agent includes sodium tripolyphosphate, potassium tripolyphosphate, potassium pyrophosphate, sodium pyrophosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, sodium dihydrogen phosphate and potassium dihydrogen phosphate.
4. The negative electrode electrolyte according to claim 1, characterized in that The concentration of the iron salt ranges from 0.1 to 2.0 mol / L.
5. A method for preparing a negative electrolyte for an acidic liquid flow battery according to any one of claims 1 to 4, characterized in that: include: preparing a first solution containing an iron salt; preparing a second solution containing a complexing agent; Adjusting the pH of the second solution to 1-4; The second solution after adjusting the pH is gradually mixed with the first solution.
6. The method for preparing the negative electrode electrolyte according to claim 5, characterized in that: The step of gradually mixing the second solution after adjusting the pH with the first solution comprises: gradually adding the second solution to the first solution to obtain a mixed solution, and making the mixed solution to a preset volume with deionized water; The mixed solution is allowed to react at a preset temperature for a preset time to obtain the negative electrode electrolyte.
7. The method for preparing the negative electrode electrolyte according to claim 6, characterized in that: The preset temperature is 25°C to 95°C, and the preset time is 10 minutes to 24 hours.
8. The method for preparing the negative electrode electrolyte according to claim 5, characterized in that: The acid solution used to adjust the pH value of the second solution includes hydrochloric acid, phosphoric acid, sulfuric acid and nitric acid.
9. An acid flow battery, characterized in that: The acidic liquid flow battery comprises the negative electrode electrolyte according to any one of claims 1 to 4.
10. The acidic liquid flow battery according to claim 9, characterized in that The diaphragm of the acidic liquid flow battery is a perfluorosulfonic acid membrane or a porous membrane.