Electrolyte system for in-situ repair of zinc negative electrode alloy interface and preparation method thereof

Abstract

The invention provides an electrolyte system for in-situ repair of a zinc negative electrode alloy interface and a preparation method of the electrolyte system, and belongs to the technical field of zinc metal batteries. The diaphragm loaded with the indissolvable copper-based compound is matched with the zinc salt electrolyte with the function of slowly dissolving the copper-based compound, so that the dynamic balance of low-concentration copper ions in an electrolyte system is realized. The mixed electrolyte system can promote the zinc negative electrode to generate continuous and slow in-situ zinc / copper replacement and promote spontaneous alloying in battery circulation, so that a zinc / copper alloy layer on a zinc negative electrode interface can be continuously repaired, the circulation stability of the zinc metal battery is remarkably improved, and the service life of the zinc metal battery is remarkably prolonged. The electrolyte system for in-situ repair of the zinc negative electrode alloy interface is simple in preparation process and low in production cost, and has industrial production prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of zinc metal batteries, and in particular to an electrolyte system for in-situ repairing a zinc negative electrode alloy interface and a preparation method thereof. Background Art

[0002] Zinc metal batteries, due to their high theoretical capacity (820 mAh / g), low cost, and environmentally friendly properties, are considered an ideal candidate for large-scale stationary energy storage, particularly in grid-level energy storage, to address the intermittent and volatile nature of renewable energy. However, zinc anodes are susceptible to hydrogen evolution reactions, metal corrosion, and dendrite growth during cycling, leading to reduced coulombic efficiency and internal short circuits, severely restricting their practical application. Existing improvement strategies generally face challenges such as complex processes, high costs, or interfacial failure after long-term cycling.

[0003] Zinc has a low nucleation barrier on the copper surface, effectively regulating zinc deposition. However, during long-term cycling, the zinc / copper alloy interface cannot participate in the stripping process due to the high standard electrode potential of copper (E = +0.337 V). As a result, the alloy layer is gradually covered by deposits and byproducts, leading to early failure of the zinc-philic interface.

[0004] The electrolyte is crucial in stabilizing electrodes and ensuring electrochemical performance. Chinese patent CN119852565A discloses an electrolyte containing a metal ligand complex, such as a Cu-EDTA complex. This patent, by adding the complex as an additive to the aqueous zinc-ion battery electrolyte, alleviates the dendrite, corrosion, hydrogen evolution, and passivation problems of the zinc negative electrode to a certain extent. A Zn / / Zn symmetric battery based on this electrolyte exhibits excellent performance at a current density of 4 mA cm -2 , deposition capacity of 4 mAhcm -2 Under the condition of , the cycle life is more than 1250 h. 2+ The dissociation of the Cu-EDTA complex will quickly replace the metal zinc electrode, making it almost equivalent to using a copper-plated zinc anode. However, this static coating is easily covered or even degraded during long-term cycling, and cannot play a long-term regulatory role in zinc deposition, which limits the effect of the Cu-EDTA complex on improving the cycling stability of zinc-ion batteries.

[0005] Based on this, the present invention develops a method capable of continuously releasing Cu 2+ The ions can then dynamically update and repair the electrolyte system of the alloy interface to solve the problem of long-cycle stability of the zinc negative electrode and promote the practical application of zinc metal batteries. Summary of the Invention

[0006] In response to the above-mentioned deficiencies in the prior art, the present invention provides an electrolyte system for in-situ repairing the zinc negative electrode alloy interface and a preparation method thereof. The application of the electrolyte system in zinc metal batteries can significantly improve the service life of zinc metal batteries. In addition, the preparation method uses cheap materials, has a simple process, is easy to implement, and is conducive to large-scale production.

[0007] To achieve the above purpose, the specific technical solutions of the present invention are as follows:

[0008] The present invention provides an electrolyte system for in-situ repairing the interface of a zinc negative electrode alloy, comprising: a diaphragm and a zinc salt electrolyte, wherein the diaphragm is loaded with an insoluble copper-based compound, and the zinc salt electrolyte has the function of slowly dissolving the copper-based compound; in the electrolyte system, the zinc salt electrolyte drives the copper-based compound to dissolve through complexation and continuously releases copper ions (Cu 2+ ), so that the concentration of copper ions in the electrolyte system is maintained in a low concentration dynamic equilibrium state for a long time.

[0009] The present invention is to dissolve Cu 2+ The functional zinc salt electrolyte is combined with a diaphragm loaded with an insoluble copper-based compound to construct a copper ion slow-release electrolyte system with dynamic equilibrium. Under the complexation effect, the insoluble copper-based compound stably releases low-concentration copper ions through continuous complexation and dissolution, so that the concentration of copper ions in the electrolyte system is maintained at a low-concentration dynamic equilibrium state. This design of the present invention not only enables the copper ions in the electrolyte system to undergo a continuous and slow in-situ replacement reaction with the zinc negative electrode, but also promotes the spontaneous formation of zinc-copper alloys during the battery cycle. By continuously repairing the alloy layer at the zinc negative electrode interface, it ensures that the zinc-copper alloy sites always maintain surface activity and structural integrity during the cycle, thereby effectively solving the interface failure problem caused by long-term circulation, and ultimately significantly inhibiting the growth of zinc dendrites, so that the cycle stability and service life of zinc-based batteries are significantly improved.

[0010] Furthermore, the separator has a three-layer structure, comprising a layer of glass fiber paper loaded with a poorly soluble copper-based compound and two layers of unloaded glass fiber paper (i.e., ordinary glass fiber paper). Placing the glass fiber paper loaded with the poorly soluble copper-based compound in the middle layer of the three-layer separator prevents the poorly soluble copper-based compound from coming into direct contact with the zinc electrode, which could cause uncontrolled reduction reactions.

[0011] Furthermore, the insoluble copper-based compound includes copper hydroxide and / or basic copper salt.

[0012] Furthermore, the basic copper salt includes but is not limited to at least one of basic copper chloride, basic copper sulfate, basic copper carbonate, and basic copper nitrate.

[0013] Furthermore, when the insoluble copper-based compound is copper hydroxide, the method for preparing the diaphragm comprises the following steps:

[0014] The copper hydroxide and excess ammonia water are mixed uniformly and then centrifuged, the supernatant is collected, and the supernatant is added dropwise to glass fiber paper, and dried to obtain glass fiber paper loaded with copper hydroxide; the glass fiber paper loaded with copper hydroxide is used as the middle layer, and unloaded glass fiber paper is used as the two side layers to construct a three-layer structured diaphragm;

[0015] When the insoluble copper-based compound is a basic copper salt, the method for preparing the diaphragm comprises the following steps:

[0016] The copper salt is mixed evenly with excess ammonia water to obtain a copper-ammonia complex solution; the copper-ammonia complex solution is added dropwise to glass fiber paper and dried to obtain glass fiber paper loaded with basic copper salt; the glass fiber paper loaded with basic copper salt is used as the middle layer and unloaded glass fiber paper is used as the two side layers to construct a diaphragm with a three-layer structure.

[0017] Furthermore, in the glass fiber paper loaded with copper hydroxide, the copper hydroxide loading amount is 3-6 mg / cm 2 .

[0018] Furthermore, in the glass fiber paper loaded with basic copper salt, the basic copper salt loading amount is 5-15 mg / cm 2 .

[0019] Specifically, when the insoluble copper-based compound is copper hydroxide, the preparation method of the diaphragm comprises the following steps: dissolving 5-10 g of copper hydroxide in 40-100 mL of ammonia water, stirring at room temperature for 30 minutes, and centrifuging to extract a blue supernatant; dropping 80-150 μl of the supernatant onto a glass fiber paper with a diameter of 1.6 cm and a thickness of 200 μm, and drying it in an oven at 55°C; after taking it out, dropping 80-170 μl of the supernatant on the other side, and also drying it at 55°C; repeating the process 2-4 times on both sides to obtain a copper hydroxide loading of 3-6 mg / cm 2 with the glass fiber paper loaded with copper hydroxide as the middle layer, and unloaded glass fiber paper as the two side layers, to construct a diaphragm having a three-layer structure.

[0020] Specifically, when the insoluble copper-based compound is a basic copper salt, the preparation method of the diaphragm comprises the following steps: dissolving 5 to 20 g of copper salt in 20 to 40 mL of ammonia water to generate a dark blue transparent copper-ammonia complex solution; dropping 80 to 150 microliters of the copper-ammonia complex solution into a glass fiber paper with a diameter of 1.6 cm and a thickness of 200 microns, and drying it in a 55°C oven; after taking it out, dripping the copper-ammonia complex solution on the other side, and also drying it at 55°C to obtain a basic copper salt loading of 5 to 15 mg / cm 2 with the glass fiber paper loaded with basic copper salt as the middle layer, and unloaded glass fiber paper as the two side layers, to construct a diaphragm having a three-layer structure.

[0021] Furthermore, the zinc salt electrolyte includes: zinc salt and solvent.

[0022] Furthermore, the zinc salt includes but is not limited to at least one of zinc chloride, zinc sulfate, zinc bromide, and zinc acetate.

[0023] Furthermore, in a water-based non-zinc chloride electrolyte (i.e., when the zinc salt is not zinc chloride), the zinc salt electrolyte also includes an additive capable of complexing and dissolving copper ions. When the zinc salt is zinc chloride, the high concentration of Cl ions can act as a complexing agent for complexing and dissolving copper ions, thus eliminating the need for an additional additive capable of complexing and dissolving copper ions.

[0024] Furthermore, in the zinc salt electrolyte, the concentration of zinc salt is 1-3 mol / L.

[0025] Furthermore, the solvent includes but is not limited to at least one of ethanol, methanol, ethylene glycol, and water.

[0026] Furthermore, the additive having the function of complexing and dissolving copper ions includes ethylenediaminetetraacetic acid (EDTA) salt.

[0027] Furthermore, the EDTA salt includes but is not limited to at least one of disodium EDTA, tetrasodium EDTA, sodium iron EDTA, sodium magnesium EDTA, and potassium EDTA.

[0028] Furthermore, in the zinc salt electrolyte, the concentration of the additive having the function of complexing and dissolving copper ions is 0.3-0.6 mol / L.

[0029] The present invention also provides application of the electrolyte system for in-situ repairing the zinc negative electrode alloy interface in zinc metal batteries.

[0030] The present invention also provides a zinc metal battery, comprising a zinc metal electrode and the electrolyte system for in-situ repairing the zinc negative electrode alloy interface.

[0031] Compared with the prior art, the present invention is beneficial in that:

[0032] (1) The zinc metal battery based on the electrolyte system for in-situ repair of the zinc negative electrode alloy interface of the present invention can achieve in-situ zinc-copper co-deposition, continuously renew the zinc-copper alloy sites on the zinc negative surface, help to regulate zinc deposition in the long term, inhibit the formation and growth of zinc dendrites, and significantly improve the cycle stability and service life of the zinc metal battery.

[0033] (2) The diaphragm in the electrolyte system for in-situ repairing the zinc negative electrode alloy interface of the present invention has a simple preparation process. The amount of supernatant is adjusted according to the volume of the diaphragm. Glass fiber diaphragms loaded with copper hydroxide or basic copper salt can be produced in large quantities at one time. The production cost is low and has industrial production prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The cycling performance test results of the Zn||Zn symmetrical battery prepared in Example 1 are shown;

[0035] Figure 2 The cycling performance test results of the Zn||Zn symmetrical battery prepared in Example 2;

[0036] Figure 3 The cycling performance test results of the Zn||Zn symmetrical battery prepared in Example 3;

[0037] Figure 4 The cycling performance test results of the Zn||Zn symmetrical battery prepared in Example 4;

[0038] Figure 5 The cycling performance test results of the Zn||Zn symmetrical battery prepared in Comparative Example 1 are shown;

[0039] Figure 6 The cycling performance test results of the Zn||Zn symmetrical battery prepared in Comparative Example 2 are shown;

[0040] Figure 7 Characterization results of the zinc electrodes of the Zn||Zn symmetrical battery of Example 1 after cycling for 400 hours and the comparative examples 1-2 after cycling to short-circuit failure;

[0041] Figure 8 8a is the characterization result of the copper hydroxide-loaded diaphragm after 3000 cycles of the Zn||Zn symmetric battery of Example 1; wherein, 8a is the characterization result of the copper hydroxide-loaded diaphragm at the beginning; 8b is the characterization result of the copper hydroxide-loaded diaphragm after 3000 cycles;

[0042] Figure 9 The concentration of soluble copper species is measured by mixing excess copper hydroxide into zinc chloride ethanol solutions of different concentrations;

[0043] Figure 10 CV curve test results of asymmetric Ti||Zn batteries assembled using the electrolyte systems of Example 1 and Comparative Example 2, respectively. DETAILED DESCRIPTION

[0044] The technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0045] The present invention provides an electrolyte system for in-situ repairing the interface of a zinc negative electrode alloy, comprising: a diaphragm and a zinc salt electrolyte, wherein the diaphragm is loaded with an insoluble copper-based compound, and the zinc salt electrolyte has the function of slowly dissolving the copper-based compound; in the electrolyte system, the zinc salt electrolyte drives the copper-based compound to dissolve through complexation and continuously releases copper ions (Cu 2+ ), so that the concentration of copper ions in the electrolyte system is maintained in a low concentration dynamic equilibrium state for a long time.

[0046] In some examples, the insoluble copper-based compound includes copper hydroxide and / or a basic copper salt, wherein the basic copper salt includes but is not limited to at least one of basic copper chloride, basic copper sulfate, basic copper carbonate, and basic copper nitrate.

[0047] In some examples, the zinc salt electrolyte includes: a zinc salt and a solvent, wherein the zinc salt includes but is not limited to at least one of zinc chloride, zinc sulfate, zinc bromide, and zinc acetate; and the solvent includes but is not limited to at least one of ethanol, methanol, ethylene glycol, and water.

[0048] In some examples, in a water-based non-zinc chloride electrolyte (i.e., when the zinc salt is not zinc chloride), the zinc salt electrolyte further includes an additive capable of complexing and solubilizing copper ions. The additive capable of complexing and solubilizing copper ions includes an ethylenediaminetetraacetic acid (EDTA) salt, including but not limited to at least one of disodium EDTA, tetrasodium EDTA, sodium ferric EDTA, sodium magnesium EDTA, and potassium EDTA.

[0049] In some examples, the concentration of zinc salt in the zinc salt electrolyte is 1-3 mol / L.

[0050] In some examples, the concentration of the additive having the function of complexing and dissolving copper ions in the zinc salt electrolyte is 0.3-0.6 mol / L.

[0051] Example 1

[0052] A zinc metal battery

[0053] Step S1, preparing a diaphragm:

[0054] Mix 5 g of copper hydroxide powder into 40 mL of ammonia water, stir at room temperature for 30 minutes, and centrifuge to extract the blue supernatant. Drop 120 μL of the supernatant onto a glass fiber paper with a diameter of 1.6 cm and a thickness of 200 μm, and dry it in a 55°C oven. Remove the glass fiber paper and drop 120 μL of the supernatant onto the other side, and also dry it at 55°C. Repeat this process three times on both the front and back sides to obtain a copper hydroxide loading of 5 mg / cm 2 with the glass fiber paper loaded with copper hydroxide as the middle layer, and unloaded glass fiber paper as the two side layers, to assemble a membrane having a three-layer structure.

[0055] Step S2, preparing a zinc salt electrolyte:

[0056] Weigh 5.46 g of anhydrous zinc chloride and place it in a container. Add anhydrous ethanol to make the total volume reach 20 mL. Stir at room temperature for 20 minutes to obtain a transparent ethanol zinc chloride solution.

[0057] Step S3, assembling the zinc metal battery:

[0058] A Zn||Zn symmetric battery was obtained by assembling a three-layer separator, ethanolic zinc chloride solution and commercial zinc foil.

[0059] Example 2

[0060] A zinc metal battery

[0061] Step S1, preparing a diaphragm:

[0062] Dissolve 10 g of copper chloride dihydrate in 20 mL of ammonia water and stir at room temperature for 30 minutes to obtain a dark blue transparent copper-ammonia complex solution. Take 100 μL of the copper-ammonia complex solution and drop it onto a glass fiber paper with a diameter of 1.6 cm and a thickness of 200 μm. Dry it in an oven at 55°C. Take out the glass fiber paper and drop 100 μL of the copper-ammonia complex solution onto the other side. Dry it at 55°C as well to obtain a basic copper chloride loading of 8.5 mg / cm 2 with the glass fiber paper loaded with basic copper chloride as the middle layer, and unloaded glass fiber paper as the two side layers, and the diaphragm having a three-layer structure was assembled.

[0063] Step S2, preparing a zinc salt electrolyte:

[0064] Weigh 5.46 g of anhydrous zinc chloride and place it in a container. Add anhydrous ethanol to make the total volume reach 20 mL. Stir at room temperature for 20 minutes to obtain a transparent ethanol zinc chloride solution.

[0065] Step S3, assembling the zinc metal battery:

[0066] A Zn||Zn symmetric battery was obtained by assembling a three-layer separator, ethanolic zinc chloride solution and commercial zinc foil.

[0067] Example 3

[0068] A zinc metal battery

[0069] Step S1, preparing a diaphragm:

[0070] Mix 5 g of copper hydroxide powder into 40 mL of ammonia water, stir at room temperature for 30 minutes, and centrifuge to extract the blue supernatant. Drop 120 μL of the supernatant onto a glass fiber paper with a diameter of 1.6 cm and a thickness of 200 μm, and dry it in a 55°C oven. Remove the glass fiber paper and drop 120 μL of the supernatant onto the other side, and also dry it at 55°C. Repeat this process three times on both the front and back sides to obtain a copper hydroxide loading of 5 mg / cm 2 with the glass fiber paper loaded with copper hydroxide as the middle layer, and unloaded glass fiber paper as the two side layers, to assemble a membrane having a three-layer structure.

[0071] Step S2, preparing a zinc salt electrolyte:

[0072] Weigh 8.18 g of anhydrous zinc chloride and place it in a container. Add deionized water to make the total volume reach 18 mL. Add 2 mL of methanol and stir at room temperature for 20 minutes to obtain a transparent water-based zinc chloride solution.

[0073] Step S3, assembling the zinc metal battery:

[0074] A Zn||Zn symmetric battery was obtained by assembling a separator with a three-layer structure, a water-based zinc chloride solution, and commercial zinc foil.

[0075] Example 4

[0076] A zinc metal battery

[0077] Step S1, preparing a diaphragm:

[0078] Mix 5 g of copper hydroxide powder into 40 mL of ammonia water, stir at room temperature for 30 minutes, and centrifuge to extract the blue supernatant. Drop 120 μL of the supernatant onto a glass fiber paper with a diameter of 1.6 cm and a thickness of 200 μm, and dry it in a 55°C oven. Remove the glass fiber paper and drop 120 μL of the supernatant onto the other side, and also dry it at 55°C. Repeat this process three times on both the front and back sides to obtain a copper hydroxide loading of 5 mg / cm 2with the glass fiber paper loaded with copper hydroxide as the middle layer, and unloaded glass fiber paper as the two side layers, to assemble a membrane having a three-layer structure.

[0079] Step S2, preparing a zinc salt electrolyte:

[0080] Weigh 11.5 g of zinc sulfate heptahydrate into a container, add deionized water to make the total volume reach 20 mL, add 3 g of disodium ethylenediaminetetraacetic acid, and stir at room temperature for 20 minutes to obtain a transparent water-based EDTA salt complexing agent zinc sulfate solution.

[0081] Step S3, assembling the zinc metal battery:

[0082] A Zn||Zn symmetric battery was assembled by assembling a three-layer separator, a water-based EDTA salt complexing agent zinc sulfate solution, and commercial zinc foil.

[0083] Comparative Example 1

[0084] A zinc metal battery

[0085] Step S1, preparing a diaphragm:

[0086] Mix 5 g of copper hydroxide powder into 40 mL of ammonia water, stir at room temperature for 30 minutes, and centrifuge to extract the blue supernatant. Drop 120 μL of the supernatant onto a glass fiber paper with a diameter of 1.6 cm and a thickness of 200 μm, and dry it in a 55°C oven. Remove the glass fiber paper and drop 120 μL of the supernatant onto the other side, and also dry it at 55°C. Repeat this process three times on both the front and back sides to obtain a copper hydroxide loading of 5 mg / cm 2 with the glass fiber paper loaded with copper hydroxide as the middle layer, and unloaded glass fiber paper as the two side layers, to assemble a membrane having a three-layer structure.

[0087] Step S2, preparing a zinc salt electrolyte:

[0088] Weigh 11.5 g of zinc sulfate heptahydrate into a container, add deionized water to make the total volume reach 20 mL, and obtain a transparent water-based zinc sulfate solution.

[0089] Step S3, assembling the zinc metal battery:

[0090] A Zn||Zn symmetric battery was assembled by assembling a three-layer separator, an aqueous zinc sulfate solution, and commercial zinc foil.

[0091] Comparative Example 2

[0092] A zinc metal battery

[0093] Step S1, preparing a diaphragm:

[0094] Unloaded glass fiber paper was used as the middle layer and both side layers to assemble a three-layer structured separator (without copper-based compound loading).

[0095] Step S2, preparing a zinc salt electrolyte:

[0096] Weigh 11.5 g of zinc sulfate heptahydrate into a container, add deionized water to make the total volume reach 20 mL, and obtain a transparent water-based zinc sulfate solution.

[0097] Step S3, assembling the zinc metal battery:

[0098] A Zn||Zn symmetric battery was assembled by assembling a three-layer separator, an aqueous zinc sulfate solution, and commercial zinc foil.

[0099] The Zn||Zn symmetrical cells assembled from Examples 1-4 and Comparative Examples 1-2 were tested at 1 mA cm -2 (1 mAh cm -2 ) to test the cycle life and cycle stability, the test results are as follows Figure 1-6 and as shown in Table 1.

[0100] Table 1: Cycling performance test results of Zn||Zn symmetric battery

[0101]

[0102] The experimental results show that the Zn||Zn symmetrical battery prepared in Example 1 can stably cycle for more than 3000 h, the Zn||Zn symmetrical battery prepared in Example 2 can stably cycle for more than 1620 h, the Zn||Zn symmetrical battery prepared in Example 3 can stably cycle for more than 1340 h, and the Zn||Zn symmetrical battery prepared in Example 4 can stably cycle for more than 2350 h, which is far superior to the Zn||Zn symmetrical battery that cannot continuously generate Cu by complexation. 2+ ions Zn||Zn symmetric battery (Comparative Example 1) and a Zn||Zn symmetric battery with a traditional water-based zinc sulfate electrolyte system (Comparative Example 2). The cycle life of the Zn||Zn symmetric batteries of Comparative Example 1 and Comparative Example 2 is less than 200 h.

[0103] The Zn||Zn symmetrical battery of Example 1 after 400 hours of cycling and the Zn||Zn symmetrical battery of Comparative Example 1-2 after cycling to short circuit failure were disassembled, and the zinc electrodes were characterized. Figure 7As shown in the figure, after 400 hours of circulation in the electrolyte system of Example 1, the zinc deposits on the zinc electrode surface are flat and dense, similar to the deposition morphology dominated by the Zn (002) crystal orientation. In contrast, the zinc deposits on the zinc electrode surfaces of Comparative Examples 1-2 are needle-shaped and flake-shaped, with irregular orientations. This structural morphology easily induces local electric field enhancement, accelerates local deposition, and further leads to dendrite formation and growth, seriously shortening the cycle life of zinc metal batteries.

[0104] The Zn||Zn symmetrical battery after 3000 cycles in Example 1 was disassembled and the copper hydroxide loaded diaphragm was characterized. The results are as follows: Figure 8 As shown in the figure, after the Zn||Zn symmetric battery of Example 1 was cycled for 3000 times, copper hydroxide particles were still present on the surface of the diaphragm. In order to verify that the zinc salt electrolyte of the present invention has the function of complexing and driving the dissolution of insoluble copper-based compounds, the inventors added copper hydroxide powder to zinc chloride ethanol solutions of different concentrations, mixed them evenly, and tested the concentration of soluble copper species in the solution. The results are shown in the figure. Figure 9 As shown in the figure, the concentration of soluble copper species increases with the increase of zinc chloride concentration, but always maintains a low concentration state. The above results indicate that the insoluble copper-based compound loaded in the diaphragm of the present invention can be dissolved by continuous complexation and stably release low-concentration copper ions, so that the concentration of copper ions in the electrolyte system is maintained at a low-concentration dynamic equilibrium state, achieving the function of continuously modifying the zinc electrode, thereby making the zinc metal battery of the present invention have excellent long-term cycle stability.

[0105] The electrolyte system of Example 1 and Comparative Example 2 was used to assemble an asymmetric Ti||Zn battery, and the CV curve test of the asymmetric Ti||Zn battery was performed. The results are as follows Figure 10 The figure shows that during the negative scan process (above 0 V), the asymmetric Ti||Zn battery assembled with the electrolyte system of Example 1 has a current response that is one order of magnitude higher than that of the asymmetric Ti||Zn battery assembled with the electrolyte system of Comparative Example 2, which reflects the low concentration of Cu 2+ It can promote a continuous and slow in-situ zinc / copper replacement at the zinc negative electrode and promote the spontaneous alloying process during battery cycling.

[0106] In summary, the present invention innovatively uses a diaphragm loaded with a sparingly soluble copper-based compound and a zinc salt electrolyte (or a zinc salt electrolyte containing a complexing agent for complexing and dissolving copper ions) with the function of slowly dissolving the copper-based compound to achieve a low concentration of Cu in the electrolyte system. 2+This mixed electrolyte system can promote a continuous and slow in-situ zinc / copper replacement at the zinc anode and promote spontaneous alloying during battery cycling, allowing the zinc / copper alloy layer at the zinc anode interface to be continuously repaired, providing new ideas for the development of long-life zinc metal batteries.

[0107] The above specific embodiments describe the implementation of the present invention in detail, but the present invention is not limited to the specific details of the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

Claims

1. An electrolyte system for in-situ repair of zinc negative electrode alloy interface, characterized in that: include: A diaphragm and a zinc salt electrolyte, wherein the diaphragm is loaded with an insoluble copper-based compound, and the zinc salt electrolyte has the function of slowly dissolving the copper-based compound; In the electrolyte system, the zinc salt electrolyte drives the copper-based compound to dissolve and continuously release copper ions through complexation, so that the concentration of copper ions in the electrolyte system is maintained in a low-concentration dynamic equilibrium state for a long time.

2. The electrolyte system for in-situ repair of zinc negative electrode alloy interface according to claim 1, characterized in that: The diaphragm has a three-layer structure, comprising a layer of glass fiber paper loaded with an insoluble copper-based compound and two layers of unloaded glass fiber paper.

3. The electrolyte system for in-situ repair of zinc negative electrode alloy interface according to claim 1, characterized in that: The insoluble copper-based compound includes copper hydroxide and / or basic copper salt.

4. The electrolyte system for in-situ repair of zinc negative electrode alloy interface according to claim 3, characterized in that: When the insoluble copper-based compound is copper hydroxide, the method for preparing the diaphragm comprises the following steps: The copper hydroxide and excess ammonia water are mixed uniformly and then centrifuged, the supernatant is collected, and the supernatant is added dropwise to glass fiber paper, and dried to obtain glass fiber paper loaded with copper hydroxide; the glass fiber paper loaded with copper hydroxide is used as the middle layer, and unloaded glass fiber paper is used as the two side layers to construct a three-layer structured diaphragm; When the insoluble copper-based compound is a basic copper salt, the method for preparing the diaphragm comprises the following steps: The copper salt is mixed evenly with excess ammonia water to obtain a copper-ammonia complex solution; the copper-ammonia complex solution is added dropwise to glass fiber paper and dried to obtain glass fiber paper loaded with basic copper salt; the glass fiber paper loaded with basic copper salt is used as the middle layer and unloaded glass fiber paper is used as the two side layers to construct a diaphragm with a three-layer structure.

5. The electrolyte system for in-situ repair of zinc negative electrode alloy interface according to claim 4, characterized in that: The glass fiber paper loaded with copper hydroxide has a copper hydroxide loading of 3-6 mg / cm 2 The glass fiber paper loaded with basic copper salt has a basic copper salt loading of 5 to 15 mg / cm 2 .

6. The electrolyte system for in-situ repair of zinc negative electrode alloy interface according to claim 1, characterized in that: The zinc salt electrolyte includes: zinc salt and solvent.

7. The electrolyte system for in-situ repair of zinc negative electrode alloy interface according to claim 6, characterized in that: When the zinc salt is not zinc chloride, the zinc salt electrolyte further comprises an additive having the function of complexing and dissolving copper ions.

8. The electrolyte system for in-situ repair of zinc negative electrode alloy interface according to claim 7, characterized in that: The additive having the function of complexing and dissolving copper ions includes ethylenediaminetetraacetate.

9. Use of the electrolyte system for in-situ repairing the zinc negative electrode alloy interface according to any one of claims 1 to 8 in zinc metal batteries.

10. A zinc metal battery, characterized in that: The invention relates to an electrolyte system comprising a zinc metal electrode and the in-situ repairing zinc negative electrode alloy interface according to any one of claims 1 to 8.

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