CN1971978A - Zinc cathode secondary battery, zinc cathode of the battery and preparation method thereof - Google Patents

Abstract

A secondary battery zinc negative electrode, the negative electrode includes a current collector and a negative electrode material coated and/or filled on the current collector, the negative electrode material contains a negative electrode active material and a binder, and the negative electrode active material contains zinc element and/or Zinc oxide, wherein the negative electrode active material also contains a zinc salt insoluble in alkaline electrolyte. The zinc negative electrode secondary battery provided by the invention can effectively suppress the deformation of the zinc electrode without reducing the energy density of the battery. After many cycles, the remaining rate of the zinc negative electrode area is high, and the battery capacity decays slowly.

Description

Zinc negative electrode secondary battery, zinc negative electrode of the battery and their preparation method

technical field

The present invention relates to a battery and its negative electrode and their preparation method, more specifically to a zinc negative electrode secondary battery, the battery's zinc negative electrode and their preparation method.

Background technique

For traditional secondary batteries with zinc as the negative electrode, such as zinc-silver batteries and zinc-nickel batteries, the battery capacity decays rapidly with the increase of the number of cycles. This capacity fading is attributed to the change in the morphology of the zinc electrode, which is called deformation of the zinc electrode by those skilled in the art.

In the secondary battery with zinc element and/or zinc oxide as the negative electrode active material, the zinc on the electrode is transformed into zinc oxide during the discharge process, and transformed into metallic zinc again during the charge process. During the discharge process of the battery, the metal zinc on the zinc electrode is oxidized to form zinc oxide (ZnO) or zinc hydroxide (Zn(OH) ₂ ), and these products are dissolved in a large amount in the strong alkaline electrolyte; during the charge process, due to These products have great solubility in alkaline electrolyte solution. After being dissolved in alkaline electrolyte solution, they become zincates such as potassium zincate or sodium zincate. Most of the zinc in the oxidation state will not deposit on the original dissolved zinc. position, the dissolved amount of zinc at the edge of the electrode is greater than the deposited amount, and the opposite is true at the center of the electrode, resulting in the redistribution of zinc on the electrode, which is manifested by the accumulation of active materials around the electrode to the center of the electrode. The active material at the edge is constantly decreasing, while the active material at the center of the electrode is constantly increasing, resulting in electrode deformation, which leads to a decrease in the surface area for electrochemical reactions, which reduces the discharge rate and battery capacity, and shortens the battery cycle life. In addition, the zincate partially deposited around the electrolyte and in the separator made the mass transfer process of the zinc electrode difficult and formed dendritic deposits on the external surface and some points of the electrode, easily piercing the separator.

In order to solve the above problems, US3873367 discloses a negative electrode of an alkaline storage battery, which includes an active material selected from the group consisting of metal zinc and zinc compounds, and mixed with another energy Reactants of alkaline earth metals that form refractory zincates on the path of zinc into solution, the proportion of the active species gradually decreases to zero from the inside to the outside of the electrode; the proportion of the reactants goes from the inside to the outside of the electrode Gradually increase to 100%. wherein said reactant is calcium.

The method is to add calcium hydroxide or magnesium hydroxide to the electrode, so that the discharge product of zinc and calcium hydroxide or magnesium hydroxide form insoluble calcium zincate and magnesium zincate, because calcium zincate and magnesium zincate are It does not dissolve in the electrolyte, but deposits on the surface or inside of the zinc electrode. Thereby reducing the solubility of zinc discharge products in the electrolyte solution.

US5302475 discloses a kind of rechargeable battery, and this battery comprises the electrode that contains active material zinc, and a kind of alkaline electrolytic solution, and described battery can suppress the deformation of zinc electrode, and described electrolytic solution comprises: a) concentration is about 3M b) potassium fluoride at a concentration of about 1.8M; and c) potassium carbonate at a concentration of about 1.8M.

US5302475 discloses a battery, which includes an anode, a cathode and an electrolyte; the anode uses zinc or zinc alloy as an active material, the cathode contains a metal oxide or hydroxide as an active material, and the electrolyte contains a A salt solution obtained by reacting one or more acids from the group consisting of boric acid, phosphoric acid, arsenic acid with a hydroxide of an alkali metal or alkaline earth metal, the excess hydroxide present in the electrolyte being in the range of 0.02-3.0 equivalents / liter range.

US4273841 discloses a secondary electrochemical cell, wherein an active substance in the electrode is zinc, and the electrolyte includes 5-10% by weight of potassium hydroxide, 5-15% by weight of potassium fluoride and 10-20% by weight aqueous solution of potassium phosphate.

US5302475, US5302475, and US4273841 all introduce some ions into the electrolyte, such as fluoride ions, carbonate ions, phosphate ions, borate ions, arsenate ions, silicate ions, etc., and these ions can form with zinc discharge products Insoluble products reduce the solubility of zinc discharge products in the electrolyte solution, thereby inhibiting electrode deformation.

Although the above method can inhibit the deformation of the zinc electrode, after many cycles of the battery, the remaining rate of the zinc electrode area is not high, and the battery capacity decays quickly, so the effect of using the above method to suppress the deformation of the zinc electrode is still unsatisfactory. .

In addition, the method disclosed in US3873367 adds calcium hydroxide to the electrode. Although it can suppress the deformation of the zinc electrode to a certain extent, the more substances that cannot participate in the discharge are added to the electrode, the less the zinc content is, and the released There is also less energy, resulting in a lower energy density of the electrode.

The methods disclosed in US5302475, US5302475, and US4273841 have introduced fluoride ions, carbonate ions, phosphate ions, borate ions, arsenate ions, and silicate ions in the electrolyte, and the conductivity of the electrolyte is affected by the concentration of potassium hydroxide. After the above ions are added, the concentration of potassium hydroxide in the solution will decrease, resulting in a decrease in the conductivity of the electrolyte and an increase in the internal resistance of the battery, so that it cannot be discharged at a high current, and the high current discharge performance of the battery is poor.

Contents of the invention

The object of the present invention is to overcome the defects of low remaining rate of zinc negative electrode area and fast decay of battery capacity after multiple cycles of secondary batteries that inhibit the deformation of zinc electrodes in the prior art, and provide a method that can more effectively inhibit the deformation of zinc electrodes, The invention relates to a secondary battery capable of increasing the residual ratio of the area of the zinc negative electrode of the secondary battery and slowing down the fading of the battery capacity after multiple cycles, the zinc negative electrode of the battery, and a preparation method thereof.

The negative electrode of the zinc negative electrode secondary battery provided by the present invention includes a current collector and a negative electrode material coated and/or filled on the current collector, the negative electrode material contains a negative electrode active material and a binder, and the negative electrode active material contains a zinc element And/or zinc oxide, wherein the negative electrode active material also contains a zinc salt insoluble in alkaline electrolyte.

The preparation method of the zinc negative electrode of the secondary battery provided by the present invention comprises coating and/or filling the slurry containing the negative active material, the binder and the solvent on the current collector, drying, calendering or not calendering, the negative active material It contains zinc element and/or zinc oxide, wherein the negative electrode active material also contains zinc salt insoluble in alkaline electrolyte.

The secondary battery provided by the present invention includes a pole core and an alkaline electrolyte, the pole core and the alkaline electrolyte are sealed in a battery casing, the pole core includes an electrode and a diaphragm of the battery, and the battery negative electrode includes a current collector and The negative electrode material coated and/or filled on the current collector, the negative electrode material contains negative electrode active material and binder, the negative electrode active material contains zinc element and/or zinc oxide, wherein, the negative electrode active material also contains insoluble Zinc salt in alkaline electrolyte.

The preparation method of the secondary battery provided by the present invention includes sealing the pole core and the electrolyte in the battery shell, the pole core includes a battery electrode and a diaphragm, and the preparation method of the battery negative pole includes combining an active material and a binder with a The solvent slurry is coated and/or filled on the current collector, dried, calendered or not calendered, the negative electrode active material contains zinc element and/or zinc oxide, wherein the negative electrode active material also contains an insoluble alkaline electrolyte zinc salt.

Since the zinc negative electrode provided by the present invention has added insoluble zinc salt in the alkaline electrolyte, during the discharge process of the battery, the discharge product of the active material zinc that enters the electrolyte solution and can be dissolved in the electrolyte solution is will deposit in the areas where it was originally left by dissolution. Because the oxidized zinc in the zinc salt added to the electrode is reduced to form crystal nuclei on the electrode for the deposition of zincate dissolved in the electrolyte solution. The zinc salt added to the electrode is evenly distributed in the electrode, so the crystal nuclei formed are evenly distributed in the electrode. Therefore, the discharge products of zinc dissolved in the electrolyte solution are evenly redeposited on the electrode during the charging process through these uniformly distributed crystal nuclei formed by the zinc salt added to the electrode, avoiding the tendency to deposit on the electrode. The middle part, therefore, effectively suppresses the deformation of the zinc electrode. Adding the zinc salt in the electrode can not only suppress the deformation of the zinc electrode well, but also, because the zinc salt contains a large amount of zinc, it has electrochemical activity, so it will not reduce the energy of the battery with this electrode as the negative pole. density. In addition, since the present invention does not change the electrolyte, and the zinc salt added to the electrode is not dissolved in the alkaline electrolyte, it will not reduce the solubility of potassium hydroxide in the electrolyte solution, and there will be no impact on the battery. The problem of high current discharge performance.

Detailed ways

According to the present invention, the insoluble zinc salt contained in the negative electrode active material is selected from one or more of zinc carbonate, zinc silicate, zinc phosphate and zinc borate.

According to the present invention, based on the total weight of the negative electrode active material, the content of the insoluble zinc salt in the electrolyte solution is 0.5-50% by weight, preferably 1-40% by weight.

According to the zinc negative electrode of the secondary battery provided by the present invention, the negative electrode material contains a negative electrode active material and a binder, and the negative electrode active material contains zinc simple substance and/or zinc oxide, wherein the negative electrode active material also contains an alkali-insoluble Zinc salts in neutral electrolytes.

The zinc element contained in the negative electrode active material, such as zinc powder, and/or zinc oxide is the conventional negative electrode active material in the zinc negative electrode secondary battery, in addition, it can also contain other conventional Negative active material.

The type and content of the negative electrode binder are known to those skilled in the art, for example, the binder can be selected from polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose , sodium polyacrylate, polytetrafluoroethylene; the content of the negative electrode binder is known to those skilled in the art, and is generally 0.01-10% by weight of the total weight of the negative electrode active material, preferably 0.02-8% by weight %.

The negative electrode material can also contain a conductive agent, the conductive agent is not particularly limited, and can be a conventional negative electrode conductive agent in the art, such as one or more of acetylene black, graphite, carbon black, copper powder, tin powder, etc. kind. Generally, based on the weight of the negative electrode active material, the content of the conductive agent is 0.1-15 wt%, preferably 0.5-10 wt%.

The negative electrode current collector can be a conventional negative electrode current collector in a secondary battery with zinc as the negative electrode, such as punched copper strip, copper braided mesh, or porous drawn copper mesh. In a specific embodiment of the present invention, a punched copper strip is used as the negative electrode current collector.

According to the present invention, the preparation method of the zinc negative electrode includes coating and/or filling the slurry containing the negative active material, the binder and the solvent on the current collector, drying, rolling or not rolling, and the negative active material contains Zinc element and/or zinc oxide, wherein the negative electrode active material also contains zinc salt insoluble in alkaline electrolyte. The zinc salt is selected from one or more of zinc carbonate, zinc silicate, zinc phosphate and zinc borate, preferably, the content of the zinc carbonate and zinc phosphate is no more than 25% of the total weight of the negative electrode active material; The content of the zinc silicate and zinc borate is no more than 20% of the total weight of the negative electrode active material. Wherein, the solvent may be selected from any solvent capable of forming the mixture into a paste, preferably water. The amount of the solvent can make the paste have viscosity and fluidity, and can be coated on the conductive substrate. Generally, the content of the solvent is 10-60% by weight of the negative electrode active material, preferably 15-55% by weight. Wherein, the method of coating and/or filling the slurry on the current collector, the method and conditions of drying and calendering are well known to those skilled in the art.

The zinc negative secondary battery provided by the present invention comprises a pole core, an alkaline electrolyte and a battery housing, the pole core and the alkaline electrolyte are sealed in the battery housing, and the pole core comprises a positive pole, a negative pole and a diaphragm, wherein , the negative pole is the zinc negative pole provided by the present invention.

According to the present invention, the preparation method of the zinc negative secondary battery includes sealing the pole core and the electrolyte in the battery case, the pole core includes the positive pole of the battery, the negative pole and the separator, and the preparation method of the negative pole of the battery comprises the following steps: Slurry coating and/or filling of active material, binder and solvent on the current collector, drying, calendering or not calendering, the negative electrode active material contains zinc simple substance and/or zinc oxide, wherein the negative electrode active material is also Contains zinc salts that are insoluble in alkaline electrolytes.

The zinc negative electrode of the present invention can be used in various secondary batteries, such as secondary zinc-silver battery, secondary zinc-manganese battery, zinc negative battery and the like.

Since the present invention only relates to the improvement of the battery zinc negative pole, there is no special limitation to the composition and structure of other parts of the battery. For example, the positive pole can contain positive active materials (such as nickel hydroxide, silver oxide, manganese dioxide One of them), binder and additives corresponding to the positive electrode active material (depending on which positive electrode active material is used, for example, when nickel hydroxide is used as the positive electrode active material, the corresponding additive is cobaltous oxide, conductive Carbon black or nickel powder) and deionized water are stirred into a slurry and coated on the foamed nickel welded with a drainage tape, and then dried, calendered, and cut into pieces to obtain a nickel positive electrode. The separator is arranged between the positive electrode and the negative electrode, has electrical insulation performance and liquid retention performance, and can block the penetration of zinc dendrites, and allows the electrode core and the alkaline electrolyte to be accommodated in the battery casing. The diaphragm can be selected from various composite diaphragms used in alkaline secondary batteries with zinc as the negative electrode, such as a composite diaphragm formed by combining various microporous membranes that can block the penetration of zinc dendrites and various liquid storage membranes , various microporous membranes can be selected from one or more of various microporous membranes known to those skilled in the art that can be wetted by alkaline electrolytes such as polypropylene microporous membranes treated with nonionic surfactants , or one or more of polyethylene radiation grafted membrane series, and can also be hydrated cellulose membrane, cellophane membrane or polyvinyl alcohol membrane. The other part of the liquid storage membrane combined into the composite diaphragm can be selected from modified polypropylene felt, vinylon felt or nylon felt for alkaline secondary batteries known to those skilled in the art. Composite diaphragms are sheet-like elements. The location, nature and type of said septum are well known to those skilled in the art. The alkaline electrolyte solution may be an aqueous solution of at least one selected from KOH, NaOH and LiOH. The injection amount of the electrolyte is generally 0.9-4.5 g/Ah, and the concentration of the electrolyte is generally 6-8 mol/liter.

The battery casing can be various casings suitable for various types of batteries, and those skilled in the art can easily select a suitable battery casing according to needs.

The following examples will further illustrate the present invention.

Example 1

This example illustrates the secondary battery and its zinc negative electrode provided by the present invention and their preparation methods.

(1) Preparation of negative electrode

70 grams of zinc oxide, 20 grams of zinc carbonate and 3 grams of conductive carbon black are mixed in a blender as the negative electrode active material, and then mixed with 20 grams of 3% by weight polyvinyl alcohol aqueous solution, 25 grams of 2% by weight of hydroxypropyl methylcellulose Aqueous plain solution, 4.8 grams of polytetrafluoroethylene and 5 grams of deionized water were stirred into a viscous slurry. Then apply the above slurry on a punched copper strip with a thickness of 0.07mm and a width of 42mm coated with a Pb-Sn alloy coating, then dry, roll, cut into pieces and weld the drainage strip at 105°C A negative electrode sheet with a size of 95 mm×42 mm×0.6 mm was prepared. The negative electrode contained 5 grams of negative electrode material.

(2) Preparation of positive electrode

Fully stir 92 grams of spherical nickel hydroxide, 7 grams of cobaltous oxide, 11 grams of conductive carbon black and 3 grams of polytetrafluoroethylene, 0.2 grams of sodium carboxymethylcellulose and 52 grams of deionized water, and mix to form a slurry And apply it on the foamed nickel welded with drainage tape, then dry at 105°C, calender, and cut into pieces to prepare positive pole pieces with a size of 65mm×40mm×0.6mm. The positive electrode contained 4.5 grams of positive electrode material.

(3) Battery assembly

The negative electrode obtained in (1), the wettable polyolefin microporous membrane compounded with vinylon felt, and the positive electrode obtained in (2) are sequentially stacked and wound into a scroll-shaped electrode core, and the obtained electrode core is placed in a container with one end open. Add 1.1g/Ah of electrolyte to the steel case of AA battery (the electrolyte is a mixed aqueous solution of KOH and LiOH, and the mixed aqueous solution contains 30% by weight of KOH and 1.5% by weight of LiOH), and seal it to make AA-shaped cylindrical zinc-nickel battery A1.

Example 2

This example illustrates the secondary battery and its zinc negative electrode provided by the present invention and their preparation methods.

(1) Preparation of negative electrode

75 grams of zinc oxide, 10 grams of zinc silicate, 10 grams of zinc carbonate and 3 grams of conductive carbon black are mixed in a blender as the negative electrode active material, and then mixed with 20 grams of 3% by weight polyvinyl alcohol aqueous solution, 25 grams of 2% by weight of An aqueous solution of hydroxypropyl methylcellulose, 4.8 grams of polytetrafluoroethylene and 5 grams of deionized water were stirred to form a thick slurry. Then apply the above slurry on a punched copper strip with a thickness of 0.07mm and a width of 42mm coated with a Pb-Sn alloy coating, then dry, roll, cut into pieces and weld the drainage strip at 105°C A negative electrode sheet with a size of 95 mm×42 mm×0.6 mm was prepared. The negative electrode sheet contains 5 grams of negative electrode material.

(2) Preparation of positive electrode

Fully stir 92 grams of spherical nickel hydroxide, 7 grams of cobaltous oxide, 11 grams of conductive carbon black and 3 grams of polytetrafluoroethylene, 0.2 grams of sodium carboxymethylcellulose and 52 grams of deionized water, and mix to form a slurry And apply it on the foamed nickel welded with drainage tape, then dry at 105°C, calender, and cut into pieces to prepare positive pole pieces with a size of 65mm×40mm×0.6mm. The positive electrode sheet contains 4.5 grams of positive electrode material.

(3) Battery assembly

The negative electrode obtained in (1), the wettable polyolefin microporous membrane compounded with vinylon felt, and the positive electrode obtained in (2) are sequentially stacked and wound into a scroll-shaped electrode core, and the obtained electrode core is placed in a container with one end open. Add 1.1g/Ah of electrolyte to the steel case of AA battery (the electrolyte is a mixed aqueous solution of KOH and LiOH, and the mixed aqueous solution contains 30% by weight of KOH and 1.5% by weight of LiOH), and seal it to make AA-shaped cylindrical zinc-nickel Battery A2.

Example 3

This example illustrates the secondary battery and its zinc negative electrode provided by the present invention and their preparation methods.

(1) Preparation of negative electrode

75 grams of zinc oxide, 15 grams of zinc phosphate and 3 grams of conductive carbon black in the negative active material are mixed uniformly in a blender and then mixed with 20 grams of 3% by weight polyvinyl alcohol aqueous solution, 25 grams of 2% by weight of hydroxypropyl methylcellulose Aqueous plain solution, 3.0 grams of polytetrafluoroethylene and 5 grams of deionized water were stirred into a viscous slurry. Then apply the above slurry on a punched copper strip with a thickness of 0.07mm and a width of 42mm coated with a Pb-Sn alloy coating, then dry, roll, cut into pieces and weld the drainage strip at 105°C A negative electrode sheet with a size of 95 mm×42 mm×0.6 mm was prepared. The negative electrode sheet contains 5 grams of negative electrode material.

(2) Preparation of positive electrode

Fully stir 92 grams of spherical nickel hydroxide, 7 grams of cobaltous oxide, 11 grams of conductive carbon black and 3 grams of polytetrafluoroethylene, 0.2 grams of sodium carboxymethylcellulose and 52 grams of deionized water, and mix to form a slurry And apply it on the foamed nickel welded with drainage tape, then dry at 105°C, calender, and cut into pieces to prepare positive pole pieces with a size of 65mm×40mm×0.6mm. The positive electrode sheet contains 4.5 grams of positive electrode material.

(3) Battery assembly

The negative electrode obtained in (1), the wettable polyolefin microporous membrane compounded with vinylon felt, and the positive electrode obtained in (2) are sequentially stacked and wound into a scroll-shaped electrode core, and the obtained electrode core is placed in a container with one end open. Add 1.1g/Ah of electrolyte to the steel case of AA battery (the electrolyte is a mixed aqueous solution of KOH and LiOH, and the mixed aqueous solution contains 30% by weight of KOH and 1.5% by weight of LiOH), and seal it to make AA-shaped cylindrical zinc-nickel Battery A3.

Example 4

This example illustrates the secondary battery and its zinc negative electrode provided by the present invention and their preparation methods.

(1) Preparation of negative electrode

75 grams of zinc oxide, 5 grams of zinc carbonate, 5 grams of zinc silicate, 8 grams of zinc phosphate, 7 grams of zinc borate and 3 grams of conductive carbon black are mixed in a mixer and then mixed with 20 grams of 3% by weight poly Aqueous vinyl alcohol, 25 grams of 2% by weight hydroxypropyl methylcellulose aqueous solution, 4.8 grams of polytetrafluoroethylene, and 5 grams of deionized water were stirred into a viscous slurry. Then apply the above slurry on a punched copper strip with a thickness of 0.07mm and a width of 42mm coated with a Pb-Sn alloy coating, then dry, roll, cut into pieces and weld the drainage strip at 105°C A negative electrode sheet with a size of 95 mm×42 mm×0.6 mm was prepared. The negative electrode sheet contains 5 grams of negative electrode material.

(2) Preparation of positive electrode

Fully stir 92 grams of spherical nickel hydroxide, 7 grams of cobaltous oxide, 11 grams of conductive carbon black and 3 grams of polytetrafluoroethylene, 0.2 grams of sodium carboxymethylcellulose and 52 grams of deionized water, and mix to form a slurry And apply it on the foamed nickel welded with drainage tape, then dry at 105°C, calender, and cut into pieces to prepare positive pole pieces with a size of 65mm×40mm×0.6mm. The positive electrode sheet contains 4.5 grams of positive electrode material.

(3) Battery assembly

The negative electrode obtained in (1), the wettable polyolefin microporous membrane compounded with vinylon felt, and the positive electrode obtained in (2) are sequentially stacked and wound into a scroll-shaped electrode core, and the obtained electrode core is placed in a container with one end open. Add 1.1g/Ah of electrolyte to the steel case of AA battery (the electrolyte is a mixed aqueous solution of KOH and LiOH, and the mixed aqueous solution contains 30% by weight of KOH and 1.5% by weight of LiOH), and seal it to make AA-shaped cylindrical zinc-nickel Battery A4.

Example 5

This example illustrates the secondary battery and its zinc negative electrode provided by the present invention and their preparation methods.

(1) Preparation of negative electrode

75 grams of zinc oxide, 5 grams of zinc phosphate, 15 grams of zinc borate and 3 grams of conductive carbon black are mixed in a blender as the negative electrode active material, and then mixed with 20 grams of 3% by weight polyvinyl alcohol aqueous solution, 25 grams of 2% by weight of hydroxy An aqueous solution of propyl methylcellulose, 4.8 grams of polytetrafluoroethylene, and 5 grams of deionized water were stirred into a viscous slurry. Then apply the above slurry on a punched copper strip with a thickness of 0.07mm and a width of 42mm coated with a Pb-Sn alloy coating, then dry, roll, cut into pieces and weld the drainage strip at 105°C A negative electrode sheet with a size of 95 mm×42 mm×0.6 mm was prepared. The negative electrode sheet contains 5 grams of negative electrode material.

(2) Preparation of positive electrode

Fully stir 92 grams of spherical nickel hydroxide, 7 grams of cobaltous oxide, 11 grams of conductive carbon black and 3 grams of polytetrafluoroethylene, 0.2 grams of sodium carboxymethylcellulose and 52 grams of deionized water, and mix to form a slurry And apply it on the foamed nickel welded with drainage tape, then dry at 105°C, calender, and cut into pieces to prepare positive pole pieces with a size of 65mm×40mm×0.6mm. The positive electrode sheet contains 4.5 grams of positive electrode material.

(3) Battery assembly

The negative electrode obtained in (1), the wettable polyolefin microporous membrane compounded with vinylon felt, and the positive electrode obtained in (2) are sequentially stacked and wound into a scroll-shaped electrode core, and the obtained electrode core is placed in a container with one end open. Add 1.1g/Ah of electrolyte to the steel case of AA battery (the electrolyte is a mixed aqueous solution of KOH and LiOH, and the mixed aqueous solution contains 30% by weight of KOH and 1.5% by weight of LiOH), and seal it to make AA-shaped cylindrical zinc-nickel Battery A5.

Example 6

This example illustrates the secondary battery and its zinc negative electrode provided by the present invention and their preparation methods.

(1) Preparation of negative electrode

85 grams of zinc oxide, 5 grams of zinc carbonate and 3 grams of conductive carbon black are mixed in a blender as the negative active material, and then mixed with 20 grams of 3% by weight polyvinyl alcohol solution, 25 grams of 2% by weight of hydroxypropyl methylcellulose Aqueous plain solution, 4.8 grams of polytetrafluoroethylene and 5 grams of deionized water were stirred into a viscous slurry. Then apply the above slurry on a punched copper strip with a thickness of 0.07mm and a width of 42mm coated with a Pb-Sn alloy coating, then dry, roll, cut into pieces and weld the drainage strip at 105°C A negative electrode sheet with a size of 95 mm×42 mm×0.6 mm was prepared. The negative electrode sheet contains 5 grams of negative electrode material.

(2) Preparation of positive electrode

Fully stir 92 grams of spherical nickel hydroxide, 7 grams of cobaltous oxide, 11 grams of conductive carbon black and 3 grams of polytetrafluoroethylene, 0.2 grams of sodium carboxymethylcellulose and 52 grams of deionized water, and mix to form a slurry And apply it on the foamed nickel welded with drainage tape, then dry at 105°C, calender, and cut into pieces to prepare positive pole pieces with a size of 65mm×40mm×0.6mm. The positive electrode sheet contains 4.5 grams of positive electrode material.

(3) Battery assembly

The negative electrode obtained in (1), the wettable polyolefin microporous membrane compounded with vinylon felt, and the positive electrode obtained in (2) are sequentially stacked and wound into a scroll-shaped electrode core, and the obtained electrode core is placed in a container with one end open. Add 1.1g/Ah of electrolyte to the steel case of AA battery (the electrolyte is a mixed aqueous solution of KOH and LiOH, and the mixed aqueous solution contains 30% by weight of KOH and 1.5% by weight of LiOH), and seal it to make AA-shaped cylindrical zinc-nickel Battery A6.

Example 7

This example illustrates the secondary battery and its zinc negative electrode provided by the present invention and their preparation methods.

(1) Preparation of negative electrode

75 grams of zinc oxide, 15 grams of zinc silicate, 5 grams of zinc borate and 3 grams of conductive carbon black are mixed in a blender as the negative electrode active material, and then mixed with 20 grams of 3% by weight polyvinyl alcohol aqueous solution, 25 grams of 2% by weight of An aqueous solution of hydroxypropyl methylcellulose, 4.8 grams of polytetrafluoroethylene and 5 grams of deionized water were stirred into a viscous slurry. Then apply the above slurry on a punched copper strip with a thickness of 0.07mm and a width of 42mm coated with a Pb-Sn alloy coating, then dry, roll, cut into pieces and weld the drainage strip at 105°C A negative electrode sheet with a size of 95 mm×42 mm×0.6 mm was prepared. The negative electrode sheet contains 5 grams of negative electrode material.

(2) Preparation of positive electrode

Fully stir 92 grams of spherical nickel hydroxide, 7 grams of cobaltous oxide, 11 grams of conductive carbon black and 3 grams of polytetrafluoroethylene, 0.2 grams of sodium carboxymethylcellulose and 52 grams of deionized water, and mix to form a slurry And apply it on the foamed nickel welded with drainage tape, then dry at 105°C, calender, and cut into pieces to prepare positive pole pieces with a size of 65mm×40mm×0.6mm. The positive electrode sheet contains 4.5 grams of positive electrode material.

(3) Battery assembly

The negative electrode obtained in (1), the wettable polyolefin microporous membrane compounded with vinylon felt, and the positive electrode obtained in (2) are sequentially stacked and wound into a scroll-shaped electrode core, and the obtained electrode core is placed in a container with one end open. Add 1.1g/Ah of electrolyte to the steel case of AA battery (the electrolyte is a mixed aqueous solution of KOH and LiOH, and the mixed aqueous solution contains 30% by weight of KOH and 1.5% by weight of LiOH), and seal it to make AA-shaped cylindrical zinc-nickel Battery A7.

Example 8

This example illustrates the secondary battery and its zinc negative electrode provided by the present invention and their preparation methods.

(1) Preparation of negative electrode

75 grams of zinc oxide, 20 grams of zinc carbonate, 20 grams of zinc borate and 3.5 grams of conductive carbon black are mixed in a blender as the negative electrode active material, and then mixed with 20 grams of 3% by weight polyvinyl alcohol aqueous solution, 25 grams of 2% by weight of hydroxyl An aqueous solution of propyl methylcellulose, 5.0 grams of polytetrafluoroethylene and 5 grams of deionized water were stirred to form a thick slurry. Then apply the above slurry on a punched copper strip with a thickness of 0.07mm and a width of 42mm coated with a Pb-Sn alloy coating, then dry, roll, cut into pieces and weld the drainage strip at 105°C A negative electrode sheet with a size of 95 mm×42 mm×0.6 mm was prepared. The negative electrode sheet contains 5 grams of negative electrode material.

(2) Preparation of positive electrode

Fully stir 92 grams of spherical nickel hydroxide, 7 grams of cobaltous oxide, 11 grams of conductive carbon black and 3 grams of polytetrafluoroethylene, 0.2 grams of sodium carboxymethylcellulose and 52 grams of deionized water, and mix to form a slurry And apply it on the foamed nickel welded with drainage tape, then dry at 105°C, calender, and cut into pieces to prepare positive pole pieces with a size of 65mm×40mm×0.6mm. The positive electrode sheet contains 4.5 grams of positive electrode material.

(3) Battery assembly

The negative electrode obtained in (1), the wettable polyolefin microporous membrane compounded with vinylon felt, and the positive electrode obtained in (2) are sequentially stacked and wound into a scroll-shaped electrode core, and the obtained electrode core is placed in a container with one end open. Add 1.1g/Ah of electrolyte to the steel case of AA battery (the electrolyte is a mixed aqueous solution of KOH and LiOH, and the mixed aqueous solution contains 30% by weight of KOH and 1.5% by weight of LiOH), and seal it to make AA-shaped cylindrical zinc-nickel Battery A8.

Comparative example 1

The positive, negative and separator layers of the battery were prepared according to the method of Example 1 and assembled into a reference battery AC1, except that no zinc salt insoluble in the electrolyte was added to the zinc electrode.

Comparative example 2

The positive, negative and separator layers of the battery were prepared according to the method of Example 1 and assembled into a reference battery AC2, except that 20 grams of calcium hydroxide was added to the zinc electrode.

Performance Testing

Performance tests were performed on the secondary batteries A1-A8 prepared in Examples 1-8 and the reference batteries AC1 and AC2 prepared in Comparative Examples 1-2, respectively.

Battery activation:

The secondary batteries A1-A8 made in Examples 1-8 and the reference batteries AC1 and AC2 made in Comparative Example 1-2 were charged with a current of 70 mA for 16 hours, and then discharged to a battery voltage of 1.3 with a current of 350 mA. volts to activate.

Battery performance test:

The activated batteries A1-A8 and AC1 and AC2 were charged with a current of 140mA respectively, and left for 10 minutes, and then discharged to 1.3 volts with a current of 700mA, and left for 5 minutes. The above-mentioned steps were repeated 250 times.

(1) Dissect the battery and measure the electrode area on the zinc electrode where the current collector is not exposed, which is designated as S1. And calculate the area remaining rate of the zinc electrode after 250 cycles with the initial area S (95×42 mm) of the electrode according to the formula area remaining rate=(S1/S)×100%.

(2) Obtain the battery capacity after 250 cycles, and calculate the battery capacity maintenance rate before and after the cycle by the following formula:

Capacity retention rate = (250th cycle discharge capacity / first cycle discharge capacity) × 100%

The results are shown in Table 1.

Table 1

instance number First cycle discharge capacity (mAh) 250th cycle discharge capacity (mAh) Capacity maintenance rate (%) Remaining rate of zinc electrode area (%) Example 1 750 619 82.5 83 Example 2 730 614 84.1 85 Example 3 735 636 86.5 88 Example 4 752 632 84 87 Example 5 742 611 82.3 87 Example 6 731 589 80.6 82 Example 7 744 618 83.1 85 Example 8 747 620 83.0 86 Comparative example 1 735 362 49.3 52 Comparative example 2 680 504 74.1 75

As can be seen from the results shown in Table 1, the secondary battery provided by the present invention is compared with the reference battery, and after 250 cycles, the remaining rate of the zinc negative electrode area is significantly higher than that of the reference battery, and the battery capacity decays slowly , the battery cycle performance is good.

Claims (10)

1. A zinc negative electrode for a secondary battery, the negative electrode includes a current collector and a negative electrode material coated and/or filled on the current collector, the negative electrode material contains a negative electrode active material and a binder, and the negative electrode active material contains zinc Simple substance and/or zinc oxide, wherein the negative electrode active material also contains zinc salt insoluble in alkaline electrolyte. 2. The negative electrode according to claim 1, wherein the zinc salt insoluble in the alkaline electrolyte is selected from one or more of zinc carbonate, zinc silicate, zinc phosphate and zinc borate. 3. The negative electrode according to claim 1, wherein, based on the total weight of the negative electrode active material, the content of the zinc salt insoluble in alkaline electrolyte is 0.5-50% by weight. 4. The negative electrode according to claim 3, wherein, based on the total weight of the negative electrode active material, the content of the zinc salt insoluble in alkaline electrolyte is 1-40% by weight. 5. The preparation method of the zinc negative electrode according to claim 1 comprises coating and/or filling the slurry containing the negative active material, the binder and the solvent on the current collector, drying, calendering or not calendering, the negative active material It contains zinc element and/or zinc oxide, wherein the negative electrode active material also contains zinc salt insoluble in alkaline electrolyte. 6. The method according to claim 5, wherein the zinc salt insoluble in the alkaline electrolyte is selected from one or more of zinc carbonate, zinc silicate, zinc phosphate and zinc borate. 7. A secondary battery, the battery includes a pole core and an alkaline electrolyte, the pole core and the alkaline electrolyte are sealed in a battery casing, the pole core includes an electrode and a diaphragm of the battery, and the battery negative electrode includes A current collector and a positive electrode material coated and/or filled on the current collector, the negative electrode material contains a negative electrode active material and a binder, and the negative electrode active material contains zinc simple substance and/or zinc oxide, wherein the negative electrode active material Also contains zinc salts which are insoluble in alkaline electrolytes. 8. The battery according to claim 7, wherein the zinc salt insoluble in the alkaline electrolyte is selected from one or more of zinc carbonate, zinc silicate, zinc phosphate and zinc borate. 9. The preparation method of the secondary battery according to claim 7, the method comprises sealing the pole core and the electrolyte in the battery casing, the pole core includes the battery electrode and the diaphragm, and the preparation method of the battery negative electrode comprises Slurry coating and/or filling of active material, binder and solvent on the current collector, drying, calendering or not calendering, the negative electrode active material contains zinc simple substance and/or zinc oxide, wherein the negative electrode active material is also Contains zinc salts that are insoluble in alkaline electrolytes. 10. The method according to claim 9, wherein the zinc salt insoluble in the alkaline electrolyte is selected from one or more of zinc carbonate, zinc silicate, zinc phosphate and zinc borate.