A method for preparing a high capacity alkaline zinc-manganese battery

Abstract

This invention discloses a method for preparing a high-capacity alkaline zinc-manganese battery, comprising the preparation of a positive electrode material and an electrolyte. The positive electrode material is made from the following raw materials in parts by weight: 78-87 parts electrolytic manganese dioxide; 3-12 parts fluorinated carbon; 3-7 parts conductive carbon; 2-4 parts binder; and 1-3 parts release agent. The electrolyte is made from the following raw materials in parts by weight: 30-40 parts potassium hydroxide; 55-67 parts deionized water; and 3-5 parts complexing additive. The purity of the potassium hydroxide is ≥95%. The complexing additive is aluminum sulfate and / or potassium aluminum sulfate. This invention, by adding fluorinated carbon to the positive electrode, breaks through the capacity limit of traditional manganese dioxide positive electrodes. Compared with the prior art using only manganese dioxide, it significantly improves the capacity of alkaline zinc-manganese batteries, resulting in products with higher energy density and longer discharge time.

Description

Technical Field

[0001] The present invention relates to a battery processing technology, in particular to a preparation method of a high-capacity alkaline zinc-manganese battery. Background Art

[0002] With the development of technology and the improvement of people's living standards, people's requirements for the energy density of batteries are constantly increasing. As a chemical power source widely used in portable electronic devices, toys, lighting and other fields, alkaline zinc-manganese batteries have the advantages of low cost, high safety, environmental friendliness, etc. However, for the positive active material manganese dioxide in traditional alkaline zinc-manganese batteries, its theoretical specific capacity is only 308 mAh / g, which is difficult to meet the growing demand for high energy density.

[0003] Carbon fluoride (chemical formula: CF X , where 0.5 < x < 1.2) as a new material, its theoretical specific capacity can reach up to 1428 mAh / g, which is much higher than that of manganese dioxide. If carbon fluoride and manganese dioxide can be combined as the positive active material of alkaline batteries, the capacity upper limit of the positive electrode may be broken through, and the energy density of alkaline zinc-manganese batteries can be significantly improved. However, the inventor found in the research that carbon fluoride is unstable in the alkaline system and is easily decomposed into fluoride ions and migrates to the negative electrode, resulting in gas evolution of zinc powder at the negative electrode and a risk of battery leakage. Therefore, how to solve the leakage problem of alkaline zinc-manganese batteries caused by the introduction of carbon fluoride has become the key point and difficulty in the research and development of this direction. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method of a high-capacity alkaline zinc-manganese battery.

[0005] The technical solution to achieve the purpose of the present invention is: a preparation method of a high-capacity alkaline zinc-manganese battery, which includes the preparation of the positive electrode material and the preparation of the electrolyte; wherein, the positive electrode material is prepared from raw materials with the following weight ratios, and each component is in parts by weight: Electrolytic manganese dioxide 78 - 87 parts; Carbon fluoride 3 - 12 parts; Conductive carbon 3 - 7 parts; Binder 2 - 4 parts; Release agent 1 - 3 parts; The conductive carbon is any one or a combination of flake graphite, semi-expanded graphite, and expanded graphite; The binder is any one or a combination of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and ethylene-vinyl acetate copolymer (EVA); The release agent can be any one or a combination of calcium stearate, lithium stearate, and zinc stearate; The electrolyte is prepared from raw materials in the following weight ratio, with each component expressed in parts by weight: 30-40 parts potassium hydroxide; 55-67 parts deionized water; 3-5 parts of complex additive; The purity of the potassium hydroxide is ≥95%; The complex additive is aluminum sulfate and / or potassium aluminum sulfate; The electrolyte is prepared as follows: 1) Add half of the potassium hydroxide to deionized water and stir until completely dissolved to obtain a potassium hydroxide solution; 2) Using the residual heat from the dissolution of potassium hydroxide, add the complexing additive to the potassium hydroxide solution and stir until the complexing additive is completely dissolved. Cool to room temperature to obtain a mixture. 3) Add the remaining potassium hydroxide to the mixture obtained in step 2), stir well, and cool to room temperature.

[0006] Furthermore, the preparation of the positive electrode material includes the mixing of the raw materials for the positive electrode material, which includes the following steps: (1) Premixing: Half of the electrolytic manganese dioxide and all of the fluorinated carbon are stirred through a mixing device at a speed of 600-1000 rpm for 30-50 min to obtain a uniform dark gray mixed powder. (2) Mixing of all components: Add conductive agent, binder, release agent and remaining electrolytic manganese dioxide to the dark gray mixed powder obtained in step 1), continue stirring at 400-800 rpm for 30-50 min to obtain a homogeneous mixture.

[0007] Fluorinated carbon has an average particle size of only 3-10 μm, while electrolytic manganese dioxide has a particle size of 10-60 μm. This significant difference in particle size makes it easy for traditional stirring to result in stratification, with small particles agglomerating and large particles settling. Furthermore, fluorinated carbon has low surface activity and weak interfacial affinity with manganese dioxide, easily forming independent phase regions and making micron-level uniform dispersion impossible. If only conventional stirring (such as uniaxial stirring) is used, even with extended stirring time, it is difficult to break up the initial agglomerates of fluorinated carbon, leading to excessively high or low local concentrations of fluorinated carbon in the cathode material. Excessively high local concentrations increase battery internal resistance and affect discharge stability, while excessively low local concentrations prevent the cathode material from achieving its high specific capacity characteristics. This invention employs a segmented stirring method of pre-mixing followed by full-component mixing, ensuring uniform dispersion of fluorinated carbon.

[0008] Furthermore, the mixing equipment is a dual planetary mixer.

[0009] In existing technologies, while fluorinated carbon is known to have a high specific capacity (1428 mAh / g), its main applications are concentrated in "pure fluorinated carbon-zinc batteries" or other special battery fields, rather than alkaline zinc-manganese batteries. The traditional positive electrode system of alkaline zinc-manganese batteries uses manganese dioxide as the core, and the industry generally focuses on optimizing the purity or particle size of manganese dioxide to improve performance. No one has attempted to introduce fluorinated carbon into this system. Furthermore, fluorinated carbon is unstable in alkaline systems and easily decomposes into fluoride ions that migrate to the negative electrode, causing zinc powder to release gas at the negative electrode and posing a risk of battery leakage. This invention innovatively proposes adding complex additives, such as aluminum sulfate and / or potassium aluminum sulfate, to the electrolyte. For example, potassium aluminum sulfate dissociates into aluminum ions in the electrolyte, and these aluminum ions combine with fluoride ions migrating to the negative electrode to form a stable [AlF6]. 3- The complex prevents fluoride ions from contacting zinc powder, thus preventing the zinc powder from self-corroding and releasing hydrogen, thereby effectively reducing the risk of battery leakage caused by the addition of fluorinated carbon.

[0010] This invention breaks through the capacity limit of traditional manganese dioxide cathodes by adding carbon fluoride to the positive electrode. Compared with the use of manganese dioxide alone in the prior art, it significantly improves the capacity of alkaline zinc-manganese batteries, and the product has higher energy density and longer discharge time. Detailed Implementation

[0011] The preferred embodiments of the present invention will be described in detail below. Example 1

[0012] Taking the LR6 battery as an example, a method for preparing a high-capacity alkaline zinc-manganese battery includes the preparation of a positive electrode material and the preparation of an electrolyte; wherein the positive electrode material is prepared using raw materials with the following weight ratio, and each component is expressed in parts by weight: 82.5 parts of electrolytic manganese dioxide; 7.5 parts of fluorinated carbon; Conductive carbon (expanded graphite) 5 parts; 3 parts adhesive (EVA); Release agent (calcium stearate) 2 parts; The preparation of the positive electrode material includes mixing the raw materials of the positive electrode material, which includes the following steps: (1) Premixing: Add 41.25 parts of electrolytic manganese dioxide and 7.5 parts of fluorinated carbon to a double planetary mixer, set the speed to 800 rpm, and stir for 40 min to obtain a uniform dark gray mixed powder; (2) Mixing of all components: Add the remaining 41.25 parts of electrolytic manganese dioxide, 5 parts of expanded graphite, 3 parts of EVA binder and 2 parts of calcium stearate to the powder above, adjust the speed to 600 rpm and continue stirring for 50 min to obtain a homogeneous mixture.

[0013] The electrolyte is prepared from raw materials in the following weight ratio, with each component expressed in parts by weight: 35 parts of potassium hydroxide with a purity ≥95%; 60 parts deionized water; Complex additive (aluminum sulfate) 5 parts; The electrolyte is prepared as follows: 1) Mix 17.5 parts of potassium hydroxide into water and stir until completely dissolved to obtain a potassium hydroxide solution; 2) While still hot, add 5 parts aluminum sulfate and stir until the aluminum sulfate is completely dissolved. Cool to room temperature to obtain a mixture. 3) Add the remaining 17.5 parts of potassium hydroxide to the mixture obtained in step 2), stir well, and cool to room temperature.

[0014] Table 1:

[0015] The LR6 alkaline zinc-manganese batteries prepared in Examples 1-5, Comparative Example 1, and Comparative Example 2 were subjected to discharge tests. The test results are shown in Table 2. Table 2

[0016] As shown in Table 2, the LR6 alkaline zinc-manganese batteries obtained in Examples 1-5 of this invention have a discharge cycle of ≥3600 times under the simulated smart door lock discharge mode; and a discharge time of ≥8.5h under the simulated 3.9Ω motor toy discharge mode. The discharge cycle and discharge time are significantly higher than those of Comparative Example 2, which does not add carbon fluoride to the positive electrode. Furthermore, the batteries in Examples 1-5 did not leak after 100 days of testing at 60℃ and 90%RH, while Comparative Example 1, which did not add complex additives during electrolyte preparation, showed a leakage rate of 10%.

[0017] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent process transformations made using the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing a high-capacity alkaline zinc-manganese battery, comprising the preparation of a positive electrode material and the preparation of an electrolyte, characterized in that: The positive electrode material is prepared from raw materials in the following weight ratio, with each component expressed in parts by weight: 78-87 parts of electrolytic manganese dioxide; 3-12 parts of fluorinated carbon; 3-7 parts conductive carbon; 2-4 parts adhesive; 1-3 parts release agent; The conductive carbon is any one or a combination of flake graphite, semi-expanded graphite, and expanded graphite. The adhesive is any one or a combination of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and ethylene-vinyl acetate copolymer (EVA). The release agent may be any one or a combination of calcium stearate, lithium stearate, and zinc stearate. The electrolyte is prepared from raw materials in the following weight ratio, with each component expressed in parts by weight: 30-40 parts potassium hydroxide; 55-67 parts deionized water; 3-5 parts of complex additive; The purity of the potassium hydroxide is ≥95%; the complexing additive is aluminum sulfate and / or potassium aluminum sulfate; The electrolyte is prepared as follows: 1) Add half of the potassium hydroxide to deionized water and stir until completely dissolved to obtain a potassium hydroxide solution; 2) While the potassium hydroxide solution is still hot, add the complexing additive and stir until the complexing additive is completely dissolved. Cool to room temperature to obtain a mixture. 3) Add the remaining potassium hydroxide to the mixture obtained in step 2), stir well, and cool to room temperature.

2. The method for preparing a high-capacity alkaline zinc-manganese battery according to claim 1, characterized in that: The preparation of the positive electrode material includes mixing the raw materials of the positive electrode material, which includes the following steps: (1) Premixing: Half of the electrolytic manganese dioxide and all of the fluorinated carbon are stirred through a mixing device at a speed of 600-1000 rpm for 30-50 min to obtain a uniform dark gray mixed powder. (2) Mixing of all components: Add conductive agent, binder, release agent and remaining electrolytic manganese dioxide to the dark gray mixed powder obtained in step 1), continue stirring at 400-800 rpm for 30-50 min to obtain a homogeneous mixture.

3. The method for preparing a high-capacity alkaline zinc-manganese battery according to claim 2, characterized in that: The mixing equipment is a double planetary mixer.

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