A protective layer material for zinc anode of aqueous zinc-ion battery and a preparation method and application thereof

Abstract

The application discloses a kind of water-based zinc ion battery zinc negative electrode protective layer material and its preparation method and application.The method is: carbon material is dispersed in acidic liquid, stirring at room temperature, so that it is fully mixed, and a uniform suspension is obtained;Manganese salt is added to the mixed solution, stirring at room temperature, followed by constant temperature water bath;The product obtained by reaction is washed, centrifuged, dried, calcined to obtain expanded graphite;The expanded graphite is uniformly dispersed in the solvent, and a dispersion is obtained by stirring;Titanium-containing organic compound is added to the dispersion and stirred;Deionized water is added to the dispersion and refluxed;Centrifugation, washing, drying, calcination to obtain a protective layer.The composite material is first prepared by expanding graphite, and then titanium dioxide quantum dots are anchored thereon.The material has excellent zinc ion rate, lower interfacial resistance, good cycle stability and rate performance compared to prior art, and improves the problem of interface dendrite growth.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of aqueous zinc ion batteries, in particular to a zinc ion battery negative electrode protective layer material, a preparation method thereof and application of the zinc ion battery negative electrode material in an aqueous zinc ion battery. BACKGROUND

[0002] In recent years, industrial production and infrastructure construction have experienced rapid development, prompting people to pay more attention to the safe operation and maintenance of these fields. Metal materials play an important role in these production facilities and public life. With the progress of science and technology and the improvement of living standards, people's demand for energy storage technology has also grown. Among many electrochemical energy storage devices, lithium ion batteries are widely used due to their high energy density and long service life, but they are not suitable for large-scale energy storage systems due to high cost and safety risks. Organic electrolyte has the advantages of low thermal stability and high conductivity, and has become the most common electrolyte in current lithium ion battery applications. However, due to the flammability and toxicity of organic electrolyte, the development of batteries has been limited. As an environmentally friendly energy storage system, rechargeable aqueous batteries are attracting attention due to their low cost, high safety and good durability, and have shown great application potential in many fields. In particular, the development of aqueous zinc ion batteries (ZIBs) has been the most rapid, mainly due to the following points: (1) zinc metal has a relatively high capacity density (5855 mAh·cm -3 ) and a redox potential equivalent to the standard hydrogen electrode (SHE); (2) abundant zinc resources provide a guarantee for the sustainable development of ZIBs, which not only has low cost, but also has the advantage of high safety; (3) the conventional electrolyte uses a neutral or weakly acidic aqueous solution, which has an electrical conductivity (about 1 S·cm -1 ) two orders of magnitude higher than that of non-aqueous electrolyte (about 1-10 mS·cm -1 ). However, the corrosion problem of zinc metal negative electrode is still a key factor hindering its development, which seriously weakens the stability and service life of zinc ion batteries in practical applications. Therefore, it has great application value to study how to prevent the corrosion of zinc metal negative electrode.

[0003] Patent CN117577766A discloses a preparation method of a zinc negative electrode protective coating for aqueous zinc ion batteries, which uses a metal zinc negative electrode as a substrate and uniformly mixes sulfonated polyaniline and acrylic resin in ethanol to form a protective coating with both conductive and corrosion-resistant functions. The metal zinc negative electrode protected by the coating can operate at a current density of 5 mA cm -2 and a surface capacity of 5 mAh cm -2The symmetrical battery assembled thereby can also be stably cycled for 250 hours, effectively prolonging the cycle life of the symmetrical battery. The patent CN117457843A discloses a polyacrylamide polymer coating layer modified on the surface of a zinc negative electrode of a water-based zinc ion battery by a spin coating method. The synthesized coating layer has good adhesion. The prepared polymer coating layer can effectively isolate the contact between the electrode and the electrolyte, and inhibit the occurrence of side reactions. In addition, the amide group exhibits strong zinc ion adsorption capacity, which can effectively regulate the uniform deposition of zinc ions. Therefore, the assembled battery realizes good cycle stability

[0004] In order to reflect the improvement of the zinc-loving material on the cycle life of the water-based zinc ion battery, in view of this, the present application designs a low-cost and high-safety protective layer, which effectively alleviates the problems of dendrite growth, interface corrosion and the like. SUMMARY

[0005] In order to overcome the problems of rampant dendrite growth of the existing zinc negative electrode and short cycle life of the water-based zinc ion battery, the present application provides a porous water-based zinc ion protective layer which is simple in process, low in cost, high in safety, green and environmentally friendly, and has the advantages of large-scale production.

[0006] Another object of the present application is to provide an application of a porous composite material in a negative electrode of a water-based zinc ion battery, which improves the corrosion resistance, cycle life, coulombic efficiency and the like of the symmetrical battery, and improves the capacity and rate performance of the full battery.

[0007] The object of the present application is achieved by the following technical solutions:

[0008] The present application provides a preparation method of a zinc negative electrode protective layer material of a water-based zinc ion battery, comprising the following steps:

[0009] (1) dispersing the carbon material in an acidic liquid, stirring at room temperature to make them fully mixed, and obtaining a uniform suspension;

[0010] (2) adding manganese salt to the mixed solution obtained in step (1), stirring at room temperature, and then constant temperature water bath;

[0011] (3) washing, centrifuging, drying and calcining the product obtained by reaction to obtain expanded graphite;

[0012] (4) uniformly dispersing the expanded graphite obtained in step (3) in a solvent and stirring to obtain a dispersion;

[0013] (5) adding a titanium-containing organic compound to the dispersion obtained in step (4) and stirring;

[0014] (6) adding deionized water to the dispersion obtained in step (5) and refluxing;

[0015] (7) centrifuging, washing, drying, calcining the product obtained in step (6) to obtain a protective layer.

[0016] Further, in step (1), the carbon material is graphite; and the acidic liquid is 50-80% sulfuric acid.

[0017] Further, in step (2), the manganese salt is potassium permanganate; the stirring time is 0.5-2 hours; the constant temperature water bath time is 0.5-2 hours; and the water bath temperature is 30-100℃.

[0018] Further, in step (3), the washing is to neutralize the material; the drying time is 10-14 hours, and the drying temperature is 60-100℃.

[0019] The calcining temperature is 700-1100℃, and the calcining time is 10-60 minutes.

[0020] Further, in step (4), the expanded graphite is added in an amount of 0.2-2 g / mL; the solvent is ethanol; and the stirring time is 0.1-1 hour.

[0021] Further, in step (5), the titanium-containing organic compound is tetrabutyl titanate; the volume ratio of the titanium-containing organic compound to the ethanol dispersion is 0.5:100-1:100; and the stirring time is 0.1-1 hour.

[0022] Further, in step (6), the volume ratio of the deionized water to the ethanol dispersion is 0.1:50-2:50; the reflux temperature is 60-150℃; and the reflux time is 4-10 hours.

[0023] Further, in step (7), the product is centrifuged 1-5 times; the drying time is 8-16 hours; the drying temperature is 60-100℃; the calcining temperature is 300-500℃; and the calcining time is 2-6 hours.

[0024] The application provides a protective layer of titanium dioxide quantum dot loaded expanded graphite prepared by the preparation method.

[0025] The application provides application of the material of titanium dioxide quantum dot loaded expanded graphite in a zinc negative electrode interface of a water-based zinc ion battery.

[0026] Preferably, the material of titanium dioxide quantum dot loaded expanded graphite is used as a protective layer of a negative electrode of a water-based zinc ion battery, and is dissolved in NMP in a certain proportion with conductive carbon black and a binder, is coated on a zinc foil by pulping, and is used to form a button cell with manganese dioxide as a positive electrode for electrochemical testing.

[0027] Further, the binder is PVDF; preferably, the protective layer powder: conductive carbon black: PVDF is 7:2:1.

[0028] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0029] 1) The present application provides abundant pore structure for zinc ion deposition by the chemical oxidation method, so that the zinc ions can be uniformly deposited on the negative electrode surface, effectively reducing the growth of dendrites.

[0030] 2) The present application uses titanium dioxide quantum dots as zinc-loving materials, effectively reduces the deposition potential of zinc ions, so that the zinc ions can be deposited faster, reduces the hydrogen evolution overpotential of the zinc negative electrode, reduces the corrosion tendency of the zinc negative electrode, reduces the generation of side reactions, and improves the corrosion resistance of the zinc negative electrode.

[0031] 3) The zinc negative electrode protection strategy provided by the present application significantly improves the cycle life of the symmetrical battery under large, medium and small current densities, and the capacity and rate performance of the full battery are also improved accordingly.

[0032] 4) The method for loading titanium dioxide quantum dots on graphite material is simple, efficient, low-cost, and the reagents used are safe and environmentally friendly, which has practical commercialization and large-scale production prospects.

[0033] 5) The raw materials used in the present application are widely available, and the preparation methods are various, which provides a reference for people to prepare high-performance aqueous zinc ion battery negative electrode protection layer. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The scanning electron microscope (SEM) characterization graph of the expanded graphite (TiO2 QDs@EG) with titanium dioxide quantum dots loaded obtained in Example 1.

[0035] Figure 2 The transmission electron microscope (TEM) characterization graph of the negative electrode protection layer (TiO2 QDs@EG) with titanium dioxide quantum dots loaded expanded graphite obtained in Example 1.

[0036] Figure 3 The high-resolution transmission electron microscope (HR-TEM) graph of the negative electrode protection layer (TiO2 QDs@EG) with titanium dioxide quantum dots loaded expanded graphite obtained in Example 1.

[0037] Figure 4 The XPS spectrum of the negative electrode protection layer (TiO2 QDs@EG) with titanium dioxide quantum dots loaded expanded graphite obtained in Example 1.

[0038] Figure 5 Linear scan voltammetry plots of the negative electrode protective layer with titanium dioxide quantum dots supported on expanded graphite (TiO2QDs@EG) obtained in Example 1, the negative electrode protective layer with expanded graphite obtained in Comparative Example 1, and the bare zinc electrode with the protective layer assembled.

[0039] Figure 6 The chronoamperograms are for the negative electrode protective layer with titanium dioxide quantum dots loaded with expanded graphite (TiO2QDs@EG) obtained in Example 1, the negative electrode protective layer with expanded graphite obtained in Comparative Example 1, and the bare zinc electrode with the protective layer assembled.

[0040] Figure 7 The negative electrode protective layer (TiO2 QDs@EG) with titanium dioxide quantum dots supported on expanded graphite obtained in Example 1 was tested at a current of 5 mA cm⁻¹. -2 The capacity is 2.5mAh cm -2 Cyclic performance under certain conditions.

[0041] Figure 8 The image shows the scanning electron microscope (SEM) characterization of the symmetric battery with a titanium dioxide quantum dot-supported expanded graphite negative electrode protective layer (TiO2 QDs@EG) obtained in Example 1 after 100 cycles.

[0042] Figure 9 This is a long-cycle performance test diagram of the full cell composed of a negative electrode protective layer (TiO2 QDs@EG) with titanium dioxide quantum dots supported on expanded graphite and a manganese oxide electrode obtained in Example 1.

[0043] Figure 10 The self-discharge behavior of the full cell in the electrolyte, consisting of a negative electrode protective layer (TiO2QDs@EG) with titanium dioxide quantum dots supported on expanded graphite and a manganese oxide electrode, obtained in Example 1. Detailed Implementation

[0044] The present invention will be further described below with reference to embodiments, comparative examples, and accompanying drawings, but the implementation of the present invention is not limited thereto. It should be noted that any processes not specifically described in detail below are those that can be implemented or understood by those skilled in the art by referring to existing technology. Reagents or instruments whose manufacturers are not specified are considered to be conventional products that can be purchased commercially.

[0045] Example 1

[0046] This embodiment provides a method for preparing a negative electrode protective layer of titanium dioxide quantum dots supported on expanded graphite (TiO2 QDs@EG), the preparation method comprising the following steps:

[0047] (1) 1 g of graphite was added to a beaker, 8 mL of 75% sulfuric acid was added to the beaker, the above dispersion was covered with a layer of plastic wrap and stirred at room temperature for 30 min, and the solution was named solution (1).

[0048] (2) 0.5 g of potassium permanganate was slowly added to solution (1), then placed in a constant temperature water bath at 45°C, reacted for one hour, then the obtained material was watered to neutral and placed in an oven at 80°C for drying for 12 h.

[0049] (3) The dried product obtained in step (2) was placed in a porcelain boat and placed in a muffle furnace at 900°C for 30 min to obtain the final product, expanded graphite (EG).

[0050] (4) 0.5 g of the synthesized expanded graphite (EG) was taken and placed in 100 mL of ethanol for ultrasonic treatment for 30 min, the obtained suspension was added to 1.25 mL of tetrabutyl titanate and stirred for 30 min, then 1.25 mL of deionized water was added, and the obtained suspension was refluxed at 100°C for 6 h.

[0051] (5) The obtained product was washed with ethanol and deionized water alternately for 3 times, placed in an oven at 80°C for drying for 12 h, and then calcined at 400°C for 4 h under Ar atmosphere to obtain a titanium dioxide quantum dot loaded expanded graphite material.

[0052] 0.3 g of the prepared titanium dioxide quantum dot loaded expanded graphite material, 0.0857 g of conductive carbon black, and 0.0428 g of polyvinylidene fluoride were weighed, ground in a mortar, and then transferred to a finger bottle, 2.4 mL of nitrogen methyl pyrrolidone was added, and magnetic stirring was performed for 12 h, then the material was uniformly coated on zinc foil using a coater. It was placed in an oven at 80°C for drying for 12 h. Finally, the obtained material was cut into a 1.2 cm circular electrode, and manganese oxide was used as the positive electrode material to form a CR2032 type button cell.

[0053] Figure 1 The scanning electron microscope (SEM) characterization diagram of the titanium dioxide quantum dot loaded expanded graphite material (TiO2 QDs@EG) obtained in Example 1. From the diagram, it can be observed that the EG is piled up like a coral reef, showing a circular feature. Figure 1

[0054] Figure 2 The transmission electron microscope (TEM) characterization diagram of the titanium dioxide quantum dot loaded expanded graphite material (TiO2 QDs@EG) obtained in Example 1. From the diagram, it can be seen that the titanium dioxide quantum dots are anchored on the surface of the expanded graphite, and the average size is about 10 nm. Figure 2

[0055] Figure 3 ​​High resolution transmission electron microscopy (HR-TEM) image of the material with titanium dioxide quantum dots loaded expanded graphite (TiO2 QDs@EG) obtained in Example 1. From Figure 3 It can be seen that the interplanar spacing of titanium dioxide quantum dots is 0.352 nm, which is very consistent with the (101) lattice plane of anatase TiO2. At the same time, the interplanar distance of EG is measured to be 0.337 nm and 0.203 nm, respectively, corresponding to the (002) plane and (101) plane of graphite.

[0056] Figure 4 XPS spectrum of the material with titanium dioxide quantum dots loaded expanded graphite (TiO2 QDs@EG) obtained in Example 1. From Figure 4 It can be seen that the full spectrum of EG@TiO2 QDs, which is mainly composed of several sharp peaks, corresponds to carbon, oxygen, titanium elements, respectively.

[0057] Figure 5 Linear sweep voltammograms of the negative electrode protective layer with titanium dioxide quantum dots loaded expanded graphite (TiO2 QDs@EG) obtained in Example 1, the negative electrode protective layer with expanded graphite obtained in Comparative Example 1, and the bare zinc electrode with protective layer assembled. From Figure 5 It can be seen that the hydrogen evolution overpotential of the negative electrode with protective layer is less than that of the bare zinc electrode, which shows that the protective layer effectively alleviates the hydrogen evolution side reaction.

[0058] Figure 5 Chronoamperograms of the negative electrode protective layer with titanium dioxide quantum dots loaded expanded graphite (TiO2 QDs@EG) obtained in Example 1, the negative electrode protective layer with expanded graphite obtained in Comparative Example 1, and the bare zinc electrode with protective layer assembled. From Figure 6 It can be seen that in the bare zinc electrode and EG@Zn, the current density continues to rise within 300 s, showing a long and rampant two-dimensional diffusion process, in which Zn2+ tends to diffuse horizontally along the surface and is easy to deposit in the tip to form dendrites. In sharp contrast, after the limited two-dimensional diffusion, the long-term 3D diffusion process occurring in ET@Zn has a stable and low current density, which can promote the uniform and flat deposition of zinc and inhibit the growth of zinc dendrites. This is in sharp contrast to the case where Zn2+ diffuses horizontally along the surface and is easy to deposit in the tip to form dendrites.

[0059] Figure 7 Cycling performance of the negative electrode protective layer with titanium dioxide quantum dots loaded expanded graphite (TiO2 QDs@EG) obtained in Example 1 under the condition of current of 5 mA cm -2 , capacity of 2.5 mAh cm -2 . From Figure 7It can be seen that the cycle life of the symmetrical battery assembled with the negative electrode protection layer of titanium dioxide quantum dot loaded expanded graphite reaches 3000h.

[0060] Figure 8 The scanning electron microscope (SEM) characterization diagram of the symmetrical battery with the negative electrode protection layer of titanium dioxide quantum dot loaded expanded graphite (TiO2 QDs@EG) obtained in Example 1 after 100 cycles. From Figure 8 It can be seen that the symmetrical battery assembled with the negative electrode protection layer of titanium dioxide quantum dot loaded expanded graphite has reduced dendrite growth on the surface after 100 cycles, and the dendrites show horizontal growth.

[0061] Figure 9 The long cycle performance test diagram of the full battery composed of the negative electrode protection layer of titanium dioxide quantum dot loaded expanded graphite (TiO2 QDs@EG) obtained in Example 1 and the manganese oxide electrode. From Figure 9 It can be seen that the capacity of the full battery assembled with the negative electrode protection layer of titanium dioxide quantum dot loaded expanded graphite is stable at 100m Ah g -1 , and the coulombic efficiency is also close to 100%.

[0062] Figure 10 The self-discharge behavior of the full battery composed of the negative electrode protection layer of titanium dioxide quantum dot loaded expanded graphite (TiO2 QDs@EG) obtained in Example 1 and the manganese oxide electrode in the electrolyte. From Figure 10 It can be seen that the full battery assembled with the negative electrode protection layer of titanium dioxide quantum dot loaded expanded graphite still maintains a capacity of more than 90% after being fully charged and standing for 48h.

[0063] Example 2

[0064] The present embodiment provides a preparation method of a negative electrode protection layer loaded with expanded graphite (EG), which comprises the following steps:

[0065] (1) 1g of graphite is added to a beaker, and 8mL of 75% sulfuric acid is continuously added to the beaker. The above dispersion is covered with a layer of plastic wrap and stirred at room temperature for 30min. The solution is named solution (1).

[0066] (2) 0.5g of potassium permanganate is slowly added to solution (1), followed by constant temperature water bath at 45°C. After one hour of reaction, the obtained material is watered to neutral and dried in an oven at 80°C for 12h.

[0067] (3) The dried product obtained in step (2) is placed in a porcelain boat and placed in a muffle furnace at 900°C for 30min to obtain the final product expanded graphite (EG).

[0068] The CR2032 type button cell process is the same as that in Example 1.

[0069] Finally, it should be noted that the above examples and related detailed description of the drawings are only for the purpose of illustrating the technical solutions of the present application and not for limiting it, the present application is not limited to the specific embodiments described above, any modification or equivalent replacement within the purpose and scope of the present application without departing from the present application, which should be covered in the scope of protection of the claims of the present application.

Claims

1. A method for preparing a protective layer material for zinc anodes of aqueous zinc-ion batteries, characterized in that, It comprises the following steps: (1) dispersing carbon material in an acidic liquid, stirring at room temperature to make it fully mixed to obtain a uniform suspension; (2) adding manganese salt to the mixed solution obtained in step (1), stirring at room temperature, and then constant temperature water bath; (3) washing, centrifuging, drying and calcining the product obtained by reaction to obtain expanded graphite; (4) uniformly dispersing the expanded graphite obtained in step (3) in a solvent and stirring to obtain a dispersion; (5) adding a titanium-containing organic compound to the dispersion obtained in step (4) and stirring; (6) adding deionized water to the dispersion obtained in step (5) and refluxing; (7) centrifuging, washing, drying and calcining the product obtained in step (6) to obtain a protective layer of expanded graphite loaded with titanium dioxide quantum dots.

2. The method of claim 1, wherein the method is characterized by: In step (1), the carbon material is graphite; the acidic liquid is 50%-80% sulfuric acid.

3. The method of claim 1, wherein the method further comprises the step of: 3-1) adding a dispersant to the mixture of step 2-1) to form a dispersion. In step (2), the manganese salt is potassium permanganate; the stirring time is 0.5-2 hours; the constant temperature water bath time is 0.5-2 hours; the water bath temperature is 30-100℃.

4. The method of claim 1, wherein the method is characterized by: In step (3), the material is washed to neutral during washing; the drying time is 10-14 hours and the drying temperature is 60-100℃; The calcination temperature is 700-1100℃; the calcination time is 10-60 minutes.

5. The method of claim 1, wherein the method is characterized by: In step (4), the mass of expanded graphite added is 0.2-2g / mL; the solvent is ethanol; the stirring time is 0.1-1 hour.

6. The method for preparing a zinc anode protective layer material for an aqueous zinc-ion battery as described in claim 1, characterized in that, In step (5), the titanium-containing organic compound is tetrabutyl titanate; the volume ratio of the titanium-containing organic compound to the ethanol dispersion is 0.5:100-1:100; the stirring time is 0.1-1 hour.

7. The method for preparing a zinc anode protective layer material for an aqueous zinc-ion battery as described in claim 1, characterized in that, In step (6), the volume of deionized water added to the ethanol dispersion is 0.1:50-2:50; the refluxing temperature is 60-150℃; the refluxing time is 4-10 hours.

8. The method of claim 1, wherein the method is characterized by: In step (7), the product is centrifuged 1-5 times; the drying time is 8-16 hours; the drying temperature is 60-100℃; the calcination temperature is 300-500℃; the calcination time is 2-6 hours.

9. The protective layer material for zinc negative electrode of aqueous zinc ion battery prepared by the preparation method of any one of claims 1-8.

10. The application of the protective layer material of claim 9 in the interface of zinc negative electrode of aqueous zinc ion battery.

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