WO2021208619A1 - Electrolyte based on gelatin-manganese ion co-additive and application thereof - Google Patents

Abstract

Provided in the present disclosure are an electrolyte based on a gelatin-manganese ion co-additive and an application thereof. The electrolyte comprises: gelatin, Zn²⁺, Mn²⁺, and water. The electrolyte is low cost, safe and environmentally friendly, has a simple process, and is easy to prepare on a large scale, and can effectively inhibit the growth of zinc dendrites, slowing the corrosion of zinc negative electrodes.

Description

[Corrected according to Rule 26 03.03.2021] 　The electrolyte based on gelatin-manganese ion co-additive and its application

Priority information

This disclosure requests the priority of the Chinese patent application filed with the State Intellectual Property Office of China on April 14, 2020, with a patent application number of 202010288915. 2, and the application title is "Electrolyte based on gelatin-manganese ion co-additive and its application", And its entire content is incorporated into the present disclosure by reference.

Technical field

The present disclosure relates to the field of zinc ion batteries, in particular, the present disclosure relates to electrolytes based on gelatin-manganese ion co-additives and their applications in water-based zinc ion batteries

Background technique

Zinc-ion battery is a new type of secondary water battery developed in recent years. It has the advantages of high energy density, high power density, high efficiency and safety in the discharge process, non-toxic and cheap battery materials, and simple preparation process. It is used in large-scale energy storage and other fields. It has good application value and development prospects.

However, the traditional zinc sulfate electrolyte used in zinc-ion batteries has problems such as slow zinc ion deposition/precipitation kinetics and low coulombic efficiency, which are manifested in low charge and discharge capacity and difficulty in rapid charging in the same battery system. The existing electrolyte for zinc-ion batteries still needs to be improved.

Public content

The present disclosure aims to solve one of the technical problems in the related art at least to a certain extent. To this end, one purpose of the present disclosure is to propose an electrolyte based on gelatin-manganese ion co-additive and its application. The electrolyte is low in cost, simple in process, safe and environmentally friendly, easy to be prepared on a large scale, and can effectively inhibit the growth of zinc dendrites and slow down the corrosion of the zinc negative electrode.

In one aspect of the present disclosure, the present disclosure proposes an electrolyte for zinc ion batteries. According to an embodiment of the present disclosure, the electrolyte includes gelatin, Zn ²⁺ , Mn ²⁺ and water.

The inventor found in the research on the electrolyte of the aqueous zinc ion battery that Mn ²⁺ as an electrolyte additive can significantly reduce the growth angle of zinc dendrites, and gelatin as an electrolyte additive can significantly inhibit the corrosion of the zinc anode. At the same time, gelatin and Mn ²⁺ show a synergistic effect in the electrolyte, and effectively inhibit the growth of each crystal face of zinc dendrites. Therefore, by using the electrolyte provided by the present disclosure, the cycle performance of the zinc ion battery can be significantly improved, and a major problem of zinc dendrite growth in the zinc ion battery can be overcome.

In addition, the electrolyte for the zinc ion battery according to the above-mentioned embodiments of the present disclosure may also have the following additional technical features:

In some embodiments of the present disclosure, the concentration of gelatin in the electrolyte is 0.2 to 1 wt%.

In some embodiments of the present disclosure, the ^{concentration of Zn 2+} in the electrolyte is 1.5-2.5 mol/L.

In some embodiments of the present disclosure, the ^{concentration of Mn 2+} in the electrolyte is 0.1-2 mol/L.

In some embodiments of the present disclosure, the Zn ²⁺ is provided in the form of ZnSO _4.

In some embodiments of the present disclosure, the Mn ²⁺ is provided in the form of MnSO _4.

In another aspect of the present disclosure, the present disclosure proposes a method for preparing the electrolyte for the zinc ion battery of the above-mentioned embodiment. According to an embodiment of the present disclosure, the method includes: mixing and heat-treating gelatin, a zinc ion solution, and a manganese ion solution to obtain the electrolyte. Therefore, the method is simple in process, safe and environmentally friendly, and easy to scale production.

In addition, the method for preparing an electrolyte for a zinc ion battery according to the foregoing embodiment of the present disclosure may also have the following additional technical features:

In some embodiments of the present disclosure, the heat treatment is performed at 0˜90° C. for 1˜24 hours to complete.

In another aspect of the present disclosure, the present disclosure proposes a zinc ion battery. According to an embodiment of the present disclosure, the zinc ion battery includes: the electrolyte of the above-mentioned embodiment. Therefore, the zinc-ion battery has all the features and advantages described above for the electrolyte used in the zinc-ion battery, and will not be repeated here. In general, the zinc ion battery has excellent cycle performance.

The additional aspects and advantages of the present disclosure will be partially given in the following description, and some will become obvious from the following description, or be understood through the practice of the present disclosure.

Description of the drawings

The above and/or additional aspects and advantages of the present disclosure will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, in which:

Figure 1 is a schematic diagram of the growth process of zinc dendrites in different electrolytes;

_{Figure 2 is a photo of 2M ZnSO 4} +0.2M MnSO ₄ mixed electrolyte containing different concentrations of gelatin;

Figure 3 is an electron micrograph of the morphology of zinc dendrites in different electrolytes;

Figure 4 shows the XRD results of different zinc anodes;

FIG. 5 is the cycle performance test results of the batteries prepared in Example 1, Comparative Examples 1 and 2.

Detailed ways

The embodiments of the present disclosure are described in detail below. The embodiments described below are exemplary, and are only used to explain the present disclosure, and should not be construed as limiting the present disclosure. Where specific techniques or conditions are not indicated in the examples, the procedures shall be carried out in accordance with the techniques or conditions described in the literature in the field or in accordance with the product specification. The reagents or instruments used without the manufacturer's indication are all conventional products that can be purchased commercially.

In one aspect of the present disclosure, the present disclosure proposes an electrolyte for zinc ion batteries. According to an embodiment of the present disclosure, the electrolyte includes gelatin, Zn ²⁺ , Mn ²⁺ and water.

The inventor found in the research on the electrolyte of the aqueous zinc ion battery that Mn ²⁺ as an electrolyte additive can significantly reduce the growth angle of zinc dendrites, and gelatin as an electrolyte additive can significantly inhibit the corrosion of the zinc anode. At the same time, gelatin and Mn ²⁺ show a synergistic effect in the electrolyte, and effectively inhibit the growth of each crystal plane of zinc dendrites. Therefore, by using the electrolyte provided by the present disclosure, the cycle performance of the zinc ion battery can be significantly improved, and a major problem of zinc dendrite growth in the zinc ion battery can be overcome.

The electrolyte used in the zinc ion battery according to the embodiments of the present disclosure will be further described in detail below.

According to some embodiments of the present disclosure, in the electrolyte of the present disclosure, the concentration of gelatin may be 0.2 to 1% by weight, such as 0.2% by weight, 0.3% by weight, 0.5% by weight, 0.7% by weight, 0.9% by weight, 1% by weight, etc. . The inventor found in the research that if the concentration of gelatin in the electrolyte is too low, it may not be able to effectively inhibit the formation of zinc dendrites and the corrosion of zinc metal. If the concentration of gelatin in the electrolyte is too high, manganese ions and zinc ions may precipitate out.

According to some embodiments of the present disclosure, in the electrolyte of the present disclosure, ^{the concentration of Zn 2+} may be 1.5 to 2.5 mol/L, for example, 1.5 mol/L, 1.75 mol/L, 2.0 mol/L, 2.25 mol/L , 2.5mol/L, etc. The inventor found in research that if the Zn ²⁺ concentration in the electrolyte is too low, it may promote the dissolution of the zinc anode. ^{If the concentration of Zn 2+} in the electrolyte is too high, the gelatin and manganese salt may not be fully dissolved.

According to some embodiments of the present disclosure, in the electrolyte of the present disclosure, ^{the concentration of Mn 2+} may be 0.1 to 2 mol/L, such as 0.1 mol/L, 0.15 mol/L, 0.2 mol/L, 0.25 mol/L, 0.3mol/L, 0.5mol/L, 1mol/L, 1.5mol/L, 2mol/L, etc. The inventor found in research that if the ^{concentration of Mn 2+} in the electrolyte is too low, the cycle performance of the battery may not be effectively improved. ^{If the concentration of Mn 2+} in the electrolyte is too high, precipitation may occur.

In the electrolyte of the present disclosure, ^{the specific provision form of Zn 2+} and Mn ²⁺ is not particularly limited, and traditional inorganic manganese salts, organic manganese salts, inorganic zinc salts, and organic zinc salts can be used according to actual needs. According to some embodiments of the present disclosure, Zn ²⁺ is provided in the form of ZnSO ₄ ^{and Mn 2+} is provided in the form of MnSO _4. As a result, the cost of the electrolyte is lower and the scope of application is wide.

In addition, the inventor took 2mol/L ZnSO ₄ electrolyte, 2mol/L ZnSO ₄ +0.2mol/L MnSO ₄ electrolyte, 2mol/L ZnSO ₄ +0.2mol/L MnSO ₄ + gelatin electrolyte as examples to study zinc The growth mechanism of dendrites with different electrolyte additives. Referring to Fig. 1, in the ZnSO ₄ electrolyte without any additives, the zinc dendrites mainly grow along the 30-70° direction and expose the (112) crystal plane. When manganese salt is added as an additive, zinc dendrites change the original deposition direction and crystal plane. It mainly grows along the direction of 0-30° and is dominated by (002) and (103) crystal planes. When manganese salt and gelatin are added as additives at the same time, the deposited zinc has lower crystallinity and no obvious dendritic characteristics.

In another aspect of the present disclosure, the present disclosure proposes a method for preparing the electrolyte for the zinc ion battery of the above-mentioned embodiment. According to an embodiment of the present disclosure, the method includes: mixing and heat-treating gelatin, a zinc ion solution, and a manganese ion solution to obtain the electrolyte. Therefore, the method is simple in process, safe and environmentally friendly, and easy to scale production.

Specifically, in the above preparation method, gelatin can be added to a mixed solution of zinc ions and manganese ions according to a predetermined concentration, and then subjected to heat treatment; or the gelatin can be dissolved in water and subjected to heat treatment, and then the resulting liquid can be mixed with The mixed solution of zinc ions and manganese ions can be mixed; gelatin can also be dissolved in water and heat-treated, then the insoluble matter in the liquid is removed, and then the solid zinc salt and manganese salt are dissolved in the obtained liquid according to a predetermined ratio.

According to an embodiment of the present disclosure, the above-mentioned heat treatment may be performed at 0˜90° C. for 1˜24 hours to complete. Specifically, the treatment temperature may be 0°C, 20°C, 40°C, 60°C, 80°C, 90°C, etc., and the treatment time may be 1h, 2h, 5h, 10h, 12h, 16h, 18h, 20h, 24h, etc. Preferably, the above-mentioned heat treatment can be completed at 20 to 60°C for 1 to 5 hours.

In another aspect of the present disclosure, the present disclosure proposes a zinc ion battery. According to an embodiment of the present disclosure, the zinc ion battery includes: the electrolyte of the above-mentioned embodiment. Therefore, the zinc-ion battery has all the features and advantages described above for the electrolyte used in the zinc-ion battery, which will not be repeated here. In general, the zinc ion battery has excellent cycle performance.

The following describes the present disclosure with reference to specific embodiments. It should be noted that these embodiments are only descriptive and do not limit the present disclosure in any way.

Example 1

(1) Dissolve 0.2～1% gelatin in 2M ZnSO ₄ +0.2M MnSO ₄ mixed electrolyte, heat and stir at 45°C for 2h, then cool it for later use; use different amounts of gelatin (0, 0.2%, 0.5%, 1%) ) The photo of the prepared electrolyte is shown in Figure 2.

(2) Battery assembly:

Positive electrode: aniline/MnO ₂ or ZnMn ₂ O ₄ ; negative electrode: zinc foil or zinc powder prepared by drawing slurry using a copper mesh current collector; diaphragm: preferably AGM diaphragm (adsorption glass fiber felt diaphragm).

After the AGM separator is fully immersed in the electrolyte containing the gelatin-manganese ion co-additive, the positive electrode aniline/MnO ₂ composite and the negative electrode Zn foil are combined to assemble the battery.

(3) Battery test: The capacity retention rate of the zinc ion battery after 1000 cycles at a current density of 500 mA/g is 80%, and the zinc dendritic morphology is shown in Figure 3a.

Example 2

(1) Dissolve 0.5% gelatin in deionized water, heat and stir at 55°C for 4 hours, and cool it for later use;

(2) Mix the liquid obtained in step (1) with 2M ZnSO ₄ +0.2M MnSO ₄ mixed electrolyte thoroughly and uniformly;

(3) Battery assembly:

Positive electrode: aniline/MnO ₂ or ZnMn ₂ O ₄ ; negative electrode: zinc foil or zinc powder prepared by drawing slurry using a copper mesh current collector; diaphragm: preferably AGM diaphragm (adsorption glass fiber felt diaphragm).

After the AGM separator is fully immersed in the electrolyte containing the gelatin-manganese ion co-additive, the positive electrode aniline/MnO ₂ composite and the negative electrode Zn foil are combined to assemble the battery.

(4) Battery test: The capacity retention rate of the zinc ion battery after 1000 cycles at a current density of 500 mA/g is 72%.

Example 3

(1) Dissolve 1% gelatin in deionized water, heat and stir at 65°C for 6 hours, and cool it for later use;

(2) Purify the liquid obtained in step (1) by centrifugation or suction filtration to remove insoluble materials to obtain a transparent and uniform liquid;

(3) _{Dissolve 2M ZnSO 4} +0.2M MnSO ₄ solid in the liquid obtained in step (2);

(4) Battery assembly:

Positive electrode: aniline/MnO ₂ or ZnMn ₂ O ₄ ; negative electrode: zinc foil or zinc powder prepared by drawing slurry using a copper mesh current collector; diaphragm: preferably AGM diaphragm (adsorption glass fiber felt diaphragm).

After the AGM separator is fully immersed in the electrolyte containing the gelatin-manganese ion co-additive, the positive electrode aniline/MnO ₂ composite and the negative electrode Zn foil are combined to assemble the battery.

(5) Battery test: The capacity retention rate of the zinc ion battery after 1000 cycles at a current density of 500 mA/g is 78%.

Comparative example 1

(1) _{Dissolve 2M ZnSO 4} in deionized water, heat and stir at 45°C for 2 hours, and cool it for later use;

(2) Battery assembly:

Positive electrode: aniline/MnO ₂ or ZnMn ₂ O ₄ ; negative electrode: zinc foil or zinc powder prepared by drawing slurry using a copper mesh current collector; diaphragm: preferably AGM diaphragm (adsorption glass fiber felt diaphragm).

After the AGM separator is fully immersed in the electrolyte containing the gelatin-manganese ion co-additive, the positive electrode aniline/MnO ₂ composite and the negative electrode Zn foil are combined to assemble the battery.

(3) Battery test: The capacity retention rate of the zinc ion battery after 1000 cycles at a current density of 500 mA/g is 4%, and the zinc dendritic morphology is shown in Figure 3b.

Comparative example 2

(1) Dissolve the manganese salt in 2M ZnSO ₄ electrolyte, heat and stir at 55°C for 4 hours, and cool it for later use;

(2) Battery assembly:

Positive electrode: aniline/MnO ₂ or ZnMn ₂ O ₄ ; negative electrode: zinc foil or zinc powder prepared by drawing slurry using a copper mesh current collector; diaphragm: preferably AGM diaphragm (adsorption glass fiber felt diaphragm).

After the AGM separator is fully immersed in the electrolyte containing the gelatin-manganese ion co-additive, the positive electrode aniline/MnO ₂ composite and the negative electrode Zn foil are combined to assemble the battery.

(3) Battery test: The capacity retention rate of the zinc ion battery after 1000 cycles at a current density of 500 mA/g is 33%, and the morphology of the zinc dendrite is shown in Figure 3c.

Comparative example 3

(1) Dissolve 0.2% gelatin in 2M ZnSO ₄ electrolyte, heat and stir at 45°C for 2 hours, and cool it for later use;

(2) Battery assembly:

Positive electrode: aniline/MnO ₂ or ZnMn ₂ O ₄ ; negative electrode: zinc foil or zinc powder prepared by drawing slurry using a copper mesh current collector; diaphragm: preferably AGM diaphragm (adsorption glass fiber felt diaphragm).

After the AGM separator is fully immersed in the electrolyte containing the gelatin-manganese ion co-additive, the positive electrode aniline/MnO ₂ composite and the negative electrode Zn foil are combined to assemble the battery.

(3) Battery test: The capacity retention rate of the zinc ion battery after 1000 cycles at a current density of 500 mA/g is 28%.

In the above examples and comparative examples, the XRD results of different zinc anodes are shown in Figure 4; and the battery cycle performance is shown in Figure 5. In Figure 4, Normalized Intensity represents normalized intensity, 2Theta represents 2θ angle, and Gelatin represents gelatin. The test results show that gelatin and manganese ions in the electrolyte can have a synergistic effect, thereby significantly improving the cycle performance of the zinc-ion battery.

Claims (9)

1. An electrolyte for a zinc ion battery, which is characterized by comprising: gelatin, Zn ²⁺ , Mn ²⁺ and water.
2. The electrolyte according to claim 1, wherein the concentration of gelatin in the electrolyte is 0.2 to 1 wt%.
3. The electrolyte according to any one of claims 1 to 2, wherein ^{the concentration of Zn 2+} in the electrolyte is 1.5 to 2.5 mol/L.
4. The electrolyte according to any one of claims 1 to 3, wherein ^{the concentration of Mn 2+} in the electrolyte is 0.1 to 2 mol/L.
5. The electrolyte according to any one of claims 1 to 4, wherein the Zn ²⁺ is provided in the form of ZnSO _4.
6. The electrolyte according to any one of claims 1 to 5, wherein the Mn ²⁺ is provided in the form of MnSO _4.
7. A method for preparing the electrolyte according to any one of claims 1 to 6, characterized in that it comprises:

   The gelatin, the zinc ion solution and the manganese ion solution are mixed and heat-treated to obtain the electrolyte.
8. The method according to claim 7, wherein the heat treatment is completed at 0-90°C for 1-24 hours.
9. A zinc ion battery, characterized by comprising: the electrolyte according to any one of claims 1 to 6.

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