Alkaline battery negative electrode material and preparation method and application thereof

Abstract

The invention belongs to the technical field of alkaline zinc-manganese batteries, and particularly relates to an alkaline battery negative electrode material as well as a preparation method and application thereof. The negative electrode material is prepared from the following raw materials in percentage by mass: 60 to 68 weight percent of modified zinc powder, 0.7 to 1.5 weight percent of composite binder, 0.3 to 0.5 weight percent of corrosion inhibitor and the balance of electrolyte; the modified zinc powder is prepared through the following preparation processes that zinc powder and polyethylene glycol are added into ethyl alcohol to be evenly dispersed, then cobalt chloride is added, a stirring reaction is conducted, and cobalt-coated zinc powder is obtained; the cobalt-coated zinc powder is added into ethyl alcohol to be evenly dispersed, then gadolinium chloride, sodium tellurite and hydrazine hydrate are added for a reaction, and the modified zinc powder is obtained. The gadolinium-doped cobalt telluride is adopted to perform coating modification on the zinc powder, amino and sulfydryl are adopted to modify the water glass, and the water glass is compounded with the polyacrylic acid to serve as the binder of the negative electrode material, so that the capacity of the alkaline zinc-manganese battery can be improved, and the cycle stability of the battery is improved.

Description

Technical Field

[0001] This invention belongs to the field of alkaline zinc-manganese battery technology, specifically relating to an alkaline battery negative electrode material, its preparation method, and its application. Background Technology

[0002] Alkaline zinc-manganese batteries have a capacity 4-5 times higher than ordinary carbon zinc-manganese batteries, an energy density more than 30% higher than traditional acid zinc-manganese batteries, and better low-temperature discharge performance. They are suitable for various low- and medium-power electronic devices and are therefore widely in demand in various high-power small electronic products.

[0003] In a strongly alkaline electrolyte environment, the zinc anode of a secondary zinc-manganese battery faces a series of severe challenges during repeated charge-discharge cycles, significantly limiting battery life. First, zinc exhibits a strong thermodynamic imbalance during deposition / dissolution, easily leading to uneven zinc deposition and dendrite formation. Dendrite growth not only punctures the separator, causing short circuits, but its breakage and detachment also result in irreversible loss of active material. Second, the zinc anode is chemically reactive in alkaline electrolytes, easily undergoing corrosion side reactions accompanied by hydrogen evolution. This not only consumes electrolyte and active material but also introduces safety hazards such as battery swelling. More critically, the discharge product zinc hydroxide has a certain solubility in the electrolyte, triggering interfacial dissolution and redeposition of active zinc, leading to deterioration of electrode morphology, reduction of actual surface area, and uneven current distribution, further exacerbating performance degradation. Simultaneously, on the positive electrode, manganese dioxide may undergo an irreversible phase transition during deep discharge, generating soluble manganate or causing structural collapse, resulting in loss of active material and degradation of the electrode conductive network. In addition, the consumption and composition changes of the electrolyte during long-term cycling also limit the overall lifespan of the battery.

[0004] Although existing studies have attempted to improve the cycle performance of alkaline zinc-manganese batteries through electrolyte additives, electrode material modification, or separator optimization, these methods often sacrifice initial battery capacity while enhancing cycle stability, making it difficult to achieve a synergistic improvement in both high capacity and long cycle life. Therefore, developing an alkaline zinc-manganese battery that combines high capacity and long cycle life has become an urgent technical problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide an alkaline battery negative electrode material, its preparation method, and its application.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of this invention provides an alkaline battery negative electrode material, the negative electrode material being composed of the following raw materials in mass percentage: 60-68 wt% modified zinc powder, 0.7-1.5 wt% composite binder, 0.3-0.5 wt% corrosion inhibitor, with the balance being electrolyte; The modified zinc powder is prepared by the following process: (1) Add zinc powder and polyethylene glycol to ethanol and disperse evenly, then add cobalt chloride and stir to react. After filtration, washing and drying, cobalt-coated zinc powder is obtained. (2) Cobalt-coated zinc powder was added to ethanol and dispersed evenly. Then, gadolinium chloride, sodium tellurite and hydrazine hydrate were added to react. After filtration, washing and drying, modified zinc powder was obtained.

[0007] Further, in step (1), the ratio of zinc powder, cobalt chloride, polyethylene glycol and ethanol is 1 mol: (0.1-0.2) mol: (3-6) g: (50-200) mL; the stirring reaction time is 5-15 min.

[0008] Further, in step (2), the ratio of cobalt-coated zinc powder, gadolinium chloride, sodium tellurite, hydrazine hydrate and ethanol is 100 g: (0.03-0.08) mol: (0.35-0.6) mol: (4-8) mL: (100-250) mL.

[0009] Furthermore, the heating reaction in step (2) is carried out at a temperature of 170-190 °C for 3-5 h.

[0010] Furthermore, the composite adhesive is prepared by the following method: (a) Sodium silicate is added to water, followed by aminosilane and mercaptosilane, and the mixture is stirred to react and obtain composite modified water glass; (b) The composite modified water glass and polyacrylic acid are mixed evenly to obtain a composite adhesive.

[0011] Further, in step (a), the mass ratio of sodium silicate, aminosilane, mercaptosilane and water is 1:(0.04-0.06):(0.05-0.07):(1.5-1.8); and the stirring reaction time is 0.5-1.5 h.

[0012] Further, the mass ratio of the composite modified water glass to polyacrylic acid in step (b) is 1:(1-1.5).

[0013] Furthermore, the corrosion inhibitor is at least one of ethylenediamine, dodecyl dimethyl betaine, oleamide, and stearamide; the electrolyte is a sodium hydroxide aqueous solution with a mass concentration of 30-36%.

[0014] The second aspect of the present invention provides a method for preparing the above-mentioned alkaline battery negative electrode material, comprising the following steps: mixing modified zinc powder with a composite binder, then adding a corrosion inhibitor and an electrolyte and stirring evenly, and obtaining the alkaline battery negative electrode material after vacuuming.

[0015] A third aspect of the present invention provides an application of the above-mentioned alkaline battery negative electrode material in an alkaline zinc-manganese battery.

[0016] The beneficial technical effects of this invention are as follows: 1. This invention employs gadolinium-doped cobalt telluride to coat and modify zinc powder, which can improve the energy density and cycle stability of alkaline zinc-manganese batteries. Cobalt telluride has good conductivity; coating the zinc powder surface can inhibit zinc powder agglomeration, optimize electron conduction paths, increase the effective specific surface area of ​​active materials, and improve battery capacity. Gadolinium doping can improve the electrolyte wettability of zinc powder and adsorb impurities in the electrolyte, purifying the electrode interface and further improving battery capacity. Moreover, cobalt telluride coating on the zinc powder surface can reduce zinc dissolution in the electrolyte, inhibit zinc dendrite growth, and improve battery cycle stability.

[0017] 2. This invention uses amino- and mercapto-modified water glass, combined with polyacrylic acid, as a binder for the negative electrode material. This binder can form an organic-inorganic cross-linked network, improving the cycle stability of the battery. Sodium silicate aqueous solution is an inorganic binder with high strength and alkali resistance. After modification, the amino groups can cross-link with polyacrylic acid to form an organic-inorganic interpenetrating network, solving problems such as insufficient bonding ability, poor mechanical properties, and poor alkali resistance leading to easy dissolution in organic binders, thus improving the cycle stability of the battery. Mercapto groups have a strong affinity for cobalt and zinc, preferentially adsorbing onto the surface of modified zinc powder, inhibiting zinc dendrite growth and improving the cycle stability of the battery. Furthermore, the adsorption of amino and mercapto groups on the zinc powder surface can form corrosion inhibition sites, inhibiting zinc powder corrosion and improving zinc powder dispersibility, replacing dispersants and some corrosion inhibitors, and reducing the application of additives in the material. Attached Figure Description

[0018] Figure 1 This is a scanning electron microscope image of the modified zinc powder prepared in Example 1 of the present invention; Figure 2 This is a scanning electron microscope image of the composite adhesive prepared in Example 1 of the present invention. Detailed Implementation

[0019] The following is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention. Specific conditions not specified in the embodiments are performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, all reagents or instruments used are conventional products obtained through commercial channels.

[0020] (I) Implementation Examples Example 1 Example 1 provides an alkaline battery negative electrode material, which is composed of the following raw materials in the following mass percentages: 65 wt% modified zinc powder, 1.1 wt% composite binder, 0.4 wt% ethylenediamine, and the balance being a 35% potassium hydroxide electrolyte.

[0021] The modified zinc powder is prepared by the following process: (1) According to the ratio of zinc powder, cobalt chloride, polyethylene glycol 800 and ethanol, 1 mol: 0.1 mol: 5 g: 120 mL, zinc powder and polyethylene glycol 800 were first added to ethanol and ultrasonically dispersed evenly. Then cobalt chloride was added and stirred for 10 min. After filtration, washing and drying, cobalt-coated zinc powder was obtained. (2) According to the ratio of cobalt-coated zinc powder, gadolinium chloride, sodium tellurite, hydrazine hydrate, and ethanol (100 g: 0.05 mol: 0.5 mol: 6 mL: 180 mL), the cobalt-coated zinc powder was added to ethanol and ultrasonically dispersed. Then, gadolinium chloride, sodium tellurite, and hydrazine hydrate were added and mixed evenly. The mixture was reacted at 180 °C for 4 h. After cooling, filtration, washing, and drying, modified zinc powder was obtained. The scanning electron microscope image of the modified zinc powder is shown below. Figure 1 As shown.

[0022] The composite adhesive is prepared by the following method: (a) Sodium silicate was added to water and stirred to dissolve it according to the ratio of sodium silicate, aminosilane, mercaptosilane and water of 10 g: 0.5 g: 0.6 g: 16 mL. Then aminosilane and mercaptosilane were added and stirred for 1.1 h to obtain composite modified water glass. (b) The composite modified water glass and polyacrylic acid (number average molecular weight of 100,000) were mixed evenly at a mass ratio of 1:1.2 to obtain a composite binder. The scanning electron microscope (SEM) results of the composite binder are shown below. Figure 2 As shown.

[0023] This embodiment also provides a method for preparing the above-mentioned alkaline battery negative electrode material, the specific steps of which are as follows: Weigh the above raw materials, first mix the modified zinc powder and composite binder evenly, then add ethylenediamine and electrolyte in proportion, stir evenly and vacuum, to obtain the alkaline battery negative electrode material.

[0024] Example 2 Example 2 provides an alkaline battery negative electrode material, which is composed of the following raw materials in the following mass percentages: 60 wt% modified zinc powder, 0.7 wt% composite binder, 0.3 wt% oleamide, and the balance being a potassium hydroxide electrolyte with a mass concentration of 35%.

[0025] The modified zinc powder is prepared by the following process: (1) According to the ratio of zinc powder, cobalt chloride, polyethylene glycol 800 and ethanol, 1 mol: 0.1 mol: 3 g: 50 mL, zinc powder and polyethylene glycol 800 were first added to ethanol and ultrasonically dispersed evenly. Then cobalt chloride was added and stirred for 5 min. After filtration, washing and drying, cobalt-coated zinc powder was obtained. (2) According to the ratio of cobalt-coated zinc powder, gadolinium chloride, sodium tellurite, hydrazine hydrate and ethanol, 100 g: 0.03 mol: 0.35 mol: 4 mL: 100 mL, cobalt-coated zinc powder was added to ethanol and ultrasonically dispersed. Then, gadolinium chloride, sodium tellurite and hydrazine hydrate were added and mixed evenly. The mixture was reacted at 170 °C for 3 h. After cooling, filtration, washing and drying, modified zinc powder was obtained.

[0026] The composite adhesive is prepared by the following method: (a) Sodium silicate was added to water and stirred to dissolve it according to the ratio of sodium silicate, aminosilane, mercaptosilane and water of 10 g: 0.4 g: 0.5 g: 15 mL. Then aminosilane and mercaptosilane were added and stirred to react for 0.5 h to obtain composite modified water glass. (b) The composite modified water glass and polyacrylic acid (number average molecular weight of 100,000) are mixed evenly according to the mass ratio of 1:1 to obtain the composite adhesive.

[0027] This embodiment also provides a method for preparing the above-mentioned alkaline battery negative electrode material, the specific steps of which are as follows: Weigh the above raw materials, first mix the modified zinc powder and composite binder evenly, then add oleic amide and electrolyte in proportion, stir evenly and vacuum, to obtain alkaline battery negative electrode material.

[0028] Example 3 Example 3 provides an alkaline battery negative electrode material, which is composed of the following raw materials in the following mass percentages: 68 wt% modified zinc powder, 1.5 wt% composite binder, 0.5 wt% stearamide, and the balance being a potassium hydroxide electrolyte with a mass concentration of 35%.

[0029] The modified zinc powder is prepared by the following process: (1) According to the ratio of zinc powder, cobalt chloride, polyethylene glycol 800 and ethanol, 1 mol: 0.2 mol: 6 g: 200 mL, zinc powder and polyethylene glycol 800 were first added to ethanol and ultrasonically dispersed evenly. Then cobalt chloride was added and stirred for 15 min. After filtration, washing and drying, cobalt-coated zinc powder was obtained. (2) According to the ratio of cobalt-coated zinc powder, gadolinium chloride, sodium tellurite, hydrazine hydrate and ethanol, 100 g: 0.08 mol: 0.6 mol: 8 mL: 250 mL, cobalt-coated zinc powder was added to ethanol and ultrasonically dispersed. Then, gadolinium chloride, sodium tellurite and hydrazine hydrate were added and mixed evenly. The mixture was reacted at 190 °C for 5 h. After cooling, filtration, washing and drying, modified zinc powder was obtained.

[0030] The composite adhesive is prepared by the following method: (a) Sodium silicate was added to water and stirred to dissolve it according to the ratio of sodium silicate, aminosilane, mercaptosilane and water of 10 g: 0.6 g: 0.7 g: 18 mL. Then aminosilane and mercaptosilane were added and stirred to react for 1.5 h to obtain composite modified water glass. (b) The composite modified water glass and polyacrylic acid (number average molecular weight of 100,000) were mixed evenly at a mass ratio of 1:1.5 to obtain the composite adhesive.

[0031] This embodiment also provides a method for preparing the above-mentioned alkaline battery negative electrode material, the specific steps of which are as follows: Weigh the above raw materials, first mix the modified zinc powder and composite binder evenly, then add stearamide and electrolyte in proportion, stir evenly and vacuum to obtain alkaline battery negative electrode material.

[0032] (ii) Comparative Example Comparative Example 1 Comparative Example 1 is basically the same as Example 1, except that the modified zinc powder in Example 1 is replaced with zinc powder.

[0033] Comparative Example 2 Comparative Example 2 is basically the same as Example 1, except that gadolinium chloride in step (2) of Example 1 is omitted.

[0034] Comparative Example 3 Comparative Example 3 is basically the same as Example 1, except that the composite adhesive in Example 1 is replaced with polyacrylic acid adhesive.

[0035] Comparative Example 4 Comparative Example 4 is basically the same as Example 1, except that the aminosilane and mercaptosilane in step (a) of Example 1 are omitted.

[0036] (III) Test Examples Using the negative electrode materials prepared in Examples 1-3 and Comparative Examples 1-4 as negative electrodes, electrolytic manganese dioxide, graphite, potassium hydroxide electrolyte with a mass concentration of 35% and polyacrylic acid were mixed evenly at a mass ratio of 90:5:3.5:0.6, pressed into sheets, granulated to obtain a positive electrode ring, and assembled with the shell, positive electrode ring, electrolyte and negative electrode to obtain an alkaline zinc-manganese battery, and the following performance tests were performed.

[0037] Capacity test: The alkaline zinc-manganese batteries prepared in Examples 1-3 and Comparative Examples 1-4 were charged and discharged in the voltage range of 0.8-2.2V and the current density of 0.1C. The capacity of the zinc-manganese batteries in the first test was recorded. The results are shown in Table 1.

[0038] Cyclic testing: The alkaline zinc-manganese batteries prepared in Examples 1-3 and Comparative Examples 1-4 were charged and discharged in the voltage range of 0.8-2.2V and the current density of 0.1C. The capacity retention rate was recorded when the batteries were cycled for 100 cycles. The results are shown in Table 1.

[0039] Continuous discharge test: The alkaline zinc-manganese batteries prepared in Examples 1-3 and Comparative Examples 1-4 were continuously discharged using a 3.9 Ω load until the preset cutoff voltage of 0.8V was reached. The discharge time was recorded, and the results are shown in Table 1.

[0040] Table 1. Capacity, cycle life, and continuous discharge test results of alkaline zinc-manganese batteries As shown in Table 1, the negative electrode materials of Examples 1-3 of the present invention can improve the capacity and cycle stability of alkaline zinc-manganese batteries.

[0041] Compared to Example 1, Comparative Example 1 replaced the modified zinc powder with zinc powder, and Comparative Example 2 omitted gadolinium chloride. The initial battery capacity of both Comparative Examples 1 and 2 showed a significant decrease, and the capacity retention rate after 100 cycles and the continuous discharge time were also affected. This indicates that the use of gadolinium-doped cobalt telluride-modified zinc powder in the negative electrode material of this invention can improve battery capacity and increase battery cycle stability. Specifically, cobalt telluride has good conductivity; coating the zinc powder surface can inhibit zinc powder agglomeration, optimize electron conduction paths, increase the effective specific surface area of ​​the active material, and improve battery capacity. Gadolinium doping can improve the electrolyte wettability of zinc powder and adsorb impurities in the electrolyte, purifying the electrode interface and further improving battery capacity. Furthermore, cobalt telluride coating on the zinc powder surface can reduce zinc dissolution in the electrolyte, inhibit zinc dendrite growth, and improve battery cycle stability.

[0042] Compared to Example 1, Comparative Example 3 replaced the composite binder with a polyacrylic acid binder, and Comparative Example 4 omitted the modification process of water glass with aminosilane and mercaptosilane. Both Comparative Examples 3 and 4 showed a significant decrease in capacity retention and continuous discharge time after 100 cycles. This indicates that the present invention uses amino and mercapto-modified water glass combined with polyacrylic acid as a binder, which can improve the cycle stability of the battery. Specifically, sodium silicate aqueous solution is an inorganic binder with high strength and alkali resistance. After modification, the amino groups can crosslink with polyacrylic acid to form an organic-inorganic interpenetrating network, solving the problems of insufficient bonding ability, poor mechanical properties, and poor alkali resistance and easy dissolution of organic binders, thus improving the cycle stability of the battery. Mercapto groups have a strong affinity for cobalt and zinc, and can preferentially adsorb on the surface of modified zinc powder, inhibiting zinc dendrite growth and improving the cycle stability of the battery.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. The basic principles and main features of the present invention have been described above with specific implementation schemes. Based on the present invention, some modifications or substitutions can be made, but these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of protection claimed by the present invention.

Claims

1. An alkaline battery negative electrode material, characterized in that, The negative electrode material is composed of the following raw materials in the indicated mass percentages: 60-68 wt% modified zinc powder, 0.7-1.5 wt% composite binder, 0.3-0.5 wt% corrosion inhibitor, with the balance being electrolyte; The modified zinc powder is prepared by the following process: (1) Add zinc powder and polyethylene glycol to ethanol and disperse evenly, then add cobalt chloride and stir to react. After filtration, washing and drying, cobalt-coated zinc powder is obtained. (2) Cobalt-coated zinc powder was added to ethanol and dispersed evenly. Then, gadolinium chloride, sodium tellurite and hydrazine hydrate were added to react. After filtration, washing and drying, modified zinc powder was obtained.

2. The alkaline battery negative electrode material according to claim 1, characterized in that, The ratio of zinc powder, cobalt chloride, polyethylene glycol and ethanol used in step (1) is 1 mol: (0.1-0.2) mol: (3-6) g: (50-200) mL; the stirring reaction time is 5-15 min.

3. The alkaline battery negative electrode material according to claim 1, characterized in that, The ratio of cobalt-coated zinc powder, gadolinium chloride, sodium tellurite, hydrazine hydrate and ethanol used in step (2) is 100 g: (0.03-0.08) mol: (0.35-0.6) mol: (4-8) mL: (100-250) mL.

4. The alkaline battery negative electrode material according to claim 1, characterized in that, The reaction in step (2) is carried out at a temperature of 170-190 °C for 3-5 h.

5. The alkaline battery negative electrode material according to claim 1, characterized in that, The composite adhesive is prepared by the following method: (a) Sodium silicate is added to water, followed by aminosilane and mercaptosilane, and the mixture is stirred to react and obtain composite modified water glass; (b) The composite modified water glass and polyacrylic acid are mixed evenly to obtain a composite adhesive.

6. The alkaline battery negative electrode material according to claim 5, characterized in that, The mass ratio of sodium silicate, aminosilane, mercaptosilane and water in step (a) is 1:(0.04-0.06):(0.05-0.07):(1.5-1.8); the stirring reaction time is 0.5-1.5 h.

7. The alkaline battery negative electrode material according to claim 5, characterized in that, The mass ratio of the composite modified water glass to polyacrylic acid in step (b) is 1:(1-1.5).

8. The alkaline battery negative electrode material according to claim 1, characterized in that, The corrosion inhibitor is at least one of ethylenediamine, dodecyl dimethyl betaine, oleamide, and stearamide; the electrolyte is a sodium hydroxide aqueous solution with a mass concentration of 30-36%.

9. A method for preparing the alkaline battery negative electrode material according to any one of claims 1-8, characterized in that, Includes the following steps: The modified zinc powder was mixed with the composite binder, and then the corrosion inhibitor and electrolyte were added and stirred evenly. After vacuuming, the alkaline battery negative electrode material was obtained.

10. The application of the alkaline battery negative electrode material according to claim 1 in an alkaline zinc-manganese battery.

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