A negative electrode for a zinc-nickel battery and its preparation method

Abstract

This application discloses a negative electrode for a zinc-nickel battery and its preparation method. The negative electrode includes a zinc foil and an interface layer covering the surface of the zinc foil. The preparation method of the polymer artificial solid electrolyte interface layer is simple and has a high yield. The material can be uniformly spin-coated onto the zinc foil by spin coating. The polymer artificial solid electrolyte interface layer improves the stability and cycle performance of the zinc negative electrode of the alkaline zinc-nickel battery.

Description

Technical Field

[0001] This application relates to a negative electrode for a zinc-nickel battery and its preparation method, belonging to the field of zinc-nickel batteries. Background Technology

[0002] With the booming development of electric vehicles, microelectronics, and grid energy storage, the demand for high-performance and safe rechargeable batteries is becoming increasingly urgent. Alkaline zinc-nickel batteries, in particular, possess advantages such as high safety, low cost, high power density, environmental friendliness, and high energy density, and hold promise as a replacement for lead-acid, nickel-cadmium, nickel-metal hydride, and even lithium-ion batteries. However, zinc-nickel batteries currently face many limitations. The discharge products of the negative electrode material in zinc-nickel batteries are easily soluble in alkaline electrolytes. During charge and discharge, the zinc negative electrode suffers from problems such as deformation, dendrite formation, passivation, and self-corrosion, leading to reduced battery cycle life and thus hindering the industrialization of zinc-nickel batteries. Therefore, the stability of the zinc negative electrode is crucial to the performance of alkaline zinc-nickel batteries and remains a hot research topic and a significant challenge. Summary of the Invention

[0003] The purpose of this invention is to design a polymer-based artificial solid electrolyte interface layer on the surface of the zinc anode to improve the stability and cycle performance of the zinc anode in alkaline zinc-nickel batteries. This invention provides a method for preparing the artificial solid electrolyte interface layer, which is then spin-coated onto the surface of zinc foil. This reduces the occurrence of side reactions and inhibits dendrite growth, thereby improving the cycle performance of the zinc-nickel battery.

[0004] According to one aspect of this application, a negative electrode for a zinc-nickel battery is provided, the negative electrode comprising a zinc foil and an interface layer covering the surface of the zinc foil;

[0005] The interface layer contains a substance with the structure shown in Formula I:

[0006]

[0007] The thickness of the interface layer on the zinc foil surface is 15–20 μm.

[0008] According to another aspect of this application, a method for preparing the negative electrode of the above-mentioned zinc-nickel battery is provided, comprising the following steps:

[0009] (1) Mix the raw materials containing o-toluidine, dimethoxymethane and trifluoroacetic acid, heat them, then mix them with ammonia water I, precipitate, separate, wash and obtain intermediate product I;

[0010] (2) The intermediate product I was mixed with chloroform, methanol and iodomethane, reacted, separated and washed to obtain intermediate product II;

[0011] (3) Mix the intermediate product II with ammonia water II, separate and wash to obtain the substance with the structure shown in Formula I;

[0012] (4) The substance with the structure shown in Formula I is mixed with N,N-dimethylacetamide to obtain a spin coating solution, and the spin coating solution is spin coated on the surface of zinc foil to obtain the negative electrode of the zinc-nickel battery.

[0013] (1)

[0014] The mass ratio of o-toluidine to dimethoxymethane is 1:1 to 1:2;

[0015] The mass ratio of o-toluidine to trifluoroacetic acid is 1:10 to 1:15;

[0016] The heating temperature is 25–30°C;

[0017] The heating time is 96–100 hours;

[0018] The ratio of o-toluidine to ammonia I is 1:40 to 1:50.

[0019] The process of mixing the raw materials containing o-toluidine, dimethoxymethane and trifluoroacetic acid is carried out in an ice-water bath, cooling to 0°C.

[0020] (2)

[0021] The ratio of intermediate product I to chloroform is 1:80 to 1:90.

[0022] The ratio of intermediate product I to methanol is 1:40 to 1:50.

[0023] The ratio of intermediate product I to iodomethane is 1:1 to 1:5.

[0024] (3)

[0025] The ratio of intermediate product II to ammonia water II is 1:10 to 1:20.

[0026] (4)

[0027] The ratio of the substance with the structure shown in Formula I to the N,N-dimethylacetamide is 1:90 to 1:100;

[0028] The diameter of the spin coating is 12-15 mm;

[0029] The volume of the spin coating solution used for spin coating is 20–25 μL.

[0030] The separation is centrifugal separation.

[0031] The washing solution used for washing is selected from at least one of water, methanol, ethanol, and acetone.

[0032] Specifically, it includes the following steps:

[0033] (1) Add dimethoxymethane (DMM) to o-toluidine, and then place the reaction in an ice-water bath;

[0034] (2) Add the mixture from (1) to trifluoroacetic acid (TFA);

[0035] (3) Heat and stir the mixture obtained in (2);

[0036] (4) After the reaction in (3) is complete, pour the resulting viscous solution into a vigorously stirred ammonia solution;

[0037] (5) The precipitate obtained in (4) is separated by centrifugation and washed sequentially with excess deionized water, methanol and acetone.

[0038] (6) Dissolve the product obtained in (5) in chloroform solution;

[0039] (7) Slowly add the solution obtained in (6) to methanol to precipitate the precipitate, then centrifuge and dry;

[0040] (8) Disperse the product obtained in (7) in methanol and treat it with excess iodomethane, then stir it in the dark at room temperature;

[0041] (9) Separate the product from (8) by centrifugation, wash it with methanol and deionized water, and finally dry it.

[0042] (10) Disperse the product obtained in (9) in ammonia water and stir in the dark;

[0043] (11) Separate (10) by centrifugation, then wash with ethanol and deionized water in sequence, and finally dry;

[0044] (12) Dissolve the product of (11) in N,N-dimethylacetamide and then spin coat it onto zinc foil.

[0045] The synthetic route for the substance with the structure shown in Formula I is as follows:

[0046]

[0047] The beneficial effects that this application can produce include:

[0048] (1) The preparation method of the polymer artificial solid electrolyte interface layer is simple and has a high yield;

[0049] (2) The material can be uniformly spin-coated onto zinc foil by spin coating;

[0050] (3) The polymer artificial solid electrolyte interface layer improves the stability and cycle performance of the zinc anode of alkaline zinc-nickel batteries. Attached Figure Description

[0051] Figure 1 The time-voltage curve of the Zn||Zn symmetric cell prepared in Example 1 in 6M KOH solution is shown. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Elements and features described in one embodiment of the present invention can be combined with elements and features shown in one or more other embodiments. It should be noted that, for clarity, representations and descriptions of components and processes unrelated to the present invention and known to those skilled in the art are omitted in the description. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0053] The present invention relates to a polymer artificial solid electrolyte interface layer designed on the surface of the zinc anode. The synthesis steps are simple and can effectively improve the stability and cycle performance of the zinc anode in alkaline zinc-nickel batteries.

[0054] Example 1:

[0055] Dimethoxymethane (DMM, 4.28 mL) was added to o-toluidine (2.040 g), and then the mixture was cooled to 0 °C in an ice-water bath before adding trifluoroacetic acid (TFA, 16.16 mL). The final mixture was then heated to room temperature (25 °C) and stirred for 96 h. After the reaction was complete, the resulting viscous solution was poured into a vigorously stirred ammonium aqueous solution, resulting in precipitation. The product was separated by centrifugation and washed successively with excess deionized water, methanol, and acetone. The product was purified three times by repeated precipitation: first, the product was dissolved in chloroform solution, then slowly added to methanol to precipitate the product, followed by centrifugation and drying. The pre-formed polymer (1 g) was dispersed in methanol (10 mL) and treated with excess iodomethane (1 g) under continuous stirring at room temperature in the dark for 24 h. The product was then separated by centrifugation, washed with methanol and water, and finally dried. Then, 1g of the product was weighed and dispersed in 10mL of ammonia water, stirred in the dark for 24 hours, and then separated by centrifugation. The product was then washed three times with ethanol and deionized water, and finally dried to obtain the final polymer. 50mg of the product was weighed and dissolved in 1mL of N,N-dimethylacetamide, and then 25μL was drop-coated onto a zinc foil disc with a diameter of 15mm to prepare a zinc anode.

[0056] Alkaline zinc-nickel symmetrical battery assembly:

[0057] Assembly: The negative electrode with an artificial solid electrolyte interface layer was used as the electrode of the symmetrical battery, GF-D was used as the separator, 6M KOH was used as the electrolyte, and the battery was assembled into a coin cell under a pressure of 0.9T. Constant current charge and discharge tests were performed using the Land battery testing system.

[0058] Alkaline zinc-nickel battery full cell assembly:

[0059] Assembly: Using nickel hydroxyl oxide as the positive electrode, zinc foil with an artificial solid electrolyte interface layer as the negative electrode, CLY140PP as the separator, and 6M KOH as the electrolyte, a coin cell was assembled at a pressure of 0.9T and constant current charge-discharge test was performed using the Land battery testing system.

[0060] Figure 1 The image shows the time-voltage curves of the Zn||Zn symmetric cell prepared in Example 1 in 6M KOH solution. It is clearly shown that the cycle life of the Zn||Zn symmetric cell with the polymer artificial solid electrolyte interface layer spin-coated is significantly improved, and the polarization is significantly reduced compared to the symmetric cell with pure zinc sheet.

[0061] Example 2:

[0062] Dimethoxymethane (DMM, 4.28 mL) was added to o-toluidine (2.040 g), and then the mixture was cooled to 0 °C in an ice-water bath before adding trifluoroacetic acid (TFA, 16.16 mL). The final mixture was then heated to room temperature (25 °C) and stirred for 96 h. After the reaction was complete, the resulting viscous solution was poured into a vigorously stirred ammonium aqueous solution, resulting in precipitation. The product was separated by centrifugation and washed successively with excess deionized water, methanol, and acetone. The product was purified three times by repeated precipitation: first, the product was dissolved in chloroform solution, then slowly added to methanol to precipitate the product, followed by centrifugation and drying. The pre-formed polymer (1 g) was dispersed in methanol (10 mL) and treated with excess iodomethane (1 g) under continuous stirring at room temperature in the dark for 24 h. The product was then separated by centrifugation, washed with methanol and water, and finally dried. Then, 1g of the product was weighed and dispersed in 10mL of ammonia water, stirred in the dark for 24 hours, and then separated by centrifugation. The product was then washed three times with ethanol and deionized water, and finally dried to obtain the final polymer. 50mg of the product was weighed and dissolved in 1mL of N,N-dimethylacetamide, and then 15μL was dropped onto a zinc foil disc with a diameter of 15mm to prepare a zinc anode.

[0063] Alkaline zinc-nickel symmetrical battery assembly:

[0064] Assembly: The negative electrode with an artificial solid electrolyte interface layer spin-coated is used as the electrode of the symmetrical battery, GF-D is used as the separator, 6M KOH is used as the electrolyte, and the battery is assembled into a coin cell under a pressure of 0.9T. Constant current charge and discharge tests are performed using the Land battery testing system.

[0065] Alkaline zinc-nickel battery full cell assembly:

[0066] Assembly: Using nickel hydroxy oxide as the positive electrode, zinc foil with an artificial solid electrolyte interface layer spin-coated as the negative electrode, CLY140PP as the separator, and 6M KOH as the electrolyte, a coin cell was assembled at a pressure of 0.9T and constant current charge-discharge test was performed using the Land battery testing system.

[0067] Example 3:

[0068] Dimethoxymethane (DMM, 4.28 mL) was added to o-toluidine (2.040 g), and then the mixture was cooled to 0 °C in an ice-water bath before adding trifluoroacetic acid (TFA, 16.16 mL). The final mixture was then heated to room temperature (25 °C) and stirred for 96 h. After the reaction was complete, the resulting viscous solution was poured into a vigorously stirred ammonium aqueous solution, resulting in precipitation. The product was separated by centrifugation and washed successively with excess deionized water, methanol, and acetone. The product was purified three times by repeated precipitation: first, the product was dissolved in chloroform solution, then slowly added to methanol to precipitate the product, followed by centrifugation and drying. The pre-formed polymer (1 g) was dispersed in methanol (10 mL) and treated with excess iodomethane (1 g) under continuous stirring at room temperature in the dark for 24 h. The product was then separated by centrifugation, washed with methanol and water, and finally dried. Then, 1g of the product was weighed and dispersed in 10mL of ammonia water, stirred in the dark for 24h, separated by centrifugation, washed three times with ethanol and deionized water, and finally dried to obtain the final polymer P1. 50mg of the product was weighed and dissolved in 1mL of N,N-dimethylacetamide, and then 35μL was drop-coated onto a zinc foil disc with a diameter of 15mm to prepare a zinc anode.

[0069] Alkaline zinc-nickel symmetrical battery assembly:

[0070] Assembly: The negative electrode with an artificial solid electrolyte interface layer was used as the electrode of the symmetrical battery, GF-D was used as the separator, 6M KOH was used as the electrolyte, and the battery was assembled into a coin cell under a pressure of 0.9T. Constant current charge and discharge tests were performed using the Land battery testing system.

[0071] Alkaline zinc-nickel battery full cell assembly:

[0072] Assembly: Using nickel hydroxy oxide as the positive electrode, zinc foil with an artificial solid electrolyte interface layer spin-coated as the negative electrode, CLY140PP as the separator, and 6M KOH as the electrolyte, a coin cell was assembled at a pressure of 0.9T and constant current charge-discharge test was performed using the Land battery testing system.

[0073] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A negative electrode for a zinc-nickel battery, characterized in that, The negative electrode includes a zinc foil and an interface layer covering the surface of the zinc foil; The interface layer contains a substance with the structure shown in Formula I:

2. The negative electrode according to claim 1, characterized in that, The thickness of the interface layer on the zinc foil surface is 15–20 μm.

3. A method for preparing the negative electrode of a zinc-nickel battery according to any one of claims 1 or 2, characterized in that, Includes the following steps: (1) Mix the raw materials containing o-toluidine, dimethoxymethane and trifluoroacetic acid, heat them, then mix them with ammonia water I, precipitate, separate, wash and obtain intermediate product I; (2) The intermediate product I was mixed with chloroform, methanol and iodomethane, reacted, separated and washed to obtain intermediate product II; (3) Mix the intermediate product II with ammonia water II, separate and wash to obtain the substance with the structure shown in Formula I; (4) The substance with the structure shown in Formula I is mixed with N,N-dimethylacetamide to obtain a spin coating solution, and the spin coating solution is spin coated on the surface of zinc foil to obtain the negative electrode of the zinc-nickel battery.

4. The preparation method according to claim 3, characterized in that, (1) The mass ratio of o-toluidine to dimethoxymethane is 1:1 to 1:2; The mass ratio of o-toluidine to trifluoroacetic acid is 1:10 to 1:15; The heating temperature is 25–30°C; The heating time is 96–100 hours; The ratio of o-toluidine to ammonia I is 1:40 to 1:

50.

5. The preparation method according to claim 3, characterized in that, (2) The ratio of intermediate product I to chloroform is 1:80 to 1:

90. The ratio of intermediate product I to methanol is 1:40 to 1:

50. The ratio of intermediate product I to iodomethane is 1:1 to 1:

5.

6. The preparation method according to claim 3, characterized in that, (3) The ratio of intermediate product II to ammonia water II is 1:10 to 1:

20.

7. The preparation method according to claim 3, characterized in that, (4) The ratio of the substance with the structure shown in Formula I to the N,N-dimethylacetamide is 1:90 to 1:100; The diameter of the spin coating is 12-15 mm; The volume of the spin coating solution used for spin coating is 20–25 μL.

8. The preparation method according to claim 3, characterized in that, The separation is centrifugal separation.

9. The preparation method according to claim 3, characterized in that, The washing solution used for washing is selected from at least one of water, methanol, ethanol, and acetone.

10. The preparation method according to claim 3, characterized in that, (1) The process of mixing the raw materials containing o-toluidine, dimethoxymethane and trifluoroacetic acid is carried out in an ice-water bath.

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