Preparation method of zinc negative electrode wide temperature type coating material for Ah-grade zinc-manganese dioxide soft package battery

Abstract

The invention discloses a preparation method of a zinc negative electrode wide temperature type coating material for an Ah-grade zinc-manganese dioxide soft package battery. Zinc fluoride and zinc carbonate additives are introduced into a commercial coating to construct a zinc negative electrode organic-inorganic composite coating. At a low temperature (-30 DEG C), inorganic components in the coating promote migration and uniform deposition of Zn, and an organic layer blocks water corrosion and inhibits a hydrogen evolution reaction; at the high temperature (60 DEG C), the coating effectively reduces the content of free water on the zinc surface and inhibits side reaction and dendritic crystal growth caused by high water activity. The ZnMnO total battery assembled by the coating modified zinc foil can stably circulate for 1000 circles under the current density of 1A g at the temperature of-30 DEG C and 60 DEG C. The assembled zinc-manganese dioxide soft package battery can stably circulate for 20 circles at the temperature of-20 DEG C, and the capacity reaches 1.4 Ah. In conclusion, the coating modified zinc negative electrode obviously enhances the wide temperature range stability of the zinc-manganese dioxide soft package battery. The preparation process is simple, efficient and low in cost, and meets the requirements of environmental and economic benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of aqueous zinc-manganese dioxide secondary batteries, and in particular to a preparation method and application of a zinc negative electrode wide-temperature coating capable of realizing Ah-level zinc-manganese dioxide soft-pack batteries. Background Art

[0002] Aqueous zinc metal batteries (AZIBs) are attractive due to their high safety, low cost, and high theoretical capacity (820 mAh g -1 , 5854mAhcm -3 ) and environmentally friendly characteristics, and have great application potential in the field of energy storage. However, the lack of adaptability to a wide temperature range seriously hinders its commercialization: freezing of the electrolyte at low temperatures leads to a sharp drop in ionic conductivity and hysteresis of interface kinetics; at high temperatures, the enhanced proton activity leads to intensified hydrogen evolution corrosion of the zinc negative electrode, and the uneven distribution of zinc ions induces dendrite growth. Among the existing modification strategies, the non-in-situ surface coating technology can simultaneously suppress dendrites and side reactions by pre-constructing a stable interface layer, combining the advantages of process simplicity and electrolyte universality. However, current research is mostly limited to small-capacity simulated batteries (<100mAh), and there is a lack of empirical evidence to verify the wide temperature cycling stability of -30 to 60°C in Ah-level large-capacity batteries. Therefore, the development of a coating strategy suitable for high-load zinc negative electrodes to ensure the long-term cycling of ampere-hour-level AZIBs at extreme temperatures is a key direction that urgently needs to be broken through to promote industrialization.

[0003] The present invention introduces zinc fluoride and zinc carbonate (ZnF2 and ZnCO3) as additives into commercial coatings to construct an organic-inorganic composite coating for zinc negative electrodes. At low temperatures (-30°C), the inorganic components ZnF2 and ZnCO3 in the coating are beneficial to the absorption of Zn 2+ The organic layer can effectively avoid water corrosion and the formation of HER, thereby improving the stability of the Zn negative electrode. Compared with high temperature (60°C), the organic-inorganic protective layer can reduce the content of free water molecules on the zinc surface, thereby effectively inhibiting the more severe side reactions and dendrite problems caused by the increase in electrolyte water activity at high temperature, and ultimately achieving excellent zinc storage performance and Ah-level zinc-manganese dioxide soft-pack battery performance under harsh conditions in a wide temperature range (-30 to 60°C). Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing a wide-temperature zinc negative electrode coating for Ah-level zinc-manganese dioxide soft-pack batteries and its application. By introducing zinc fluoride and zinc carbonate into the commercial coating, the side reactions and hydrogen evolution corrosion caused by active water are effectively inhibited by promoting the migration of zinc ions and reducing the content of active water molecules on the surface of the zinc negative electrode, thereby achieving the stability of the zinc negative electrode under harsh conditions of -30 to 60°C, thereby improving the chemical reversibility of the ampere-hour-level zinc-based soft-pack batteries.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] (1) Weighing a certain mass of zinc fluoride and zinc carbonate and adding them to a certain amount of coating, stirring the coating for several hours to fully mix it, thereby obtaining a coating slurry; finally, coating the coating slurry on zinc foil, and vacuum drying it at a certain temperature to obtain a coated zinc foil;

[0007] (2) Preparation of a composite gel electrolyte: dissolving a soluble zinc salt in a certain amount of a mixed solvent to obtain a uniform solution, and then immersing a polyacrylamide gel in the uniform solution for a certain period of time to obtain a composite gel electrolyte, wherein the mixed solvent is an aqueous solution of N,N-dimethylformamide and water in different volume ratios;

[0008] (3) Battery preparation: using the coated zinc foil prepared in step (1) as the negative electrode, the coated zinc foil or manganese dioxide as the positive electrode, and the composite gel electrolyte prepared in step (2) as the electrolyte, assembling a button-type zinc-manganese dioxide full battery or a zinc-manganese dioxide soft-pack battery, and testing its zinc storage performance.

[0009] The coating in the above step (1) is a polyamide coating produced by Fuqing Keteng Industrial Co., Ltd.; the concentration of zinc fluoride and zinc carbonate is 0.1-10 g / L, and the thickness of the zinc foil is 50-250 μm; the vacuum drying temperature is 40-80° C., and the time is 0.2-6 hours.

[0010] The soluble zinc salt described in the above step (2) is selected from zinc sulfate, zinc trifluoromethanesulfonate, zinc acetate, zinc chloride or zinc perchlorate, and the concentration of the soluble zinc salt is 1 to 10 mol L-1; the volume of the mixed solvent is 10 to 30 mL, and the volume ratio of dimethylformamide to water in the mixed solvent is (4 to 1): (6 to 9); the polyacrylamide gel is purchased from Yanwen Research Co., Ltd.; and the soaking time is 0.1 to 3 hours.

[0011] The manganese dioxide positive electrode in the button-type zinc-manganese dioxide full battery in the above step (3) is prepared by the following method: manganese dioxide, a conductive agent, and a binder are mixed in a mass ratio of 8:1:1, mixed in a certain solvent, and then coated on a carbon cloth, and placed in a vacuum drying oven at 60°C for 10 hours to obtain a manganese dioxide positive electrode sheet, wherein the mass areal loading of the manganese dioxide positive electrode material in the manganese dioxide positive electrode sheet is 1.0 to 10.0 mg cm-2.

[0012] The preparation method of the manganese dioxide positive electrode in the zinc-manganese dioxide soft-pack battery in the above step (3) is as follows: manganese dioxide, acetylene black, and polytetrafluoroethylene in a mass ratio of 8:1:1 are placed in a certain amount of solvent, mixed and stirred for a certain period of time to form a dough, then rolled onto a titanium mesh current collector, and vacuum dried at 60°C for 10 hours to prepare a soft-pack manganese dioxide positive electrode sheet, wherein the mass areal loading of the manganese dioxide positive electrode material in the soft-pack manganese dioxide positive electrode sheet is 20 to 100 mg cm-2.

[0013] The preparation process of the button-type zinc-zinc symmetrical battery in the above step (3) is as follows: the zinc foil prepared in step (1) is used as the negative electrode and the positive electrode, and the gel prepared in step (2) is used as the electrolyte to assemble into a button-type battery (CR2032 type).

[0014] The preparation process of the button-type zinc-manganese dioxide full battery in the above step (3) is as follows: the coated modified zinc foil is used as the negative electrode, the above-mentioned manganese dioxide positive electrode sheet is used as the positive electrode, and the composite gel prepared in step (2) is used as the electrolyte to assemble into a button-type battery (CR2032 type).

[0015] The preparation process of the zinc-manganese dioxide soft-pack battery in the above step (3) is as follows: the size of the aluminum-plastic film of the outer packaging body is 12 cm × 12 cm, the size of a single piece of the coated zinc foil negative electrode is 10 cm × 10 cm, the size of a single piece of the above-mentioned soft-pack manganese dioxide positive electrode sheet is 9 cm × 9 cm, and the size of the dimethyl hydrogel electrolyte is 10 cm × 10 cm. The negative electrode, the composite gel electrolyte, and the positive electrode are stacked and assembled in sequence to obtain a zinc-manganese dioxide soft-pack battery.

[0016] The invention relates to an application of the zinc negative electrode wide-temperature coating material prepared by the above-mentioned preparation method in the manufacture of button batteries or zinc-manganese dioxide soft-pack batteries.

[0017] Compared with the existing technology, the present invention has the following specific advantages:

[0018] (1) Zinc negative electrode coating modification is a promising modification method to improve the performance of zinc-based energy storage devices. It has a simple process and uses cheap raw materials.

[0019] (2) Introducing zinc fluoride and zinc carbonate into commercial coatings can enable zinc-based batteries to operate stably over a wide temperature range.

[0020] (3) The present invention introduces zinc fluoride and zinc carbonate into commercial coatings, which can improve the electrolytic / electrolyte interface and optimize zinc ion transmission and electrode reaction at high and low temperatures, thereby protecting the stability of the zinc negative electrode in high and low temperature environments and ensuring the normal operation of zinc-based energy storage devices under harsh conditions.

[0021] (4) The introduction of zinc fluoride and sodium carbonate into the zinc negative electrode coating is effective and practical. The Zn||MnO2 full battery assembled with zinc negative electrode containing zinc fluoride and zinc carbonate was -1 After 2500 cycles at the same current density, the zinc-manganese soft-pack battery assembled with the zinc negative electrode prepared by the coating can stably cycle 20 cycles at a low temperature of -20°C, and the reversible capacity reaches 1.4Ah; at a low temperature of -30°C, the assembled Zn||MnO2 full battery can reversibly ... -1 The assembled Zn||MnO2 full battery was cycled for 1000 cycles at a current density of 60°C under a high temperature environment at 1Ag -1 It can still cycle stably for 1000 cycles at the same current density. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a SEM image of the zinc negative electrode after the coating-modified zinc negative electrode obtained in Example 1 is assembled into a battery and cycled.

[0023] Figure 2 This is an AFM image of the zinc negative electrode after the coating-modified zinc negative electrode obtained in Example 1 is assembled into a battery and cycled.

[0024] Figure 3 The coating modified zinc negative electrode obtained in Example 1 was assembled into a symmetrical battery at 2 mA cm -2 Cycling performance diagram at current density of .

[0025] Figure 4 The coating modified zinc negative electrode obtained in Example 1 is assembled into a Zn||MnO2 full battery at room temperature, 1Ag -1 Cycling performance diagram at current density of .

[0026] Figure 5 The coating modified zinc negative electrode obtained in Example 1 was assembled into a Zn||MnO2 full battery under harsh conditions of low temperature (-30°C) and high temperature (60°C). -1 Cycling performance diagram at current density of .

[0027] Figure 6 The coating modified zinc negative electrode obtained in Example 1 was assembled into a Zn||MnO2 soft pack battery at a low temperature (-20°C) with a flow rate of 2 mA cm -2 Cycling performance diagram at current density of . DETAILED DESCRIPTION

[0028] Example 1

[0029] A certain amount of zinc fluoride (10 mg) and zinc carbonate (10 mg) were weighed and added to a commercial polyamide coating (20 mL, produced by Fuqing Keteng Industrial Co., Ltd.). The coating was then stirred for several hours to fully mix with the zinc fluoride (10 mg) and zinc carbonate (10 mg) to obtain a coating slurry. The coating slurry was coated on a 250 μm zinc foil using a doctor blade method and vacuum-dried at 60°C for 3 hours to obtain a coated zinc negative electrode (also referred to as coated zinc foil in this invention). 2M zinc sulfate was dissolved in 15 mL of a mixed solvent prepared by mixing N,N-dimethylformamide and water in a volume ratio of 3:7 to form a uniform solution. The polyacrylamide gel was immersed in the above uniform solution for 2 hours to prepare a composite gel electrolyte. The modified coating-modified zinc negative electrode has an organic-inorganic protective layer, which can effectively inhibit the direct contact between the surface active water molecules and the zinc negative electrode, thereby effectively inhibiting the side reactions and hydrogen evolution corrosion caused by water; at the same time, the inorganic layer can promote the ion transport of the coating-modified zinc negative electrode in a relatively cold environment to promote the uniform deposition of zinc. Therefore, the battery assembled with the coating-modified zinc negative electrode after coating modification can work stably for a long time under a wide temperature range (-30 to 60 ° C). From the SEM image after the cycle, it can be seen that the coating modification has achieved a uniform and smooth deposition surface ( Figure 1 ); Similarly, the AFM image after cycling shows that zinc ions are uniformly deposited, the negative electrode is relatively flat, and there are no large protrusions ( Figure 2 The symmetrical battery assembled with the coating-modified zinc anode designed by the coating is at 2 mA cm -2 It can be cycled stably for 2000h at a current density of Figure 3 ), has a long cycle life. In addition, the coated zinc foil (also known as the coated modified zinc negative electrode in the present invention) is used as the negative electrode, the composite gel electrolyte acts as the separator and electrolyte, and the manganese dioxide positive electrode sheet prepared in Example 5 is used as the positive electrode material. The assembled Zn||MnO2 is 1Ag -1 It can cycle 2500 times at a current density of 10000, and the coulombic efficiency is as high as 99.66% ( Figure 4 Even at -30℃ and 60℃, it can still stably cycle 1000 times ( Figure 5 ). Similarly, a Zn||MnO2 soft-pack battery was assembled using the coated zinc foil as the negative electrode. The manganese-based positive electrode material area of ​​the soft-pack manganese dioxide positive electrode sheet prepared in Example 6 was 9 cm×9 cm, and the negative electrode area was 10 cm×10 cm. At 2 mA cm -2 Cycled 20 times at a current density of 1000 nm, with a surface loading of 42 mg cm -2 , the capacity reaches 1.4Ah( Figure 6 ). These results further confirm that the coating modification has certain practical application value.

[0030] Example 2

[0031] A certain amount of zinc fluoride (0.5g) and zinc carbonate (0.5g) were weighed and added to a commercial polyamide coating (1L, produced by Fuqing Keteng Industrial Co., Ltd.). The coating was then stirred for several hours to thoroughly mix with the zinc fluoride and zinc carbonate to form a coating slurry. The slurry was then coated on a 250μm zinc foil using a doctor blade method and vacuum-dried at 40°C for 6 hours to obtain a modified zinc anode. 2M zinc trifluoromethanesulfonate was dissolved in 10mL of a mixed solvent prepared by mixing N,N-dimethylformamide and water in a volume ratio of 2:8 to form a uniform solution. Polyacrylamide gel was immersed in this uniform solution for 2 hours to prepare a composite gel electrolyte. A Zn||Zn symmetrical battery was assembled using the modified zinc foil as the negative electrode and the positive electrode, and the composite gel electrolyte as the separator and the electrolyte; a Zn||MnO2 button full battery was assembled using the modified zinc foil as the negative electrode, the manganese dioxide positive electrode sheet prepared in Example 5 as the positive electrode material, and 2M zinc trifluoromethanesulfonate as the soluble zinc salt in the gel electrolyte; a Zn||MnO2 soft-pack battery was assembled by stacking the negative electrode, the composite gel, and the positive electrode in this order.

[0032] Example 3

[0033] A certain amount of zinc fluoride (5g) and zinc carbonate (5g) were weighed and added to a commercial polyamide coating (10L, produced by Fuqing Keteng Industrial Co., Ltd.). The coating was then stirred for several hours to thoroughly mix with the zinc fluoride and zinc carbonate to form a coating slurry. The slurry was then coated on a 250μm zinc foil using a doctor blade method and vacuum-dried at 60°C for 4 hours to obtain a modified zinc anode. 2M zinc chloride was dissolved in 15mL of a mixed solvent of N,N-dimethylformamide and water in a volume ratio of 3:7 to form a uniform solution. The polyacrylamide gel was immersed in this uniform solution for 2 hours to prepare a composite gel electrolyte. A Zn||Zn symmetrical battery was assembled using modified zinc foil as the negative electrode and positive electrode, and a composite gel electrolyte as the separator and electrolyte; a Zn||MnO2 button full battery was assembled using the modified zinc foil as the negative electrode, the manganese dioxide positive electrode sheet prepared in Example 5 as the positive electrode material, and zinc chloride as the soluble zinc salt in the gel electrolyte; a Zn||MnO2 soft-pack battery was assembled by stacking the negative electrode, composite gel, and positive electrode in sequence using the modified zinc foil as the negative electrode, the soft-pack manganese dioxide positive electrode sheet prepared in Example 6 as the positive electrode material, and 2M zinc chloride as the soluble zinc salt in the gel electrolyte.

[0034] Example 4

[0035] A certain amount of zinc fluoride (100g) and zinc carbonate (100g) were weighed and added to a commercial polyamide coating (200L, produced by Fuqing Keteng Industrial Co., Ltd.). The coating was then stirred for several hours to thoroughly mix with the zinc fluoride and zinc carbonate to form a coating slurry. The slurry was then coated on a 250μm zinc foil using a doctor blade method and vacuum-dried at 80°C for 1 hour to obtain a modified zinc anode. 2M zinc acetate was dissolved in 10mL of a mixed solvent of N,N-dimethylformamide and water in a volume ratio of 1:9 to form a uniform solution. Polyacrylamide gel was immersed in this uniform solution for 1 hour to prepare a composite gel electrolyte. A Zn||Zn symmetrical battery was assembled using the modified zinc foil as the negative electrode and the positive electrode, and the composite gel electrolyte as the separator and the electrolyte; a Zn||MnO2 button full battery was assembled using the modified zinc foil as the negative electrode, the manganese dioxide positive electrode sheet prepared in Example 5 as the positive electrode material, and 2M zinc acetate as the soluble zinc salt in the gel electrolyte; a Zn||MnO2 soft-pack battery was assembled by stacking the negative electrode, the composite gel, and the positive electrode in this order.

[0036] Example 5

[0037] The manganese dioxide positive electrode in the button-type zinc-manganese dioxide full battery is prepared by the following method: manganese dioxide, acetylene black, and polytetrafluoroethylene are mixed in a mass ratio of 40 mg:5 mg:5 mg, mixed in 400 μl of N-methylpyrrolidone solvent, and then coated on carbon cloth. The mixture is placed in a vacuum drying oven at 60° C. and dried for 10 hours to obtain a manganese dioxide positive electrode sheet. The mass areal loading of the manganese dioxide positive electrode material in the manganese dioxide positive electrode sheet is 1.0 to 10.0 mg cm -2 .

[0038] Example 6

[0039] Preparation method of manganese dioxide positive electrode in zinc-manganese dioxide soft-pack battery: manganese dioxide, acetylene black and polytetrafluoroethylene with a mass ratio of 4g:0.5g:0.5g are placed in 40mL of N-methylpyrrolidone solvent, mixed and stirred for 3 hours to form a dough, then rolled onto a titanium mesh current collector, and vacuum dried at 60°C for 10 hours to prepare a soft-pack manganese dioxide positive electrode sheet. The mass areal loading of manganese dioxide positive electrode material in the soft-pack manganese dioxide positive electrode sheet is 20-100mgcm -2 .

[0040] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A method for preparing a zinc negative electrode wide-temperature coating material for Ah-level zinc-manganese dioxide soft-pack batteries, comprising the following steps: (1) Weighing a certain mass of zinc fluoride and zinc carbonate and adding them to a certain amount of coating, stirring the coating for several hours to fully mix it, thereby obtaining a coating slurry; finally, coating the coating slurry on zinc foil, and vacuum drying it at a certain temperature to obtain a coated zinc foil; (2) Preparation of composite gel electrolyte: dissolving a soluble zinc salt in a certain amount of mixed solvent to prepare a uniform solution, and then immersing the polyacrylamide gel in the uniform solution for a certain period of time to prepare a composite gel electrolyte, wherein the mixed solvent is an aqueous solution of N, N-dimethylformamide and water in different volume ratios; (3) Battery preparation: using the coated zinc foil prepared in step (1) as the negative electrode, the coated zinc foil or manganese dioxide as the positive electrode, and the composite gel electrolyte prepared in step (2) as the electrolyte, assemble into a button-type zinc-manganese dioxide full battery or a zinc-manganese dioxide soft-pack battery, and test its zinc storage performance.

2. The method for preparing the zinc negative electrode wide temperature coating material according to claim 1, wherein The coating in step (1) is a polyamide coating produced by Fuqing Keteng Industrial Co., Ltd.; the concentration of zinc fluoride and zinc carbonate is 0.1~10 g / L, and the thickness of the zinc foil is 50~250 μm; the vacuum drying temperature is 40~80 °C, and the time is 0.2~6 hours.

3. The method for preparing the zinc negative electrode wide temperature coating material according to claim 1, wherein: The soluble zinc salt in step (2) is selected from zinc sulfate, zinc trifluoromethanesulfonate, zinc acetate, zinc chloride or zinc perchlorate, and the concentration of the soluble zinc salt is 1-10 mol L -1 The volume of the mixed solvent was 10-30 mL, and the volume ratio of dimethylformamide to water in the mixed solvent was (4-1): (6-9). Polyacrylamide gel was purchased from Yanwen Research Co., Ltd. The soaking time was 0.1-3 hours.

4. The method for preparing the zinc negative electrode wide temperature coating material according to claim 1, wherein The manganese dioxide positive electrode in the button-type zinc-manganese dioxide full battery is prepared by the following method: manganese dioxide, a conductive agent, and a binder are mixed in a mass ratio of 8:1:1, mixed in a certain solvent, and then coated on a carbon cloth. The mixture is placed in a vacuum drying oven at 60°C for 10 hours to obtain a manganese dioxide positive electrode sheet. The mass areal loading of the manganese dioxide positive electrode material in the manganese dioxide positive electrode sheet is 1.0-10.0 mg cm -2 .

5. The method for preparing the zinc negative electrode wide temperature coating material according to claim 1, wherein A method for preparing a manganese dioxide positive electrode in a zinc-manganese dioxide soft-pack battery comprises placing manganese dioxide, acetylene black, and polytetrafluoroethylene in a mass ratio of 8:1:1 in a certain amount of solvent, stirring the mixture for a certain period of time to form a dough, rolling the dough onto a titanium mesh current collector, and vacuum drying the mixture at 60°C for 10 hours to prepare a soft-pack manganese dioxide positive electrode sheet. The mass areal loading of the manganese dioxide positive electrode material in the soft-pack manganese dioxide positive electrode sheet is 20-100 mg cm -2 .

6. The method for preparing the zinc negative electrode wide temperature coating material according to claim 1, characterized in that: The preparation process of a button-type zinc-zinc symmetrical battery is as follows: the zinc foil prepared in step (1) is used as the negative electrode and the positive electrode, and the gel prepared in step (2) is used as the electrolyte to assemble into a button-type battery (CR2032 type).

7. The method for preparing the zinc negative electrode wide temperature coating material according to claim 1, characterized in that: The preparation process of a button-type zinc-manganese dioxide full battery is as follows: a coated modified zinc foil is used as a negative electrode, the manganese dioxide positive electrode sheet described in claim 4 is used as a positive electrode, and the composite gel prepared in step (2) is used as an electrolyte, and they are assembled into a button-type battery (CR2032 type).

8. The method for preparing the zinc negative electrode wide temperature coating material according to claim 1, wherein The preparation process of the zinc-manganese dioxide soft-pack battery is as follows: the size of the aluminum-plastic film of the outer packaging body is 12 cm×12 cm, the size of a single piece of the coated zinc foil negative electrode is 10 cm×10 cm, the size of a single piece of the soft-pack manganese dioxide positive electrode sheet according to claim 5 is 9 cm×9 cm, and the size of the dimethyl hydrogel electrolyte is 10 cm×10 cm. The negative electrode, the composite gel electrolyte, and the positive electrode are stacked and assembled in this order to obtain the zinc-manganese dioxide soft-pack battery.

9. Use of the zinc negative electrode wide-temperature coating material prepared by the preparation method according to any one of claims 1 to 8 in the manufacture of button batteries or zinc-manganese dioxide soft-pack batteries.

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