Low-temperature-resistant electrolyte for alkaline batteries and preparation method thereof

Abstract

The application discloses a low-temperature-resistant electrolyte for alkaline batteries and a preparation method thereof, and relates to the technical field of electrolytes. The application comprises the following raw materials in mass fraction: glycerol triacetate 11-13 parts, potassium hydroxide aqueous solution 100-150 parts, fluorine-containing additive 1-5 parts, and organic dispersion 21.3-28 parts; the organic dispersion is prepared from ethylene glycol, tetrabutylammonium trifluoromethanesulfonate, hybrid nanosheet and glycerol triacetate. The hybrid nanosheet prepared from hexagonal boron nitride, cerium ammonium nitrate, urea and polyethylene glycol 400 effectively improves the ion conductivity and cycle stability maintenance rate of the electrolyte at low temperature. The introduction of the components such as glycerol triacetate and fluorine-containing additive in the application further improves the performance maintenance rate of the electrolyte at low temperature, and simultaneously reduces the viscosity of the electrolyte at low temperature. Therefore, the application has a more extensive application prospect.

Description

Technical Field

[0001] This invention relates to the field of electrolyte technology, specifically to a low-temperature resistant electrolyte for alkaline batteries and its preparation method. Background Technology

[0002] Alkaline aqueous batteries are a type of energy storage system that uses an alkaline aqueous solution as the electrolyte and metals or metal oxides as electrode materials. They are characterized by high safety, low cost, and environmental friendliness, and are widely used in large-scale energy storage and portable power supplies. The electrolyte in alkaline aqueous batteries mainly consists of a solvent, electrolyte, and additives. Its narrow operating temperature range hinders its application at low temperatures. Although increasing the electrolyte concentration can lower the freezing point based on colligative properties, high-concentration alkaline electrolytes accelerate the passivation and corrosion of metal electrodes, leading to decreased stability of zinc-based batteries.

[0003] To address these issues, engineers proposed adding antifreeze to aqueous battery systems, which effectively lowers the electrolyte's freezing point. However, in practical applications, the electrolyte still exhibits problems such as a significant decrease in electrochemical performance at low temperatures and a substantial increase in viscosity. Therefore, the low-temperature resistance of existing alkaline aqueous battery electrolytes still needs improvement. Summary of the Invention

[0004] The purpose of this invention is to provide a low-temperature resistant electrolyte for alkaline batteries and its preparation method, thereby solving the following technical problems:

[0005] Existing alkaline aqueous battery electrolytes still suffer from poor performance retention at low temperatures.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A low-temperature resistant electrolyte for alkaline batteries comprises the following raw materials by weight: 11-13 parts of glycerol triacetate, 100-150 parts of potassium hydroxide aqueous solution, 1-5 parts of fluorine-containing additive, and 21.3-28 parts of organic dispersion;

[0008] The organic dispersion was prepared from ethylene glycol, tetrabutylammonium trifluoromethanesulfonate, hybrid nanosheets, and glycerol triacetate.

[0009] Preferably, the organic dispersion is prepared by the following method:

[0010] Add tetrabutylammonium trifluoromethanesulfonate to ethylene glycol and stir at 40°C for 2-3 hours. Then add hybrid nanosheets and ultrasonically disperse for 30-60 minutes. Finally, add glycerol triacetate and stir for 20-30 minutes to obtain an organic dispersion.

[0011] Preferably, the mass ratio of ethylene glycol, tetrabutylammonium trifluoromethanesulfonate, hybrid nanosheets, and glycerol triacetate is 13-17:3.8-4:1.2-1.5:3.3-5.5.

[0012] Preferably, the hybrid nanosheets are prepared by the following method:

[0013] A1: At 0-5℃, concentrated sulfuric acid is added dropwise to concentrated nitric acid at 1-2 mL / min. After mixing, hexagonal boron nitride is added and ultrasonically treated at 55-65℃ for 2-3 hours with a power of 700-800W and a frequency of 35-40kHz. After centrifugation and washing until neutral, plasma treatment is performed. Finally, the mixture is vacuum dried at 55-65℃ for 6-8 hours to obtain pretreated boron nitride.

[0014] A2: Add cerium ammonium nitrate and urea to deionized water at 38-42℃ and stir for 20-30 minutes to obtain a mixed dispersion;

[0015] A3: Add anhydrous ethanol to deionized water, pretreat boron nitride, and sonicate for 30-60 min at a power of 450-500 W and a frequency of 35-40 kHz. Then add polyethylene glycol 400 and stir at 58-62℃ for 30-50 min. Then add the mixed dispersion dropwise at 1-2 g / min and stir and reflux at 78-80℃ for 6-7 h. Finally, centrifuge, wash the precipitate with anhydrous ethanol 3-5 times, and vacuum dry at 75-80℃ for 11-15 h to obtain the boron nitride complex.

[0016] A4: High-temperature crystallization treatment of boron nitride composites yields hybrid nanosheets.

[0017] Preferably, the ratio of concentrated sulfuric acid, concentrated nitric acid, and hexagonal boron nitride in A1 is 60-72 mL: 30-36 mL: 7-8.5 g;

[0018] The atmosphere for plasma treatment described in A1 is a combination of hydrogen and nitrogen gases.

[0019] The plasma treatment described in A1 has a power of 280-300W, a pressure of 45-50Pa, an argon gas flow rate of 60-75sccm, an oxygen gas flow rate of 20-25sccm, and a duration of 15-20min.

[0020] Preferably, the mass ratio of deionized water, cerium ammonium nitrate, and urea in A2 is 100-120:5-7:7-10.8.

[0021] Preferably, the ratio of deionized water, anhydrous ethanol, pretreated boron nitride, polyethylene glycol 400, and mixed dispersion in A3 is 50-70 mL: 50-70 mL: 5-7 g: 0.25-0.35 g: 112-137.8 g.

[0022] Preferably, the atmosphere during the high-temperature crystallization treatment described in A4 is a combined hydrogen and nitrogen gas atmosphere;

[0023] The hydrogen gas flow rate during the high-temperature crystallization treatment described in A4 is 5-10 sccm, and the nitrogen gas flow rate is 90-95 sccm.

[0024] The heating procedure for the high-temperature crystallization process described in A4 is as follows: first, heat to 500-550℃ at a rate of 2-5℃ / min, then hold at 500-550℃ for 2-3 hours, and then cool to 20-40℃ at a rate of 1-3℃ / min.

[0025] Preferably, the concentration of the potassium hydroxide aqueous solution is 2-4 mol / L;

[0026] The fluorinated additive is any one of perfluorotriethylamine, perfluorotributylamine, and perfluorotripropylamine.

[0027] A method for preparing a low-temperature resistant electrolyte for alkaline batteries includes the following steps:

[0028] Add glycerol triacetate and fluorine-containing additives to an aqueous potassium hydroxide solution and stir for 10-30 min. Then, add the organic dispersion dropwise at 1-3 g / min and stir for 30-60 min. Finally, degas at -0.1 MPa for 30-60 min to obtain a low-temperature resistant electrolyte for alkaline batteries.

[0029] The beneficial effects of this invention are:

[0030] This invention provides a low-temperature resistant electrolyte for alkaline batteries and its preparation method. The invention effectively improves the performance maintenance capability of the electrolyte for alkaline batteries at low temperatures through the following method.

[0031] (1) During the preparation of the hybrid nanosheets of this invention, the concentrated sulfuric acid-concentrated nitric acid treatment and plasma treatment introduce a large number of polar functional groups such as hydroxyl and carboxyl groups on the surface of hexagonal boron nitride, enhancing its compatibility with polar solvents and avoiding the increase in electrolyte viscosity caused by its agglomeration. The high thermal conductivity of hexagonal boron nitride can accelerate the heat transfer inside the electrolyte at low temperature, reduce local concentration polarization, and maintain ion transport stability. The cerium-based nanoparticles generated by the reaction of cerium ammonium nitrate and urea will be uniformly loaded on the surface of the boron nitride sheet, forming abundant oxygen vacancies and cerium pairs on its surface, which can catalyze the dissociation of water molecules in the electrolyte, promote the solvation and uncoating process of potassium ions, and reduce the activation energy of ion migration at low temperature; it will also form coordination with hydroxide ions in potassium hydroxide electrolyte, stabilize the transport path of potassium ions, and reduce the blockage of ion channels by solvent molecule crystallization at low temperature. After high-temperature crystallization treatment, the defects of the boron nitride sheet can be repaired, and at the same time, the cerium-based compounds may be partially reduced to a low valence state, enhancing their electrostatic interaction with potassium ions and further reducing the resistance to ion migration. The polar functional groups of the hybrid nanosheets can form hydrogen bond networks with ethylene glycol and glycerol triacetate, weakening the van der Waals forces between solvent molecules, making the electrolyte more difficult to crystallize at low temperatures and reducing its supercooling. The "lubricating effect" of the two-dimensional sheets can reduce the frictional resistance between solvent molecules and reduce the viscosity increase of the electrolyte at low temperatures. The oxygen vacancies in cerium-based compounds can serve as "fast transport sites" for potassium ions, forming a conduction pathway similar to an "ion highway". The high specific surface area of ​​the boron nitride sheets after plasma treatment provides an interface for ion adsorption and desorption, shortening the ion diffusion distance and compensating for the weakened thermal motion at low temperatures. After being uniformly dispersed in the electrolyte, the hybrid nanosheets can preferentially adsorb on the electrode surface, forming a composite interfacial film rich in cerium-oxygen bonds and boron nitride sheets. The strong coordination between the cerium-oxygen bonds and potassium ions can reduce the interfacial charge transfer resistance; the chemical inertness of the boron nitride sheets can prevent side reactions between the electrolyte and the electrode, maintaining interfacial stability. The coordination between nanosheets and water can reduce the content of free water molecules, inhibit the growth of ice crystals at low temperatures, and avoid the risk of short circuits caused by ice crystals piercing the electrodes.

[0032] (2) The cations and anions of the tetrabutyltrifluoromethanesulfonate ammonium of the present invention are both large-volume weakly coordinated ions. At low temperatures, the solvation shell is thin and the ion migration resistance is small. Its introduction can supplement the carrier concentration and improve the ionic conductivity. The addition of tetrabutyltrifluoromethanesulfonate ammonium lowers the freezing point of the electrolyte through colligative properties. In synergy with potassium hydroxide, the freezing point can be further lowered, thus delaying the formation of ice crystals.

[0033] (3) Glycerol triacetate can form a eutectic system with solvents such as ethylene glycol, which lowers the freezing point of the electrolyte; its ester group can form an adsorption layer on the surface of zinc electrode, inhibiting the growth of zinc dendrites and improving the structural stability during low-temperature cycling; the addition of glycerol triacetate can reduce the viscosity of the system through dilution effect, reduce the resistance to ion migration, and its weak intermolecular interaction can also help ions to detach from the solvated sheath layer, improve ionic conductivity, and thus improve the charge and discharge efficiency and capacity retention of the battery at low temperature.

[0034] (4) The high stability of perfluorotriethylamine molecules in this invention helps maintain the stability of the electrolyte composition at low temperatures, avoiding a decrease in ion conductivity due to changes in composition. Its fluorinated groups also have low dielectric constants and strong electron-withdrawing capabilities, which can form a weak solvation reaction with cations such as potassium ions, promoting the dissociation of potassium hydroxide in the electrolyte and increasing the concentration of free ions. Its molecular structure can also participate in adjusting the composition of the solvation sheath, reducing the activation energy of ion migration, thereby maintaining a high ion conductivity at low temperatures. The low surface energy characteristics of perfluorotriethylamine can reduce the interfacial tension between the electrolyte and the electrode material, enhance the wetting ability of the electrolyte on the electrode pores, ensure that the electrode active material can fully contact the electrolyte at low temperatures, reduce interfacial resistance, and improve the power density and cycle stability of the battery. Glycerol triacetate maintains the fluidity of the electrolyte by reducing viscosity and freezing point, while perfluorotriethylamine improves the ion migration rate by optimizing ion dissociation and solvation structure. The synergistic effect of the two can significantly improve the ion conductivity of the electrolyte at low temperatures, avoiding a significant decrease in battery capacity. The flexible interfacial film formed by glycerol triacetate, combined with the chemical stability of perfluorotriethylamine, can form a "double protective layer" on the electrode surface. The former reduces interfacial mechanical stress, while the latter inhibits chemical corrosion, thereby reducing the increase in interfacial impedance during low-temperature cycling and improving performance retention.

[0035] Therefore, the low-temperature resistant electrolyte for alkaline batteries prepared by this invention has excellent cycle stability, low-temperature cycle stability and ionic conductivity, as well as a freezing point and viscosity at room temperature and low temperature that are much lower than those of pure potassium hydroxide aqueous solution, and has a wider range of application prospects. Detailed Implementation

[0036] 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, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Unless otherwise specified, the following information pertains to some of the raw materials used in the following embodiments and comparative examples of this invention:

[0038] Polyethylene glycol 400 was purchased from Nanjing Kerunjiang Chemical Co., Ltd., CAS: 25322-68-3.

[0039] Example 1: A method for preparing a low-temperature resistant electrolyte for alkaline batteries is as follows:

[0040] S1: At 0℃, 60mL of concentrated sulfuric acid was added dropwise to 30mL of concentrated nitric acid at a rate of 1mL / min. After mixing, 7g of hexagonal boron nitride was added and the mixture was subjected to ultrasonic treatment at 55℃ for 2h with a power of 700W and a frequency of 35kHz. After centrifugation and washing until neutral, the mixture was subjected to plasma treatment at a power of 280W, a pressure of 45Pa, an argon gas flow rate of 60sccm, and an oxygen gas flow rate of 20sccm for 15min. Finally, the mixture was vacuum dried at 55℃ for 6h to obtain pretreated boron nitride.

[0041] S2: Add 5g of cerium ammonium nitrate and 7g of urea to 100g of deionized water at 38℃ and stir for 20min to obtain a mixed dispersion;

[0042] S3: Add 50 mL of anhydrous ethanol and 5 g of pretreated boron nitride to 50 mL of deionized water and sonicate at 450 W and 35 kHz for 30 min. Then add 0.25 g of polyethylene glycol 400 and stir at 58 °C for 30 min. Then add 112 g of the mixed dispersion dropwise at 1 g / min and stir and reflux at 78 °C for 6 h. Finally, centrifuge, wash the precipitate three times with anhydrous ethanol, and vacuum dry at 75 °C for 11 h to obtain the boron nitride complex.

[0043] S4: The boron nitride composite was placed in a mixed gas atmosphere with a hydrogen gas flow rate of 5 sccm and a nitrogen gas flow rate of 95 sccm, and heated to 500℃ at 2℃ / min. After holding at this temperature for 2 hours, it was cooled to 20℃ at 1℃ / min to obtain hybrid nanosheets.

[0044] S5: Add 3.8g of tetrabutyltrifluoromethanesulfonate to 13g of ethylene glycol and stir at 40℃ for 2h. Then add 1.2g of hybrid nanosheets and perform ultrasonic dispersion at 300W and 35kHz for 30min. Then add 3.3g of glycerol triacetate and stir for 20min to obtain an organic dispersion.

[0045] S6: Add 11 mL of glycerol triacetate and 1 g of perfluorotriethylamine to 100 g of 2 mol / L potassium hydroxide aqueous solution and stir for 10 min. Then add 21.3 g of organic dispersion dropwise at 1 g / min and stir for 30 min. Finally, degas at -0.1 MPa for 30 min to obtain a low-temperature resistant electrolyte for alkaline batteries.

[0046] Example 2: A method for preparing a low-temperature resistant electrolyte for alkaline batteries is as follows:

[0047] S1: At 3℃, 66 mL of concentrated sulfuric acid was added dropwise to 33 mL of concentrated nitric acid at a rate of 1.5 mL / min. After mixing, 7.8 g of hexagonal boron nitride was added and the mixture was subjected to ultrasonic treatment at 60℃ for 2.5 h at a power of 750 W and a frequency of 38 kHz. After centrifugation and washing until neutral, the mixture was subjected to plasma treatment at a power of 290 W, a pressure of 48 Pa, an argon gas flow rate of 67 sccm, and an oxygen gas flow rate of 23 sccm for 18 min. Finally, the mixture was vacuum dried at 60℃ for 7 h to obtain pretreated boron nitride.

[0048] S2: Add 6g of cerium ammonium nitrate and 8.9g of urea to 110g of deionized water at 40℃ and stir for 25min to obtain a mixed dispersion;

[0049] S3: Add 60 mL of anhydrous ethanol and 6 g of pretreated boron nitride to 60 mL of deionized water and sonicate at 480 W and 38 kHz for 45 min. Then add 0.3 g of polyethylene glycol 400 and stir at 60 °C for 40 min. Then add 124.9 g of the mixed dispersion dropwise at 1.5 g / min and stir and reflux at 79 °C for 6.5 h. Finally, centrifuge, wash the precipitate with anhydrous ethanol 4 times, and vacuum dry at 78 °C for 13 h to obtain the boron nitride complex.

[0050] S4: The boron nitride composite was placed in a mixed gas atmosphere of 8 sccm hydrogen gas flow rate and 92 sccm nitrogen gas flow rate, and heated to 530℃ at 4℃ / min. After holding at this temperature for 2.5h, it was cooled to 30℃ at 2℃ / min to obtain hybrid nanosheets.

[0051] S5: Add 3.9g of tetrabutyltrifluoromethanesulfonate to 15g of ethylene glycol and stir at 40℃ for 2.5h. Then add 1.4g of hybrid nanosheets and perform ultrasonic dispersion at 350W and 38kHz for 45min. Then add 4.4g of glycerol triacetate and stir for 25min to obtain an organic dispersion.

[0052] S6: Add 12 mL of glycerol triacetate and 3 g of perfluorotributylamine to 125 g of 3 mol / L potassium hydroxide aqueous solution and stir for 20 min. Then add 24.6 g of organic dispersion dropwise at 2 g / min and stir for 45 min. Finally, degas at -0.1 MPa for 45 min to obtain a low-temperature resistant electrolyte for alkaline batteries.

[0053] Example 3: A method for preparing a low-temperature resistant electrolyte for alkaline batteries is as follows:

[0054] S1: At 5℃, 72mL of concentrated sulfuric acid was added dropwise to 36mL of concentrated nitric acid at a rate of 2mL / min. After mixing, 8.5g of hexagonal boron nitride was added and the mixture was subjected to ultrasonic treatment at 65℃ for 3h with a power of 800W and a frequency of 40kHz. After centrifugation and washing until neutral, the mixture was subjected to plasma treatment at a power of 300W, a pressure of 50Pa, an argon gas flow rate of 75sccm, and an oxygen gas flow rate of 25sccm for 20min. Finally, the mixture was vacuum dried at 65℃ for 8h to obtain pretreated boron nitride.

[0055] S2: Add 7g of cerium ammonium nitrate and 10.8g of urea to 120g of deionized water at 42℃ and stir for 30min to obtain a mixed dispersion;

[0056] S3: Add 70 mL of anhydrous ethanol and 7 g of pretreated boron nitride to 70 mL of deionized water and sonicate at 500 W and 40 kHz for 60 min. Then add 0.35 g of polyethylene glycol 400 and stir at 62 °C for 50 min. Then add 137.8 g of the mixed dispersion dropwise at 2 g / min and stir and reflux at 80 °C for 7 h. Finally, centrifuge, wash the precipitate with anhydrous ethanol 5 times, and vacuum dry at 80 °C for 15 h to obtain the boron nitride complex.

[0057] S4: The boron nitride composite was placed in a mixed gas atmosphere with a hydrogen gas flow rate of 10 sccm and a nitrogen gas flow rate of 90 sccm, and the temperature was increased to 550℃ at 5℃ / min. After holding at the temperature for 3h, it was cooled to 40℃ at 3℃ / min to obtain hybrid nanosheets.

[0058] S5: Add 4g of tetrabutyltrifluoromethanesulfonate to 17g of ethylene glycol and stir at 40℃ for 3h. Then add 1.5g of hybrid nanosheets and perform ultrasonic dispersion at 400W and 40kHz for 60min. Then add 5.5g of glycerol triacetate and stir for 30min to obtain an organic dispersion.

[0059] S6: Add 13 mL of glycerol triacetate and 5 g of perfluorotripropylamine to 150 g of 4 mol / L potassium hydroxide aqueous solution and stir for 30 min. Then, add 28 g of organic dispersion dropwise at 3 g / min and stir for 60 min. Finally, degas at -0.1 MPa for 60 min to obtain a low-temperature resistant electrolyte for alkaline batteries.

[0060] Comparative Example 1:

[0061] Compared with Example 1, this comparative example only replaces the step in the preparation process of S1, which is "at 0°C, 60 mL of concentrated sulfuric acid is added dropwise to 30 mL of concentrated nitric acid at a rate of 1 mL / min, mixed, and then 7 g of hexagonal boron nitride is added and ultrasonic treatment is performed at 55°C for 2 hours with a power of 700 W and a frequency of 35 kHz", with "7 g of hexagonal boron nitride is added to 100 mL of deionized water and ultrasonic treatment is performed at 55°C for 2 hours with a power of 700 W and a frequency of 35 kHz". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a low-temperature resistant electrolyte for alkaline batteries is obtained.

[0062] Comparative Example 2:

[0063] Compared with Example 1, this comparative example only replaces the step "centrifugation and washing to neutrality followed by plasma treatment for 15 min at a power of 280 W, a pressure of 45 Pa, an argon flow rate of 60 sccm, and an oxygen flow rate of 20 sccm, and finally vacuum drying at 55°C for 6 h" in the preparation process of S1 with "centrifugation and washing to neutrality followed by vacuum drying at 55°C for 6 h". All other steps and parameters are the same, and will not be repeated in this comparative example. The final product is a low-temperature resistant electrolyte for alkaline batteries.

[0064] Comparative Example 3:

[0065] Compared with Example 1, this comparative example only replaces the "hybrid nanosheets" added in the preparation process of S5 with the "pretreated boron nitride" prepared in S1. All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a low-temperature resistant electrolyte for alkaline batteries is obtained.

[0066] Comparative Example 4:

[0067] Compared with Example 1, this comparative example only replaces the "hybrid nanosheets" added in the preparation process of S5 with the "boron nitride composite" prepared in S3. All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a low-temperature resistant electrolyte for alkaline batteries is obtained.

[0068] Comparative Example 5:

[0069] Compared with Example 1, this comparative example only omits the addition of "tetrabutyltrifluoromethanesulfonate" during the preparation process of S5. All other steps and parameters are the same, and will not be repeated here. The final product is a low-temperature resistant electrolyte for alkaline batteries.

[0070] Comparative Example 6:

[0071] Compared with Example 1, this comparative example only omits the addition of "glycerol triacetate" in the preparation process of S5. All other steps and parameters are the same, and will not be repeated here. The final product is a low-temperature resistant electrolyte for alkaline batteries.

[0072] Comparative Example 7:

[0073] Compared with Example 1, this comparative example only omits the addition of "glycerol triacetate" in the preparation process of S6. All other steps and parameters are the same, and will not be repeated here. The final product is a low-temperature resistant electrolyte for alkaline batteries.

[0074] Comparative Example 8:

[0075] Compared with Example 1, this comparative example only did not add "perfluorotriethylamine" in the preparation process of S6. All other steps and parameters were the same, and will not be repeated here. The final product is a low-temperature resistant electrolyte for alkaline batteries.

[0076] Performance testing:

[0077] Measurement of ionic conductivity:

[0078] The ionic conductivity (mS·cm) of the alkaline battery electrolytes prepared in Examples 1-3 and Comparative Examples 1-8 at -40°C was measured. -1 The test results are shown in Table 1.

[0079] Determination of cyclic stability:

[0080] The alkaline batteries prepared in Examples 1-3 and Comparative Examples 1-8 of this invention were assembled into rechargeable zinc batteries using low-temperature resistant electrolytes. The batteries were then subjected to 500 cycles at 0.2C, 25℃, and -40℃, respectively. The capacity retention rate (%) after cycling was measured to reflect the cycling stability of the electrolyte. The test results are shown in Table 1.

[0081] Viscosity determination:

[0082] The viscosity (mPa·s) of the alkaline battery low-temperature resistant electrolytes prepared in Examples 1-3 and Comparative Examples 1-8 at 25°C and -40°C was determined, and the test results are shown in Table 1.

[0083] Determination of freezing point:

[0084] The freezing point (°C) of the alkaline battery low-temperature resistant electrolytes prepared in Examples 1-3 and Comparative Examples 1-8 was determined, and the test results are shown in Table 1.

[0085] Table 1: Performance test results of Examples 1-3 and Comparative Examples 1-8

[0086]

[0087] Data Analysis:

[0088] As can be seen from Table 1, the alkaline battery electrolyte prepared in the embodiments of the present invention has excellent cycle stability, low-temperature cycle stability and ionic conductivity, as well as a freezing point and viscosity at room temperature and low temperature that are much lower than those of pure potassium hydroxide aqueous solution.

[0089] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A low-temperature-resistant electrolyte for alkaline batteries, characterized by comprising: The raw materials include the following mass fractions: glycerol triacetate 11-13 parts, potassium hydroxide aqueous solution 100-150 parts, fluorine-containing additive 1-5 parts, and organic dispersion liquid 21.3-28 parts; The organic dispersion liquid is prepared from ethylene glycol, tetrabutylammonium trifluoromethanesulfonate, hybrid nanosheet, and glycerol triacetate; The preparation method of the hybrid nanosheet is as follows: A1: concentrated sulfuric acid is added dropwise into concentrated nitric acid at 0-5 ℃, hexagonal boron nitride is added after mixing, ultrasonic treatment is performed at 55-65 ℃ for 2-3 h, centrifugal washing is performed until neutral, plasma treatment is performed, and finally vacuum drying is performed to obtain pretreated boron nitride; A2: cerium ammonium nitrate and urea are added into deionized water at 38-42 ℃ and stirred for 20-30 min to obtain a mixed dispersion liquid; A3: anhydrous ethanol and pretreated boron nitride are added into deionized water and ultrasonic treatment is performed for 30-60 min, then polyethylene glycol 400 is added and stirred at 58-62 ℃ for 30-50 min, the mixed dispersion liquid is then added dropwise, and stirring reflux is performed at 78-80 ℃ for 6-7 h, finally centrifugal separation, washing and precipitation, and vacuum drying are sequentially performed to obtain a boron nitride composite; A4: high-temperature crystallization treatment is performed on the boron nitride composite to obtain a hybrid nanosheet; The concentration of the potassium hydroxide aqueous solution is 2-4 mol / L; The fluorine-containing additive is any one of perfluorotriethylamine, perfluorotributylamine, and perfluorotripropylamine; The atmosphere during the high-temperature crystallization treatment in A4 is a hydrogen-nitrogen mixed gas atmosphere; The hydrogen gas flow rate during the high-temperature crystallization treatment in A4 is 5-10 sccm, and the nitrogen gas flow rate is 90-95 sccm; The temperature rising program during the high-temperature crystallization treatment in A4 is first rising at 2-5 ℃ / min to 500-550 ℃, then maintaining at 500-550 ℃ for 2-3 h, and then cooling at 1-3 ℃ / min to 20-40 ℃.

2. The low-temperature-resistant electrolyte for alkaline batteries according to claim 1, characterized by The preparation method of the organic dispersion liquid is as follows: Tetrabutylammonium trifluoromethanesulfonate is added into ethylene glycol and stirred at 40 ℃ for 2-3 h, then the hybrid nanosheet is added and ultrasonic dispersed for 30-60 min, and then glycerol triacetate is added and stirred for 20-30 min to obtain the organic dispersion liquid.

3. The low-temperature-resistant electrolyte for alkaline batteries according to claim 2, characterized by The mass ratio of the ethylene glycol, tetrabutylammonium trifluoromethanesulfonate, hybrid nanosheet, and glycerol triacetate is 13-17:3.8-4:1.2-1.5:3.3-5.

5.

4. The low-temperature-resistant electrolyte for alkaline batteries according to claim 1, characterized by The amount ratio of the concentrated sulfuric acid, concentrated nitric acid, and hexagonal boron nitride in A1 is 60-72 mL:30-36 mL:7-8.5 g; The atmosphere during the plasma treatment in A1 is a hydrogen-nitrogen mixed gas atmosphere; The power during the plasma treatment in A1 is 280-300 W, the pressure is 45-50 Pa, the argon gas flow rate is 60-75 sccm, the oxygen gas flow rate is 20-25 sccm, and the time length is 15-20 min.

5. The low-temperature-resistant electrolyte for alkaline batteries according to claim 1, characterized by The mass ratio of the deionized water, cerium ammonium nitrate, and urea in A2 is 100-120:5-7:7-10.

8.

6. The low-temperature-resistant electrolyte for alkaline batteries according to claim 1, characterized by The amount ratio of the deionized water, the anhydrous ethanol, the pretreated boron nitride, the polyethylene glycol 400 and the mixed dispersion liquid in A3 is 50-70 mL: 50-70 mL: 5-7 g: 0.25-0.35 g: 112-137.8 g.

7. A method for producing a low-temperature-resistant electrolyte for alkaline batteries according to any one of claims 1 to 6, characterized by, The method comprises the following steps: The glycerol triacetate and the fluorine-containing additive are added into the potassium hydroxide aqueous solution and stirred for 10-30 min, then the organic dispersion liquid is dropped and stirred for 30-60 min, and finally, the defoaming is carried out under-0.1 MPa for 30-60 min, so as to obtain the low-temperature-resistant electrolyte for alkaline batteries.

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