CN115911596B - Zinc metal battery electrolyte and preparation method and application thereof - Google Patents

Abstract

The invention discloses zinc metal battery electrolyte and a preparation method and application thereof. Relates to the technical field of zinc metal batteries. An electrolyte comprising the following components: a zinc source; a solvent, and the solvent does not include ethylene glycol; ethylene glycol; the volume ratio of the solvent to the glycol is 52-99.75:0.25-48. Compared with the electrolyte without adding glycol, the electrolyte provided by the invention can effectively improve the cycle stability of the zinc metal battery under the conditions of high concentration and low concentration of glycol content.

Description

A kind of zinc metal battery electrolyte and its preparation method and application

technical field

The invention relates to the technical field of zinc metal batteries, in particular to an electrolyte solution for zinc metal batteries and a preparation method and application thereof.

Background technique

With the growing demand for energy and awareness of climate change, there is an urgent need to facilitate and accelerate the transition from fossil fuels to clean, renewable energy. Among the numerous electrochemical energy storage devices. Batteries have attracted extensive attention because they can be used not only as the basic unit for stable power of electronic equipment, but also as an energy storage device for grid energy storage.

Among many battery systems, lithium-ion batteries are widely used in various fields due to their high energy density and long cycle life. However, the scarcity of lithium resources and the use of flammable organic electrolytes seriously hinder the further development of lithium-ion batteries in the field of large-scale storage. In order to reduce the cost of energy storage batteries, people began to explore and develop other energy storage batteries.

Among them, aqueous zinc metal batteries have attracted extensive attention due to their advantages such as high volume specific capacity, high reserves of zinc resources, and the flame retardancy of the electrolyte. However, problems such as dendrites, corrosion, and hydrogen production in the zinc sheet anode during the cycle have greatly hindered its actual production and application.

Therefore, further research is needed to improve the overall performance of Zn batteries.

Contents of the invention

The first technical problem to be solved by the present invention is:

An electrolyte is provided.

The second technical problem to be solved by the present invention is:

A method for preparing the electrolyte is provided.

The third technical problem to be solved by the present invention is:

Application of the electrolyte.

In order to solve the first technical problem, the technical solution adopted in the present invention is:

An electrolyte comprising the following components:

Zinc source;

solvent;

ethylene glycol;

The volume ratio of the solvent to the ethylene glycol is 52-99.75:0.25-48.

According to the embodiments of the present invention, one of the technical solutions has at least one of the following advantages or beneficial effects:

Compared with the electrolytic solution without ethylene glycol, the electrolytic solution of the present invention can effectively improve the cycle stability performance of the zinc metal battery at both high and low concentrations of ethylene glycol. Among them, when the volume of ethylene glycol is small, it can achieve the effect of suppressing dendrites through specific tip adsorption, avoiding the accumulation of electrons at the tip, thereby avoiding the problem of hydrogen production caused by the accumulation of electrons and leaving behind after hydrogen production. A large number of hydroxide ions, these hydroxide ions and zinc ions will precipitate, which will lead to the passivation of the surface of the zinc sheet negative electrode. Among them, when the volume of ethylene glycol is large, a series of side reactions involving the solvent will be suppressed at a high concentration, thereby achieving the effect of improving battery life.

According to one embodiment of the present invention, the zinc source includes at least one of zinc sulfate, zinc acetate, zinc trifluoromethanesulfonate, zinc chloride and zinc perchlorate.

According to one embodiment of the present invention, the molar concentration of the zinc source in the electrolyte is 1-2 mol/L.

According to one embodiment of the present invention, the molar concentration of the zinc source in the electrolyte is 1-1.5 mol/L.

According to one embodiment of the present invention, the molar concentration of the zinc source in the electrolyte is 0.5-1.5 mol/L.

According to one embodiment of the present invention, the volume ratio of the solvent to the ethylene glycol is 52-60:0.25-1.

According to one embodiment of the present invention, the volume ratio of the solvent to the ethylene glycol is 52-60:1-48.

Electrolyte of the present invention comprises zinc source, solvent and ethylene glycol, after the consumption of zinc source is determined, by adjusting the volume ratio of described solvent and described ethylene glycol, can adjust zinc source and ethylene glycol in electrolytic solution concentration in . However, the electrolyte solution of the present invention can effectively inhibit the dendrite growth of the negative electrode at a low concentration, and can effectively inhibit active water from participating in a series of side reactions at a high concentration, thereby significantly improving the cycle performance of the zinc metal battery and prolonging the service life.

In order to solve the second technical problem, the technical solution adopted in the present invention is:

A method for preparing the electrolyte, comprising the steps of:

The zinc source and ethylene glycol are mixed in a solvent to obtain the electrolyte.

The method for preparing the electrolyte of the present invention has simple process and easy operation, and is suitable for industrial large-scale production and application.

According to an embodiment of the present invention, there is also provided a zinc metal battery, including a positive electrode, a negative electrode, an electrode solution and a separator, wherein the electrode solution includes the above-mentioned electrolyte solution.

According to one embodiment of the present invention, in the battery, the electrolyte solution is used in an amount of 150-220 μL.

According to one embodiment of the present invention, in the battery, the electrolyte solution is used in an amount of 180-200 μL.

According to one embodiment of the present invention, the positive electrode includes a vanadium disulfide pole piece.

According to one embodiment of the present invention, the negative electrode includes zinc foil.

According to one embodiment of the present invention, the membrane comprises a glass fiber membrane.

According to one embodiment of the present invention, in the battery, the zinc foil is used as the working electrode, and the zinc foil is used as the counter/reference electrode.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and understandable from the description of the embodiments in conjunction with the following drawings, wherein:

Fig. 1 is the cycle performance figure of embodiment 1-2 and comparative example 1 preparation half cell;

Fig. 2 is the cycle performance diagram of the full battery prepared in Example 1-2 and Comparative Example 1;

Fig. 3 is the statistical diagram of the electric double layer capacitance of the electrode prepared in embodiment 1 and comparative example 1 half cell;

Fig. 4 is the X-ray diffraction pattern of the product on the surface of the zinc electrode after 50 cycles of Example 2 and Comparative Example 1.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of the present invention.

The reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field unless otherwise specified.

Example 1

An electrolyte comprising the following components:

zinc sulfate;

water;

ethylene glycol;

The volume ratio of the above water to the above ethylene glycol is 99.75:0.25;

The concentration of zinc sulfate is 2mol/L ZnSO ₄ .

Prepare above-mentioned electrolytic solution, comprise the following steps:

Mix deionized water and ethylene glycol at a volume ratio of 99.75:0.25, then add zinc sulfate until the concentration of zinc sulfate in the electrolyte reaches 2mol/L, stir the solution with a magnetic stirrer until the solution becomes transparent, and obtain the above electrolyte.

A zinc foil with a diameter of 12mm is used as the working electrode, a 12mm zinc foil is used as the counter/reference electrode, and a battery is assembled with a glass fiber separator and a standard CR2032 battery case. Each battery uses 180 μL of the above electrolyte to obtain a zinc battery .

In the electrolyte solution of Example 1, when the volume of ethylene glycol is small, it can achieve the effect of suppressing dendrites through specific tip adsorption, avoiding the accumulation of electrons at the tip, thereby avoiding the problem of hydrogen production and the production of hydrogen caused by the accumulation of electrons. A large number of hydroxide ions are left after the hydrogen, and these hydroxide ions and zinc ions precipitate, which will lead to the passivation of the surface of the negative electrode of the zinc sheet.

Example 2

The difference between embodiment 2 and embodiment 1 is that the volume ratio of water to ethylene glycol is different. Wherein, the volume ratio of water in Example 2 to the above-mentioned ethylene glycol is 60:40. Wherein, the volume ratio of water in Example 1 to the above-mentioned ethylene glycol is 99.75:0.25.

An electrolyte comprising the following components:

zinc sulfate;

water;

ethylene glycol;

The volume ratio of the above water to the above ethylene glycol is 60:40;

The concentration of zinc sulfate is 2mol/L ZnSO ₄ .

Prepare above-mentioned electrolytic solution, comprise the following steps:

The volume ratio is 60:40.

Prepare above-mentioned electrolytic solution, comprise the following steps:

Mix deionized water and ethylene glycol at a volume ratio of 60:40, then add zinc sulfate until the concentration of zinc sulfate in the electrolyte reaches 2mol/L, stir the solution with a magnetic stirrer until the solution becomes transparent, and obtain the above electrolyte.

A zinc foil with a diameter of 12mm is used as the working electrode, a 12mm zinc foil is used as the counter/reference electrode, and a battery is assembled with a glass fiber separator and a standard CR2032 battery case. Each battery uses 180 μL of the above electrolyte to obtain a zinc battery .

In Example 2, the volume of ethylene glycol is relatively large, and high-concentration ethylene glycol will suppress the problem of a series of side reactions in which the solvent participates, avoiding the production of by-products, such as Zn ₄ (OH) ₆ SO ₄ ·5H ₂ O, Thereby, the effect of improving battery life is achieved.

Example 3

The difference between Embodiment 3 and Embodiment 1 lies in that the battery structure is different. Among them, the battery of Example 3 includes a copper foil with a diameter of 12mm and deposited a certain amount of zinc as the negative electrode (the positive and negative electrode capacity ratio is 1:5), and a 12mm VS ₂ pole piece is used as the positive electrode. Wherein, the battery of Example 1 includes a zinc foil with a diameter of 12 mm as the working electrode, a 12 mm zinc foil as the counter/reference electrode, a glass fiber separator and a standard CR2032 battery case to assemble the battery. Wherein, the loading amount of zinc deposited on the copper foil is about 2.85 mg/cm ² .

An electrolyte comprising the following components:

zinc sulfate;

water;

ethylene glycol;

The volume ratio of the above water to the above ethylene glycol is 99.75:0.25;

The concentration of zinc sulfate is 2mol/L ZnSO ₄ .

Prepare above-mentioned electrolytic solution, comprise the following steps:

Mix deionized water and ethylene glycol at a volume ratio of 99.75:0.25, then add zinc sulfate until the concentration of zinc sulfate in the electrolyte reaches 2mol/L, stir the solution with a magnetic stirrer until the solution becomes transparent, and obtain the above electrolyte.

The copper foil with a diameter of 12mm and deposited a certain amount of zinc is used as the negative electrode (the capacity ratio of positive and negative electrodes is 1:5), and the 12mm VS ₂ pole piece is used as the positive electrode, and the battery is assembled with a glass fiber separator and a standard CR2032 battery case. 180 μL of the above electrolyte solution was used for each battery to obtain a zinc battery.

Example 4

The difference between Embodiment 4 and Embodiment 2 lies in that the battery structure is different. Among them, the battery of Example 4 includes a copper foil with a diameter of 12mm and deposited a certain amount of zinc as the negative electrode (the positive and negative electrode capacity ratio is 1:5), and a 12mm VS ₂ pole piece is used as the positive electrode. Among them, the battery of Example 4 includes a copper foil with a diameter of 12mm and deposited a certain amount of zinc as the negative electrode (the positive and negative electrode capacity ratio is 1:5), and a 12mm VS ₂ pole piece is used as the positive electrode. Wherein, the battery of Example 1 includes a zinc foil with a diameter of 12 mm as the working electrode, a 12 mm zinc foil as the counter/reference electrode, a glass fiber separator and a standard CR2032 battery case to assemble the battery. Wherein, the loading amount of zinc deposited on the copper foil is about 2.85 mg/cm ² .

An electrolyte comprising the following components:

zinc sulfate;

water;

ethylene glycol;

The volume ratio of the above water to the above ethylene glycol is 60:40;

The concentration of zinc sulfate is 2mol/L ZnSO ₄ .

Prepare above-mentioned electrolytic solution, comprise the following steps:

The volume ratio is 60:40.

Prepare above-mentioned electrolytic solution, comprise the following steps:

Mix deionized water and ethylene glycol at a volume ratio of 60:40, then add zinc sulfate until the concentration of zinc sulfate in the electrolyte reaches 2mol/L, stir the solution with a magnetic stirrer until the solution becomes transparent, and obtain the above electrolyte.

The copper foil with a diameter of 12mm and deposited a certain amount of zinc is used as the negative electrode (the capacity ratio of positive and negative electrodes is 1:5), and the 12mm VS ₂ pole piece is used as the positive electrode, and the battery is assembled with a glass fiber separator and a standard CR2032 battery case. 180 μL of the above electrolyte solution was used for each battery to obtain a zinc battery. Wherein, the loading amount of zinc deposited on the copper foil is about 2.85 mg/cm ² .

Comparative example 1

The difference between Comparative Example 1 and Example 1 is that the volume ratio of water to ethylene glycol is different. Wherein, the volume ratio of water to ethylene glycol in Comparative Example 1 is 100:0. Wherein, the volume ratio of water in Example 1 to the above-mentioned ethylene glycol is 99.75:0.25.

An electrolyte comprising the following components:

zinc sulfate;

water;

ethylene glycol;

The volume ratio of the above water to the above ethylene glycol is 99.75:0.25;

The concentration of zinc sulfate is 2mol/L ZnSO ₄ .

Prepare above-mentioned electrolytic solution, comprise the following steps:

Mix deionized water and ethylene glycol at a volume ratio of 99.75:0.25, then add zinc sulfate until the concentration of zinc sulfate in the electrolyte reaches 2mol/L, stir the solution with a magnetic stirrer until the solution becomes transparent, and obtain the above electrolyte.

A zinc foil with a diameter of 12mm is used as the working electrode, a 12mm zinc foil is used as the counter/reference electrode, and a battery is assembled with a glass fiber separator and a standard CR2032 battery case. Each battery uses 180 μL of the above electrolyte to obtain a zinc battery .

Comparative example 2

The difference between Comparative Example 2 and Comparative Example 1 lies in that the battery structure is different. Among them, the battery of Comparative Example 2 includes a copper foil with a diameter of 12mm and deposited a certain amount of zinc as the negative electrode (the positive and negative electrode capacity ratio is 1:5), and a 12mm VS ₂ pole piece is used as the positive electrode. The battery of Comparative Example 1 included a 12 mm diameter zinc foil as a working electrode and a 12 mm zinc foil as a counter/reference electrode. Wherein, the loading amount of zinc deposited on the copper foil is about 2.85 mg/cm ² .

An electrolyte comprising the following components:

zinc sulfate;

water;

ethylene glycol;

The volume ratio of the above water to the above ethylene glycol is 99.75:0.25;

The concentration of zinc sulfate is 2mol/L ZnSO ₄ .

Prepare above-mentioned electrolytic solution, comprise the following steps:

Mix deionized water and ethylene glycol at a volume ratio of 99.75:0.25, then add zinc sulfate until the concentration of zinc sulfate in the electrolyte reaches 2mol/L, stir the solution with a magnetic stirrer until the solution becomes transparent, and obtain the above electrolyte.

The copper foil with a diameter of 12mm and deposited a certain amount of zinc is used as the negative electrode (the capacity ratio of positive and negative electrodes is 1:5), and the 12mm VS ₂ pole piece is used as the positive electrode, and the battery is assembled with a glass fiber separator and a standard CR2032 battery case. 180 μL of the above electrolyte solution was used for each battery to obtain a zinc battery.

test case 1

Examples 1-2 of the present invention and Comparative Example 1 were made into half-cell samples, and the cycle stability of the half-cell was tested (the test system used Xinwei battery charge and discharge tester). Fig. 1 is the cycle performance test graph of the half-cell samples of Examples 1-2 and Comparative Example 1, the test conditions are current density 2mA/cm ² , galvanostatic deposition-electrolytic capacity 2mAh/cm ² , and the cycle performance test is carried out.

As shown in Fig. 1, the half-cells made by Examples 1-2 can run stably for 2400h and 1730h respectively. However, the half-cell made of Comparative Example 1 short-circuited after 90 hours, and then the battery failed. This shows that ethylene glycol can effectively improve battery life at both high and low concentrations, showing excellent results.

test case 2

Examples 3-4 of the present invention and Comparative Example 2 were prepared as full battery samples, and the cycle life of the full battery was tested (the test system used Xinwei battery charge and discharge tester). FIG. 2 is a cycle performance test chart of the full battery samples of Examples 3-4 and Comparative Example 2. The test condition is a current density of 1A/g, and the cycle performance test is performed.

As shown in FIG. 2 , the full batteries made in Examples 3 and 4 can maintain a capacity retention rate of 82.7% and 98.4%, respectively, after 650 cycles of stable operation. However, the capacity of the full battery made in Comparative Example 2 dropped significantly after 165 cycles, indicating that a short circuit occurred in the battery, which also showed that Examples 3-4 effectively improved the performance of the zinc metal battery.

Test case 3

Example 1 of the present invention and Comparative Example 1 were made into half-cell samples, and the electric double layer capacitance on the electrode surface was tested (the test system was Chenhua Electrochemical Workstation). Fig. 3 is a statistical diagram of the electric double layer capacitance on the electrode surface of the half-cell samples of Example 1 and Comparative Example 1, using cyclic voltammetry, the test range is -0.015-0.015V, and the scan rate is 12-20mV.

As shown in Figure 3, the electric double layer capacitance on the electrode surface of Example 1 is significantly lower than that of Comparative Example 1, indicating that ethylene glycol is adsorbed on the electrode surface, thereby guiding the uniform deposition of zinc ions.

Test case 4

Example 2 of the present invention and comparative example 1 were made into half-cell samples, and after 50 cycles at a current density of 5 mA/cm ² and a constant current deposition-electrolytic capacity of 2 mAh/cm ² , the surface of the zinc foil was formed by X-ray diffraction. Qualitative analysis was carried out.

As shown in Figure 4, through the XRD test pattern, the signal (corresponding to the peak of 8 degrees) of the surface by-product Zn ₄ (OH) ₆ SO ₄ 5H ₂ O in Example 2 is significantly lower than that of Comparative Example 1, which shows that Example 2 is for The production of by-products can be significantly inhibited, which can improve battery performance.

The above are only examples of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent transformations made by using the content of the description of the present invention, or directly or indirectly used in related technical fields, are equally included in the patent protection of the present invention. within range.

Claims (7)

1. a zinc metal battery electrolyte, is characterized in that: comprise following component: Zinc source; a solvent, and the solvent does not include ethylene glycol; ethylene glycol; The solvent is water, and the volume ratio of water to the ethylene glycol is 99.75:0.25; The zinc source includes at least one of zinc sulfate, zinc acetate, zinc trifluoromethanesulfonate, zinc chloride and zinc perchlorate. 2. A zinc metal battery electrolyte according to claim 1, characterized in that: the molar concentration of the zinc source in the electrolyte is 1-2 mol/L. 3. a method for preparing a kind of zinc metal battery electrolyte as described in any one of claims 1 to 2, is characterized in that: comprise the following steps: The zinc source and ethylene glycol are mixed in a solvent to obtain the electrolyte. 4. A zinc metal battery, characterized in that: comprising a positive pole, a negative pole, a diaphragm and a zinc metal battery electrolyte according to any one of claims 1 to 2. 5. The zinc metal battery according to claim 4, wherein the positive electrode comprises a vanadium disulfide pole piece. 6. The zinc metal battery of claim 4, wherein the negative electrode comprises zinc foil. 7. The zinc metal battery of claim 4, wherein the separator comprises a glass fiber separator.