Aqueous zinc ion battery electrolyte and aqueous zinc ion battery

Abstract

The invention provides an aqueous zinc ion battery electrolyte and an aqueous zinc ion battery, the aqueous zinc ion battery electrolyte comprises pure water, soluble zinc ion salt and an additive, and the additive is 1-nitroso-2-naphthol-6-sodium sulfonate ferric salt. The 1-nitroso-2-naphthol-6-sulfonic acid group generated by ionization in the electrolyte can be directionally adsorbed on the surface of a zinc negative electrode, so that dendritic crystal growth and hydrogen evolution reaction on the surface of the negative electrode are inhibited; fe < 3 + > ions generated by ionization can be embedded into the positive electrode material in the battery circulation process, and the capacity of the battery is improved, so that the problem of capacity fading in the battery circulation process is solved, and the circulation stability of the battery is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage of aqueous zinc-ion batteries, and particularly relates to an electrolyte for an aqueous zinc-ion battery and an aqueous zinc-ion battery. Background Art

[0002] With the development of clean energy technologies such as wind energy, solar energy, and tidal energy, large-scale energy storage technologies have become increasingly important. In recent years, lithium-ion batteries have been widely used in portable electronic devices, electric vehicles, and large-scale energy storage fields due to their high energy density, long lifespan, and portability. However, the limited lithium resources and harsh assembly conditions have increased the cost of commercial lithium-ion batteries. At the same time, the organic electrolytes of lithium-ion batteries are toxic, flammable, and during the operation of lithium-ion batteries, irregular lithium dendrites can cause internal short circuits in lithium-ion batteries, leading to battery heating and explosion.

[0003] Compared with lithium-ion batteries based on organic electrolytes, aqueous metal-ion batteries represented by aqueous zinc-ion batteries have higher safety and lower costs, showing great application potential in the field of large-scale energy storage. As a typical anode material for zinc-ion batteries, metallic zinc has advantages such as high abundance, low toxicity, low price, and the ability to stably exist in air and electrolytes. In addition, the zinc anode also has a high theoretical capacity (820 mAh / g, 5855 mAh / cm3) and a low redox potential (-0.76 V vs. standard hydrogen electrode). These characteristics make aqueous zinc-ion batteries promising for future large-scale energy storage applications. However, in aqueous zinc-ion batteries, side reactions at the anode-electrolyte interface lead to anode corrosion and dendrite growth, seriously affecting the cycle life of aqueous zinc-ion batteries; in addition, cathode active materials represented by manganese dioxide are often affected by problems such as structural collapse and phase change during the battery cycle, resulting in a low battery capacity.

[0004] In order to solve the above problems, in recent years, relevant researchers have dealt with the side reactions at the zinc negative electrode-electrolyte interface through strategies such as negative electrode structure design, construction of interface layer on the negative electrode surface and electrolyte optimization. Among them, electrolyte additives have the advantages of low cost and simple operation, and have broad application prospects in realizing long-life aqueous zinc ion batteries. For example, patent CN119275383 A uses thiazole derivatives as additives to effectively isolate the negative electrode from the electrolyte, alleviating the interface side reactions; patent CN118017034 A uses aluminum nitrate as an electrolyte additive to construct an electrostatic shielding layer on the negative electrode surface, promoting the uniform deposition of zinc ions and inhibiting dendrite growth; for example, patent CN 118017032 A uses fluoroborate as an additive to regulate the solvation structure of zinc ions and reduce the active water molecules generated during the electroplating process, thereby inhibiting hydrogen evolution and corrosion and passivation of the zinc negative electrode and other side reactions. Although relevant personnel have made many efforts to improve the cycle performance of aqueous zinc-ion batteries based on electrolyte additives, they all focus on the interfacial reaction between the negative electrode and the electrolyte. The capacity attenuation problem caused by the collapse and phase change of the positive electrode material during the cycle still needs to be solved urgently. Summary of the invention

[0005] In view of this, the present invention aims to overcome the defects in the prior art and proposes an aqueous zinc ion battery electrolyte and an aqueous zinc ion battery. The 1-nitroso-2-naphthol-6-sulfonic acid group generated by ionization in the electrolyte of the present invention can be directionally adsorbed on the surface of the zinc negative electrode to inhibit the dendrite growth and hydrogen evolution reaction on the negative electrode surface; the Fe 3+ Ions can be embedded into the positive electrode material during the battery cycle, increasing the capacity of the battery, thereby solving the problem of capacity attenuation during the battery cycle and improving the battery's cycle stability.

[0006] To achieve the above object, the technical solution of the present invention is achieved as follows: In a first aspect, the present invention provides an aqueous zinc ion battery electrolyte, comprising pure water, a soluble zinc ion salt and an additive, wherein the additive is 1-nitroso-2-naphthol-6-sulfonic acid sodium iron salt (naphthol green B).

[0007] Preferably, the molar concentration of the naphthol green B in the electrolyte is 0.01-20 mmol / L.

[0008] More preferably, the molar concentration of naphthol green B in the electrolyte is 0.05 mmol / L.

[0009] Preferably, the soluble zinc ion salt is one or more of zinc sulfate, zinc acetate, zinc chloride, and zinc trifluoromethanesulfonate.

[0010] More preferably, the soluble zinc ion salt is zinc sulfate.

[0011] More preferably, the molar concentration of the soluble zinc ion salt is 1-3 mol / L.

[0012] Preferably, the preparation method of the aqueous zinc ion battery electrolyte comprises the following steps: adding a soluble zinc ion salt and an additive into pure water and dissolving them to obtain the aqueous zinc ion battery electrolyte.

[0013] In a second aspect, the present invention also provides an aqueous zinc ion battery using the above electrolyte.

[0014] Preferably, the aqueous zinc ion battery comprises a positive electrode, a negative electrode, a separator and the above electrolyte.

[0015] Compared with the prior art, the present invention has the following advantages: (1) In the present invention, sodium 1-nitroso-2-naphthol-6-sulfonate ferric salt is used as an additive in the aqueous zinc ion battery electrolyte. The additive can ionize in the electrolyte to generate 1-nitroso-2-naphthol-6-sulfonic acid group, which can be directionally adsorbed on the surface of the zinc negative electrode, so as to spontaneously form an interfacial layer containing the above groups on the negative electrode surface. This interfacial layer can isolate the direct contact between the electrolyte and the negative electrode and relieve the corrosion reaction of the negative electrode. In addition, since the group contains oxygen-containing functional groups such as phenolic hydroxyl groups, it can reduce the nucleation overpotential of zinc ions during the charging process of the battery and assist in inducing the uniform deposition of zinc, thereby inhibiting the growth of dendrites on the negative electrode surface.

[0016] (2) In the present invention, sodium 1-nitroso-2-naphthol-6-sulfonate ferric salt is used as an additive in the aqueous zinc ion battery electrolyte. The additive can also ionize in the electrolyte to generate Fe 3+ ions, which can spontaneously embed into the manganese dioxide positive electrode during the discharge process of the battery and will not escape from the active material during the charging process. This is beneficial to stabilizing the positive electrode structure. At the same time, the embedded Fe 3+ ions can increase the capacity of the battery, which is more conducive to realizing a stable long-life aqueous zinc ion battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a comparison diagram of the cycle life of the Zn‖Zn symmetric battery of Example 1 and Comparative Example 1, Comparative Example 2 and Comparative Example 3 of the present invention; Figure 2 It is a comparison diagram of the surface XRD of the Zn‖Zn symmetric battery of Example 1 and Comparative Example 1 of the present invention; Figure 3 It is the SEM photograph of the negative electrode of the Zn‖Zn symmetric battery of Example 1 and Comparative Example 1 of the present invention after constant current charge and discharge. (a) is Comparative Example 1, and (b) is Example 1; Figure 4Cycling life comparison chart of the Zn‖Cu half-cell assembled for Application Example 1 and Comparative Application Example 1 of the present invention; Figure 5 Cycling performance comparison chart of the aqueous zinc-ion full cell assembled for Application Example 2 and Comparative Application Example 2 of the present invention; Figure 6 XPS diagram of the positive electrode after 20 cycles of the aqueous zinc-ion full cell assembled in Example 3 of the present invention. Detailed implementation manners

[0018] The embodiments of the present invention will be described in detail below. The following described embodiments are exemplary and are only used to explain the present invention, and should not be construed as a limitation to the present invention.

[0019] In this article, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs.

[0020] In this article, when a value is described as a range, it should be understood that such disclosure includes the disclosure of all possible sub-ranges within that range, as well as specific numerical values falling within that range, regardless of whether specific numerical values or specific sub-ranges are explicitly indicated.

[0021] In this article, when referring to "multiple", etc., unless otherwise specified, it means greater than 2 or equal to 2 in quantity. For example, "one or more" means one or greater than or equal to two.

[0022] In this article, when referring to "preferred", "more preferred", it is only to describe embodiments or examples with better effects, and it should be understood that it does not constitute a limitation to the protection scope of the present invention.

[0023] In this article, when referring to "further", etc., for descriptive purposes, it indicates a difference in content, but should not be construed as a limitation to the protection scope of the present invention.

[0024] In this article, the term "and / or" is a description of the association relationship of an object, indicating that there can be three relationships. For example, A and / or B means: A or B, or the three relationships of A and B.

[0025] In this article, the term "about" means + / - 10% of the specified value, preferably + / - 5%, more preferably + / - 1%.

[0026] In this article, the terms "comprising", "including", "having", "containing", etc. are all open-ended terms, that is, they are intended to include but not limited to.

[0027] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although this invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of this invention.

[0028] The present invention will be described in detail below in conjunction with embodiments.

[0029] An aqueous zinc-ion battery electrolyte is composed of pure water, soluble zinc-ion salts, and an additive. The additive is sodium iron(III) 1-nitroso-2-naphthol-6-sulfonate (naphthol green B). Among them, the soluble zinc-ion salt is one or more of zinc sulfate, zinc acetate, zinc chloride, and zinc trifluoromethanesulfonate, and its molar concentration is 1 - 3 mol / L; the molar concentration of naphthol green B in the electrolyte is 0.01 - 20 mmol / L.

[0030] The aqueous zinc-ion battery electrolyte is prepared by the following steps: Under room temperature conditions, the soluble zinc-ion salt and the additive are added to pure water and dissolved to obtain the aqueous zinc-ion battery electrolyte.

[0031] The aqueous zinc-ion battery is prepared by the following steps: Step 1: Prepare the positive electrode active material. Potassium permanganate is dissolved in pure water, and concentrated hydrochloric acid is added dropwise while stirring. The above mixed solution is placed in a high-pressure reaction kettle, dried in a forced-air drying oven, the reaction solution is filtered, and the filter residue is washed repeatedly with pure water and absolute ethanol and then dried to obtain the manganese dioxide positive electrode active material.

[0032] Step 2: Prepare the positive electrode material. Using N-methylpyrrolidone as a solvent, the manganese dioxide active material, conductive carbon black, and polyvinylidene fluoride obtained in Step 1 are uniformly ground and mixed in an agate mortar. The obtained slurry is evenly coated on the current collector with a scraper and dried to obtain the positive electrode material.

[0033] Step 3: Cut into pieces. The zinc foil, copper foil, and the above positive electrode material are cut into circular pieces with a manual cutting machine; the glass fiber separator is cut into circular pieces.

[0034] Step 4: Assemble and seal with a small hydraulic button battery sealing machine in the order of negative electrode case, negative electrode sheet, glass fiber separator, electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode case.

[0035] It should be noted that a Zn‖Zn symmetric battery can be assembled with the above positive electrode sheet being a zinc sheet, and a Zn‖Cu half-cell can be assembled with the above positive electrode sheet being a copper sheet.

[0036] Example 1: At room temperature, 57.512 g of ZnSO4•7H2O and 0.0044 g of iron(III) 1-nitroso-2-naphthol-6-sulfonate are dissolved in pure water and made up to 100 mL with a volumetric flask to obtain the electrolyte for the aqueous zinc-ion battery, where the molar concentration of zinc sulfate is 2 mol / L and the molar concentration of iron(III) 1-nitroso-2-naphthol-6-sulfonate is 0.05 mmol / L.

[0037] The aqueous zinc-ion battery is prepared by the following steps: Step 1: Preparation of the positive electrode active material. 3.161 g of potassium permanganate is dissolved in 392.5 mL of pure water, and 7.5 mL of concentrated hydrochloric acid is added dropwise with stirring. The above mixed solution is placed in a high-pressure reaction kettle and heated in a blast drying oven at 160 °C for 12 h. Then, the reaction solution is filtered, and the filtrate is washed repeatedly with pure water and absolute ethanol and dried at 60 °C for 8 h to obtain the manganese dioxide positive electrode active material.

[0038] Step 2: Preparation of the positive electrode material. Using N-methylpyrrolidone as a solvent, the manganese dioxide active material, conductive carbon black, and polyvinylidene fluoride obtained in Step 1 are uniformly ground and mixed in an agate mortar according to a mass ratio of 7:2:1. Using a 30-μm zinc foil as the current collector, the obtained slurry is uniformly coated on the above current collector with a 150-mm scraper and dried at 60 °C for 2 h to obtain the positive electrode material.

[0039] Step 3: Cutting into pieces. The 30-μm zinc foil and the above positive electrode material are cut into circular pieces with a diameter of 15 mm using a manual cutting machine; the glass fiber separator is cut into circular pieces with a diameter of 20 mm.

[0040] Step 4: Assemble in the order of the negative electrode case, negative electrode sheet, glass fiber separator, electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode case using a small hydraulic button battery sealer under a pressure of 50 Mpa. A Zn‖Zn symmetric battery is prepared.

[0041] Example 2: At room temperature, 28.756 g of ZnSO4•7H2O and 0.00088 g of iron(III) 1-nitroso-2-naphthol-6-sulfonate are dissolved in pure water and made up to 100 mL with a volumetric flask to obtain the electrolyte for the aqueous zinc-ion battery, where the molar concentration of zinc sulfate is 1 mol / L and the molar concentration of iron(III) 1-nitroso-2-naphthol-6-sulfonate is 0.01 mmol / L. A Zn‖Zn symmetric battery is prepared according to the preparation steps of the aqueous zinc-ion battery in Example 1.

[0042] Example 3: At room temperature, 86.268 g of ZnSO4•7H2O and 1.76 g of iron(III) 1-nitroso-2-naphthol-6-sulfonate are dissolved in pure water and made up to 100 mL with a volumetric flask to obtain an aqueous zinc-ion battery electrolyte, where the molar concentration of zinc sulfate is 3 mol / L and the molar concentration of iron(III) 1-nitroso-2-naphthol-6-sulfonate is 20 mmol / L. A Zn‖Zn symmetric battery is prepared according to the preparation steps of the aqueous zinc-ion battery in Example 1.

[0043] Example 4: The preparation of the Zn‖Zn symmetric battery in this example is the same as that in Example 1, except that the soluble zinc ion salt is zinc acetate.

[0044] Example 5: The preparation of the Zn‖Zn symmetric battery in this example is the same as that in Example 1, except that the soluble zinc ion salt is zinc trifluoromethanesulfonate.

[0045] Example 6: The preparation of the Zn‖Zn symmetric battery in this example is the same as that in Example 1, except that the soluble zinc ion salt is zinc chloride.

[0046] Comparative Example 1: The difference from Example 1 is that iron(III) 1-nitroso-2-naphthol-6-sulfonate is not added.

[0047] Comparative Example 2: The difference from Example 1 is that the molar concentration of iron(III) 1-nitroso-2-naphthol-6-sulfonate is 0.005 mmol / L.

[0048] Comparative Example 3: The difference from Example 1 is that the molar concentration of iron(III) 1-nitroso-2-naphthol-6-sulfonate is 30 mmol / L.

[0049] Performance test: The Zn‖Zn symmetric batteries of Example 1 and Comparative Examples 1, 2, and 3 are subjected to performance tests, and galvanostatic charge-discharge tests are carried out at a current density of 1 mA cm -2 and an areal capacity of 1 mAh cm -2 .

[0050] As Figure 1Shown are the cycle time-voltage curves of the Zn‖Zn symmetric battery under the electrolyte systems of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3. It can be seen that after adding 0.005 mmol / L of iron(III) 1-nitroso-2-naphthol-6-sulfonate to the electrolyte, the cycle life of the Zn‖Zn symmetric battery shows no significant change, indicating that at this concentration, this additive has no significant effect on the battery life. When the molar concentration of iron(III) 1-nitroso-2-naphthol-6-sulfonate in the electrolyte is 30 mmol / L, the cycle life of the battery is about 800 h, indicating that although a high concentration of the additive can improve the battery life, the effect is not satisfactory. When the concentration of the additive is 0.05 mmol / L, the cycle life of the battery is extended to 3500 h, and the voltage fluctuation range is small, indicating that the addition of iron(III) 1-nitroso-2-naphthol-6-sulfonate can significantly improve the cycle life and cycle stability of the Zn‖Zn symmetric battery.

[0051] As Figure 2 Shown is the XRD pattern of the Zn‖Zn symmetric battery after 20 cycles under the electrolyte systems of Example 1 and Comparative Example 1. From Figure 2 it can be seen that before and after adding iron(III) 1-nitroso-2-naphthol-6-sulfonate to the electrolyte, the deposit on the negative electrode surface is zinc, without any other substances, especially the iron species in iron(III) 1-nitroso-2-naphthol-6-sulfonate.

[0052] As Figure 3 Shown is the SEM image of the Zn‖Zn symmetric battery after 20 cycles under the electrolyte systems of Example 1 and Comparative Example 1. From Figure 3 a, it can be seen that in the electrolyte without adding iron(III) 1-nitroso-2-naphthol-6-sulfonate (Comparative Example 1), a large number of dendrites are generated on the negative electrode surface of the Zn‖Zn symmetric battery after multiple cycles; from Figure 3 b, it can be seen that the negative electrode surface of the Zn‖Zn symmetric battery in the electrolyte system with the addition of iron(III) 1-nitroso-2-naphthol-6-sulfonate (Example 1) remains dense and uniform, indicating that iron(III) 1-nitroso-2-naphthol-6-sulfonate has a significant inhibitory effect on the dendrite growth of the negative electrode.

[0053] Application Example 1: At room temperature, 57.512 g of ZnSO4•7H2O and 0.0044 g of iron(III) 1-nitroso-2-naphthol-6-sulfonate are dissolved in pure water and made up to 100 mL with a volumetric flask to obtain an aqueous zinc-ion battery electrolyte, where the molar concentration of zinc sulfate is 2 mol / L and the molar concentration of iron(III) 1-nitroso-2-naphthol-6-sulfonate is 0.05 mmol / L. A Zn‖Cu half-cell is prepared according to the above preparation steps of the aqueous zinc-ion battery.

[0054] Comparative Application Example 1: The difference from Application Example 1 is that sodium iron(III) 1-nitroso-2-naphthol-6-sulfonate is not added.

[0055] Performance Test: The aqueous zinc-ion battery electrolytes in Application Example 1 and Comparative Application Example 1 were subjected to performance tests using a Zn‖Cu half-cell: The Zn‖Cu half-cell was placed in the electrolyte systems of Application Example 1 and Comparative Application Example 1 respectively, and a constant current charge-discharge test was carried out at a current density of 5 mA cm -2 and an areal capacity of 1 mAh cm -2 .

[0056] As Figure 4 shown in the cycle number-Coulomb efficiency graph of the Zn‖Cu half-cell under the electrolyte systems of Application Example 1 and Comparative Application Example 1, it can be seen from Figure 4 the graph that after adding sodium iron(III) 1-nitroso-2-naphthol-6-sulfonate to the electrolyte, the cycle number of the Zn‖Cu half-cell increased significantly from 229 cycles to 2500 cycles, and the Coulomb efficiency increased from 98.42% to 99.87%. This indicates that the addition of sodium iron(III) 1-nitroso-2-naphthol-6-sulfonate can significantly improve the cycle life and Coulomb efficiency of the Zn‖Cu half-cell.

[0057] Application Example 2: At room temperature, 57.512 g of ZnSO4•7H2O, 3.3802 g of manganese(II) sulfate monohydrate and 0.0044 g of sodium iron(III) 1-nitroso-2-naphthol-6-sulfonate were dissolved in pure water and made up to 100 mL with a volumetric flask to obtain an aqueous zinc-ion battery electrolyte, where the molar concentration of zinc sulfate was 2 mol / L, the concentration of manganese(II) sulfate was 0.2 mol / L, and the molar concentration of sodium iron(III) 1-nitroso-2-naphthol-6-sulfonate was 0.05 mmol / L. A Zn-MnO2 full cell was prepared according to the above preparation steps of the aqueous zinc-ion battery.

[0058] Comparative Application Example 2: The difference from Application Example 2 is that sodium iron(III) 1-nitroso-2-naphthol-6-sulfonate is not added.

[0059] Performance Test: The aqueous zinc-ion battery electrolytes in Application Example 2 and Comparative Application Example 2 were subjected to performance tests using a Zn-MnO2 full cell: The Zn-MnO2 full cell was placed in the electrolyte systems of Application Example 2 and Comparative Application Example 2 respectively, and a constant current charge-discharge test was carried out at a current density of 0.2 A / g.

[0060] As Figure 5Cycling performance comparison chart of the assembled aqueous zinc-ion full battery under the electrolyte systems of Application Example 2 and Comparative Application Example 2. It can be seen from Figure 5 that after 250 cycles of testing, the specific capacity of the battery in Comparative Application Example 2 decreased to 60 mAh / g, while the specific capacity of the battery in Application Example 2 increased to 373 mAh / g, indicating that the addition of sodium 1-nitroso-2-naphthol-6-sulfonate iron salt can significantly improve the battery capacity.

[0061] As Figure 6 shown, in the XPS diagram of the positive electrode of the aqueous zinc-ion battery after 20 cycles under the electrolyte system of Application Example 2, an obvious Fe 2p peak was observed, indicating that Fe 3+ ions ionized from sodium 1-nitroso-2-naphthol-6-sulfonate iron salt during the cycling process can enter the active material inside the positive electrode, thus improving the battery capacity.

[0062] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An aqueous zinc-ion battery electrolyte, characterized in that: It includes pure water, soluble zinc ion salt and an additive, and the additive is iron(III) 1-nitroso-2-naphthol-6-sulfonate.

2. The aqueous zinc-ion battery electrolyte according to claim 1, wherein: The molar concentration of the iron(III) 1-nitroso-2-naphthol-6-sulfonate in the electrolyte is 0.01 - 20 mmol / L.

3. The aqueous zinc-ion battery electrolyte according to claim 1, wherein: The molar concentration of the iron(III) 1-nitroso-2-naphthol-6-sulfonate in the electrolyte is 0.05 mmol / L.

4. The aqueous zinc ion battery electrolyte according to claim 1, characterized in that: The soluble zinc ion salt is one or more of zinc sulfate, zinc acetate, zinc chloride, and zinc trifluoromethanesulfonate.

5. The aqueous zinc ion battery electrolyte according to claim 1, characterized in that: The soluble zinc ion salt is zinc sulfate.

6. The aqueous zinc-ion battery electrolyte according to claim 1, wherein: The molar concentration of the soluble zinc ion salt is 1 - 3 mol / L.

7. The aqueous zinc ion battery electrolyte according to claim 1, characterized in that: The preparation method of the aqueous zinc ion battery electrolyte includes the following steps: adding the soluble zinc ion salt and the additive into pure water and dissolving them to obtain the aqueous zinc ion battery electrolyte.

8. An aqueous zinc ion battery using the electrolyte according to any one of claims 1 - 7.

9. The aqueous zinc ion battery according to claim 8, wherein: The aqueous zinc ion battery includes a positive electrode, a negative electrode, a separator, and the electrolyte according to any one of claims 1 - 7.

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