Preparation method and application of aqueous zinc ion battery negative electrode coating material

Abstract

The invention belongs to the technical field of aqueous zinc ion batteries, and discloses a preparation method and application of an aqueous zinc ion battery negative electrode coating material. The composite material is a silver-loaded carbon nitride composite material, and the composite material is used as a water-based zinc ion battery negative electrode artificial interface layer. A silver-loaded carbon nitride composite nano material is used as a zinc negative electrode interface coating. Silver nano ions can effectively improve electrostatic shielding on the surface of the zinc negative electrode, zinc ions are easier to deposit, and growth of zinc dendrites is inhibited; the material has excellent mechanical strength and chemical stability, so that the corrosion of electrolyte to the negative electrode is effectively inhibited; the protective layer is simple in preparation process, the prepared coating is high in adhesive force, a stable interface layer is easy to form, the half-cell cycle efficiency stability is obviously improved, the half-cell can stably circulate for 1323 circles, and the service life of the water-based zinc ion battery is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of aqueous zinc ion battery negative electrodes, and relates to a preparation method and application of an aqueous zinc ion battery negative electrode coating material. Background Art

[0002] The use of fossil fuels and the resulting environmental pollution make it crucial to prioritize the development of clean energy. Although solar or wind energy can provide intermittent energy, it cannot be used to operate traditional electronic devices. Therefore, academia and industry have been paying close attention to the development of secondary batteries for energy redistribution. LIBs are the most popular choice for practical portable electronics (such as mobile phones, laptops, and electronic vehicles) because they provide high energy density and long-term stability. Organic electrolytes used in lithium-ion batteries are both useful and dangerous due to their flammability and toxicity, thus posing safety risks. Lithium resources are limited, the cost is high, and the energy storage conditions of lithium batteries are harsh, which hinders their application in large-scale energy storage systems. As the global energy structure transitions to clean energy, aqueous zinc-ion batteries (ZIBs) are regarded as an important supplement or even substitute for lithium-ion batteries (LIBs) due to their high safety, low cost, and environmental friendliness. Zinc metal anodes have the advantages of abundant zinc resources (75 ppm in the earth's crust), high theoretical capacity (819 mA hg -1 ), low redox potential (-0.763 V vs. SHE) and high ionic conductivity of aqueous electrolyte (1 S cm -1 ) and other advantages, becoming the core component of ZIB. However, the zinc anode still faces bottlenecks in practical applications, which seriously restricts its large-scale commercialization process. Specifically, taking the zinc metal negative electrode as the research entry point, it faces a series of thorny problems such as dendrite growth, poor deposition uniformity, hydrogen evolution reaction and corrosion. In view of the fact that the proper solution of these problems plays a vital role in building a stable aqueous zinc-ion battery system, scientific researchers have invested a lot of energy in developing a series of improvement strategies aimed at optimizing the electrochemical performance of batteries, covering zinc surface structural modification strategies, alloying modification paths and interface coating preparation methods. Looking back on the development history of coating materials, traditional applications include polymers, precious metals and rare earth materials. However, polymers have disadvantages such as complex preparation process and high recycling costs, which to a large extent limit their large-scale promotion and application; precious metals and rare earth materials are difficult to meet the needs of continued expansion of the industry due to their inherent scarcity. In the existing technology, some studies have used the deposition method to prepare an artificial interface layer of silver nanoparticles. Although silver nanoparticles have excellent electrostatic shielding effects, they have many problems as an artificial interface layer, such as poor adhesion, unstable chemical properties, and easy reaction with the electrolyte. Summary of the Invention

[0003] In order to overcome the shortcomings of the existing technology and address the problems of dendrites on the surface of the zinc negative electrode, electrolyte corrosion, and uneven deposition of zinc ions, the present invention provides a preparation method and application of a negative electrode coating material for an aqueous zinc ion battery. The coating material is a simple coating material prepared by loading active substance nano-Ag on carbon nitride and a simple deposition method. The interface coating is deposited on zinc foil to modify the interface properties of the zinc negative electrode. When used as an aqueous zinc ion battery, the battery capacity and cycle stability are significantly improved.

[0004] The present invention provides a preparation method and application of a negative electrode coating material for an aqueous zinc ion battery. The material is a silver-loaded carbon nitride composite material, and the composite material is used as an artificial interface layer for the negative electrode of an aqueous zinc ion battery. A silver-loaded carbon nitride composite nanomaterial is used as the zinc negative electrode interface coating. Silver nanoparticles can effectively improve the electrostatic shielding of the zinc negative electrode surface, making zinc ions more easily deposited and inhibiting the growth of zinc dendrites. The material also has excellent mechanical strength and chemical stability, effectively inhibiting corrosion of the negative electrode by the electrolyte. The protective layer preparation process is simple, the prepared coating has strong adhesion, and a stable interface layer is easily formed. The half-cell cycle efficiency and stability are significantly improved, and the full battery can stably cycle 1323 times, thereby extending the service life of the aqueous zinc ion battery.

[0005] The above-mentioned object of the present invention is achieved through the following technical solutions:

[0006] A method for preparing a negative electrode coating material for an aqueous zinc ion battery comprises the following steps:

[0007] S1. Grind melamine to obtain a powder;

[0008] S2. The powder was placed in a tube furnace to obtain a yellow solid powder CN;

[0009] S3. The yellow solid powder CN was dissolved in aqueous ammonia to obtain a mixed solution;

[0010] S4. Add silver chloride solid to the mixed solution, sonicate, further add ascorbic acid solution, sonicate, and stir for 5-7 hours to obtain a gray solution. Filter to obtain a solid powder named Ag / CN.

[0011] Furthermore, in step S2, the specific sintering conditions for the tube furnace heat treatment are: a heating rate of 2.0-2.5°C / min, a calcination temperature of 540-560°C, a calcination time of 50-70 minutes, and an argon atmosphere. Preferably, the heating rate is 2.3°C / min, the calcination temperature is 550°C, and the calcination time is 60 minutes.

[0012] Furthermore, in steps S3 and S4, the mass ratio of CN to silver chloride solid added is 10:1-5:2, and ultrasonication is performed for 10-15 minutes to obtain a mixed solution.

[0013] Furthermore, in step S4, the volume ratio of the added ascorbic acid solution to the reaction system is 6:1-2:1.

[0014] Furthermore, in step S4, the ascorbic acid with a mass fraction of 9% to 11% is a newly prepared solution. Preferably, the ascorbic acid with a mass fraction of 10% is a newly prepared solution.

[0015] Furthermore, in step S4, the product is filtered and washed 3-4 times with distilled water and ethanol respectively to obtain a gray solid powder.

[0016] Furthermore, in step S4, the first ultrasonication is performed for 10-15 minutes, and the second ultrasonication is performed for 10-15 minutes. Preferably, the first ultrasonication is performed for 10 minutes, and the second ultrasonication is performed for 10 minutes.

[0017] Furthermore, in step S4, stirring is performed for 6 hours.

[0018] The present invention also claims the use of the aqueous zinc ion battery negative electrode coating material prepared by the above-mentioned preparation method in preparing the negative electrode of the aqueous zinc ion battery. The prepared Ag / CN is coated on the surface of zinc foil to form an Ag / CN-Zn electrode sheet. The Ag / CN serves as an artificial interface layer for the negative electrode of the aqueous zinc ion battery.

[0019] The specific application is: Ag / CN and polyvinylidene fluoride (PVDF) are mixed evenly in a mass ratio of 5:1, N-methylpyrrolidone (NMP) is added dropwise and stirred until it becomes viscous, and then dripped onto the surface of zinc foil to form an Ag / CN-Zn electrode sheet.

[0020] The artificial interface layer for the zinc anode is a composite material coated on the surface of a metallic zinc foil. Silver nanoparticles are loaded onto carbon nitride to create silver-loaded carbon nitride (Ag / CN). This layer is chemically stable and mechanically strong. It effectively improves electrostatic shielding on the zinc anode surface, allowing for uniform zinc ion deposition. It also resists reaction with the electrolyte, isolating the electrolyte from direct contact with the zinc anode surface, reducing electrolyte corrosion. Compared to previous studies using synthetic silver nanowires or graphene oxide as a carrier, which suffer from complex preparation processes and expensive raw materials, this protective layer utilizes readily available raw materials and a simple preparation process. The resulting symmetrical battery significantly reduces impedance and significantly improves half-cell cycle efficiency stability, extending the lifespan of aqueous zinc-ion batteries.

[0021] The beneficial effects of the present invention compared with the prior art are:

[0022] (1) The present invention provides a method for preparing a negative electrode coating material for an aqueous zinc ion battery. The method comprises depositing a silver-loaded carbon nitride composite nanomaterial on the surface of a metal zinc foil to form an interface coating, providing abundant zinc-philic active sites such as Ag and N, thereby inducing uniform deposition of zinc ions, inhibiting the growth of zinc dendrites, and improving the charge-discharge capacity retention rate and cycle life of the aqueous zinc ion battery. The negative electrode material prepared from the silver-loaded carbon nitride composite nanomaterial can stably cycle 1323 times in an aqueous zinc ion half-cell test and can be applied to an aqueous zinc ion full battery.

[0023] (2) The present invention provides a method for preparing a negative electrode coating material for an aqueous zinc ion battery. Different from the existing methods (graphene and carbon cloth have been used as carriers in previous studies, but these carriers are difficult to prepare, expensive, and have insignificant effects), the present invention adopts a silver-loaded carbon nitride composite nanomaterial as the zinc negative electrode interface coating. Silver nanoparticles can effectively improve the electrostatic shielding of the zinc negative electrode surface, making zinc ions easier to deposit. At the same time, carbon nitride as a carrier of silver nanoparticles has excellent mechanical strength and stable chemical properties, which can prevent silver nanoparticles from chemically reacting with the electrolyte and dissolving in the electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the SEM spectrum of Ag / CN-Zn prepared in Example 1.

[0025] Figure 2 This is the XRD spectrum of Ag / CN-Zn prepared in Example 1.

[0026] Figure 3 This is a comparison chart of half-cell efficiency versus cycle number for Ag / CN-Zn prepared in Example 1, Bare Zn prepared in Comparative Example 1, and CN-Zn prepared in Comparative Example 2.

[0027] Figure 4 This is a half-cell capacity-voltage comparison diagram of Ag / CN-Zn prepared in Example 1, Bare Zn prepared in Comparative Example 1, and CN-Zn prepared in Comparative Example 2.

[0028] Figure 5 This is a time-voltage comparison chart of the symmetrical battery of Ag / CN-Zn prepared in Example 1 and Bare Zn prepared in Comparative Example 1.

[0029] Figure 6 This is a comparison chart of half-cell efficiency versus cycle number for Ag / CN-Zn prepared in Example 1, Bare Zn prepared in Comparative Example 1, and Ag / CN-Zn-1 prepared in Comparative Example 3.

[0030] Figure 7This is a half-cell capacity-voltage comparison diagram of Ag / CN-Zn prepared in Example 1, Bare Zn prepared in Comparative Example 1, and Ag / CN-Zn-1 prepared in Comparative Example 3. DETAILED DESCRIPTION

[0031] The present invention is described in detail below by specific examples, but the scope of protection of the present invention is not limited. Unless otherwise specified, the experimental methods adopted in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can be obtained from commercial channels.

[0032] The present invention first prepares carbon nitride through a simple thermal synthesis method, uses the carbon nitride as a carrier to load nanosilver particles to prepare a silver-loaded carbon nitride composite nanomaterial, and uses the material as an interface coating for the negative electrode of an aqueous zinc ion battery to modify the negative electrode. The silver-loaded carbon nitride composite material prepared by the present invention is used as the interface coating for the negative electrode of an aqueous zinc ion battery, providing abundant zinc-philic active sites such as Ag and N, which induce uniform deposition of zinc ions. At the same time, the silver nanoparticles can improve the electrostatic shielding effect on the surface of the zinc negative electrode, inhibiting hydrogen evolution reactions and side reactions. The material also has excellent mechanical properties and chemical stability, effectively reducing electrolyte corrosion on the zinc negative electrode, and improving the cycle stability of the assembled battery.

[0033] Example 1

[0034] A method for preparing a negative electrode coating material for an aqueous zinc ion battery.

[0035] (1) Grinding melamine to obtain powder A;

[0036] (2) Powder A was placed in a porcelain boat and heated in a tube furnace at a heating rate of 2.3°C / min to 550°C for 4 hours, calcined for 60 minutes, and cooled to room temperature to obtain a yellow solid powder named CN;

[0037] (3) Dissolve 100 mg of CN in 15 ml of ammonia water and sonicate for 10 minutes. Then add 20 mg of AgCl and sonicate for 10 minutes to obtain solution A.

[0038] (4) Add 5 ml of 10% ascorbic acid to solution A and sonicate for 10 minutes. Continue stirring for 6 hours to obtain a gray solution B.

[0039] (5) The gray solution B was filtered and washed three times with distilled water and ethanol respectively to obtain a gray solid product named Ag / CN;

[0040] (6) Ag / CN and polyvinylidene fluoride (PVDF) were mixed uniformly in a mass ratio of 5:1, and 33-36 drops of N-methylpyrrolidone (NMP) were added and stirred until a viscous solution was obtained.

[0041] (7) 10 μL of the mixed viscous solution was pipetted onto zinc foil and then pressed into a 12 mm circular electrode sheet as the negative electrode material using a punch. The negative electrode material was named Ag / CN-Zn.

[0042] Comparative Example 1

[0043] The metal zinc foil is not treated in any way and is named Bare Zn.

[0044] Comparative Example 2

[0045] (1) Grinding melamine to obtain powder A;

[0046] (2) Powder A was placed in a porcelain boat and heated in a tube furnace at a heating rate of 2.3°C / min to 550°C for 4 hours, calcined for 60 minutes, and cooled to room temperature to obtain a yellow solid powder named CN;

[0047] (3) Yellow solid powder CN and polyvinylidene fluoride (PVDF) were mixed in a ratio of 5:1 (mass ratio), and 33-36 drops of N-methylpyrrolidone (NMP) were added and stirred to prepare a mixed viscous solution.

[0048] (4) 10 μL of the mixed viscous solution was pipetted onto the zinc foil and pressed into a 12 mm circular electrode sheet as the negative electrode material using a punch. The negative electrode material was named CN-Zn.

[0049] Comparative Example 3

[0050] (1) Grinding melamine to obtain powder A;

[0051] (2) Powder A was placed in a porcelain boat and heated in a tube furnace at a heating rate of 2.3°C / min to 550°C for 4 hours, calcined for 60 minutes, and cooled to room temperature to obtain a yellow solid powder named CN;

[0052] (3) Dissolve 100 mg of CN in 15 ml of ammonia water and sonicate for 10 minutes. Then add 20 mg of AgCl and sonicate for 10 minutes to obtain solution A.

[0053] (4) The gray solution A was filtered and washed three times with distilled water and ethanol respectively to obtain a gray solid product named Ag / CN;

[0054] (5) Ag / CN and polyvinylidene fluoride (PVDF) were mixed uniformly in a mass ratio of 5:1, and 33-36 drops of N-methylpyrrolidone (NMP) were added and stirred until a viscous solution was obtained.

[0055] (7) 10 μL of the mixed viscous solution was pipetted onto zinc foil and then pressed into a 12 mm circular electrode sheet as the negative electrode material using a punch. The negative electrode material was named Ag / CN-Zn-1.

[0056] Application Example 1

[0057] The negative electrode material Ag / CN-Zn prepared in Example 1 was assembled into an aqueous zinc ion half-cell, wherein the positive electrode was copper foil, the negative electrode was the Ag / CN-Zn electrode material prepared in Example 1, and the electrolyte was 2 mol L -1 Various electrochemical tests were conducted in zinc sulfate solution. The test conditions were: a current density of 5 mA cm -2 , capacity cutoff 1mAh cm -2 Half-cell test was performed under the following conditions.

[0058] The negative electrode material Ag / CN-Zn prepared in Example 1 was assembled into an aqueous zinc ion symmetrical battery, wherein the positive electrode was the Ag / CN-Zn material prepared in Example 1, the negative electrode was the Ag / CN-Zn material prepared in Example 1, and the electrolyte was 2 mol L -1 Various electrochemical tests were conducted in zinc sulfate solution. The test conditions were: a current density of 3 mA cm -2 , capacity cutoff 0.5 mAh cm -2 Symmetrical battery test was performed for the conditions.

[0059] Test results: attached Figure 1 The scanning electron microscope image of the Ag / CN-Zn electrode material prepared in Example 1 shows that it has a rich pore structure and a high specific surface area, which increases the Zn 2+ Deposition sites and transport channels. Figure 2 The XRD spectrum of Ag / CN-Zn prepared in Example 1 is shown in FIG. Figure 3 The half-cell assembled with the Ag / CN-Zn negative electrode material prepared in Example 1 was charged at a current density of 5 mA cm -2 , capacity cutoff 1mAh cm -2 The test cycle was stable for 1323 times, and the CE was stable at about 97%, showing excellent galvanizing / stripping recoverability. Figure 4 The half-cell nucleation overpotential of the Ag / CN-Zn electrode material assembled in Example 1 is 21.2 mV, which is much lower than the 79.5 mV nucleation overpotential of the half-cell assembled in the Bare Zn electrode material prepared in Comparative Example 2. The stability of the coating material for aqueous zinc ion batteries is significantly better than that of the prior art. Figure 5 It can be seen that the Ag / CN-Zn symmetrical battery prepared in Example 1 can be stably cycled for 400 hours, while the Bare Zn symmetrical battery prepared in Comparative Example 2 can only be stably cycled for 45 hours.

[0060] Comparative Application Example 1

[0061] The Bare Zn half-cell prepared in Comparative Example 1 was tested, wherein the positive electrode material was copper foil, the negative electrode material was the Bare Zn electrode material prepared in Comparative Example 1, and the electrolyte was 2 mol L -1 Various electrochemical tests were conducted in zinc sulfate solution. The test conditions were: a current density of 5 mA cm -2 , capacity cutoff 1mAh cm -2 .

[0062] The negative electrode material Bare Zn prepared in Comparative Example 1 was assembled into an aqueous zinc ion symmetrical battery, wherein the positive electrode was the Bare Zn electrode material prepared in Comparative Example 1, the negative electrode was the Bare Zn electrode material prepared in Comparative Example 1, and the electrolyte was 2 mol L -1 Various electrochemical tests were conducted in zinc sulfate solution. The test conditions were: a current density of 3 mA cm -2 , capacity cutoff 0.5 mAh cm -2 Symmetrical battery test was performed for the conditions.

[0063] Test results: attached Figure 3 It can be seen that the half-cell assembled with Bare Zn prepared in Comparative Example 1 can only be stably cycled for 112 cycles and a short circuit occurs at the 113th cycle. Figure 4 The nucleation overpotential of the half-cell assembled with Bare Zn prepared in Comparative Example 1 is 79.5 mV. Figure 5 The symmetrical battery assembled with bare Zn prepared in Comparative Example 1 can only be stably cycled for 45 hours.

[0064] Application Comparative Example 2

[0065] The negative electrode material CN-Zn prepared in Comparative Example 2 was assembled into an aqueous zinc ion half-cell, wherein the positive electrode was copper foil, the negative electrode was the CN-Zn electrode material prepared in Comparative Example 2, and the electrolyte was 2 mol L -1 Various electrochemical tests were conducted in zinc sulfate solution. The test conditions were: a current density of 5 mA cm -2 , capacity cutoff 1mAh cm -2 Half-cell test was performed under the following conditions.

[0066] Test results: attached Figure 3 The half-cell assembled with the CN-Zn negative electrode material prepared in Comparative Example 2 was charged at a current density of 5 mA cm -2 , capacity cutoff 1mAh cm -2 Under the test, it can only stably cycle 350 times, and the CE is stable at about 93%. Figure 4The half-cell nucleation overpotential of the CN-Zn electrode material assembly prepared in Comparative Example 2 is 65.2 mV, which is much lower than the half-cell nucleation overpotential of the Ag / CN-Zn electrode material assembly prepared in Example 1.

[0067] Application Comparative Example 3

[0068] The negative electrode material Ag / CN-Zn-1 prepared in Comparative Example 3 was assembled into an aqueous zinc ion half-cell, wherein the positive electrode was copper foil, the negative electrode was the Ag / CN-Zn-1 electrode material prepared in Comparative Example 3, and the electrolyte was 2 mol L -1 Various electrochemical tests were conducted in zinc sulfate solution. The test conditions were: a current density of 5 mA cm -2 , capacity cutoff 1mAh cm -2 Half-cell test was performed under the following conditions.

[0069] Test results: attached Figure 6 The half-cell assembled with the Ag / CN-Zn-1 negative electrode material prepared in Comparative Example 3 was charged at a current density of 5 mA cm -2 , capacity cutoff 1mAh cm -2 Under the test, it can only stably cycle 290 times, and the CE is stable at about 89%. Figure 7 The half-cell nucleation overpotential of the Ag / CN-Zn-1 electrode material assembly prepared in Comparative Example 3 is 51.4 mV, which is much lower than the half-cell nucleation overpotential of the Ag / CN-Zn electrode material assembly prepared in Example 1.

[0070] The above-described embodiments are only preferred embodiments of the present invention, and are not intended to be all feasible embodiments of the present invention. Any obvious modifications made by a person skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a negative electrode coating material for an aqueous zinc ion battery, characterized in that: The following steps are involved: S1. Grind melamine to obtain a powder; S2. The powder was placed in a tube furnace to obtain a yellow solid powder CN; S3. The yellow solid powder CN was dissolved in aqueous ammonia to obtain a mixed solution; S4. Add silver chloride solid to the mixed solution, sonicate, further add ascorbic acid solution, sonicate, and stir for 5-7 hours to obtain a gray solution. Filter to obtain a solid powder named Ag / CN.

2. The method for preparing a negative electrode coating material for an aqueous zinc ion battery according to claim 1, wherein: In step S2, the specific sintering conditions of the tube furnace heat treatment are: a heating rate of 2.0-2.5°C / min, a calcination temperature of 540-560°C, a calcination time of 50-70 minutes, and an argon atmosphere.

3. The method for preparing a negative electrode coating material for an aqueous zinc ion battery according to claim 1, wherein: In steps S3 and S4, the mass ratio of CN to silver chloride solid added is 10:1-5:2, and ultrasonication is performed for 10-15 minutes to obtain a mixed solution.

4. The method for preparing a negative electrode coating material for an aqueous zinc ion battery according to claim 1, wherein: In step S4, the volume ratio of the added ascorbic acid solution to the reaction system is 6:1-2:

1.

5. The method for preparing a negative electrode coating material for an aqueous zinc ion battery according to claim 1, wherein: In step S4, the product is filtered and washed with distilled water and ethanol for 3-4 times respectively to obtain a gray solid powder.

6. The method for preparing a negative electrode coating material for an aqueous zinc ion battery according to claim 1, wherein: In step S4, the ascorbic acid solution with a mass fraction of 9% to 11% is a newly prepared solution.

7. The method for preparing a negative electrode coating material for an aqueous zinc ion battery according to claim 1, wherein: In step S4, the first ultrasonication is performed for 10-15 minutes, and the second ultrasonication is performed for 10-15 minutes.

8. Use of the aqueous zinc ion battery negative electrode coating material prepared by the preparation method according to any one of claims 1 to 6 in preparing the negative electrode of an aqueous zinc ion battery.

9. The use according to claim 7, characterized in that: The prepared Ag / CN was coated on the surface of zinc foil to make an Ag / CN-Zn electrode sheet, where Ag / CN served as the artificial interface layer of the negative electrode of the aqueous zinc ion battery.

10. The use according to claim 7, characterized in that: Ag / CN and polyvinylidene fluoride were mixed evenly in a mass ratio of 5:1, N-methylpyrrolidone was added dropwise and stirred until viscous, and then dropped onto the surface of zinc foil to form an Ag / CN-Zn electrode sheet.

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