CN103647054B - A kind of nickel radical battery positive pole and preparation method thereof and the nickel radical battery using this positive pole - Google Patents

Abstract

The invention discloses a kind of nickel radical battery positive pole and preparation method thereof and the nickel radical battery using this positive pole.Drip irrigation device of the present invention is: a kind of nickel radical battery positive pole, comprise positive electrode active materials, described positive electrode active materials contains nickel hydroxide and soluble calcium salt calcium metaborate or line borate, and wherein the content of soluble calcium salt calcium metaborate or line borate is the 0.01%-5% of weight of nickel hydroxide.The invention also discloses the preparation method of this nickel radical battery positive pole and use the Ni-based secondary cell of the alkalescence of this nickel radical battery positive pole.In soluble calcium salt of the present invention calcium ion be uniformly distributed the combination property effectively can improving nickel radical battery with the introducing of useful anion, comprise and reduce nickel radical battery internal resistance, improve high-temperature behavior and improve cycle performance.

Description

A nickel-based battery positive electrode, its preparation method, and a nickel-based battery using the positive electrode

technical field

The invention belongs to the technical field of nickel-based batteries, and in particular relates to a nickel-based battery positive electrode, a preparation method thereof and a nickel-based battery using the positive electrode.

Background technique

Existing alkaline nickel-based secondary batteries include cadmium-nickel batteries, hydrogen-nickel batteries, zinc-nickel batteries, and iron-nickel batteries, etc., which have different performances and application paths, and are widely used in people's daily life and industrial production. Each is at a different stage of development. Since the negative electrode contains toxic cadmium, nickel-cadmium batteries will cause environmental problems of heavy metal pollution. At present, they are gradually replaced by nickel-hydrogen batteries and are beginning to withdraw from the market. The negative electrode of the hydrogen-nickel battery uses hydrogen storage alloy as the active material, which has high capacity and excellent electrical properties, and is environmentally friendly. It is widely used in civilian and electric vehicles and other fields. It is currently the fastest growing and most widely used The most mature nickel-based secondary battery. In recent years, with the advancement of zinc anode technology and the improvement of its performance, zinc-nickel batteries, which have a history of nearly a hundred years, have come into people's field of vision again, have received more attention, and are currently in a period of vigorous development. Due to the best cost performance, iron-nickel batteries have received more and more attention in recent years as people's research on iron negative electrodes has made continuous progress, and they are still in the research and development stage. The common feature of alkaline nickel-based secondary batteries is that they all use nickel hydroxide active material as the positive electrode, and the preparation methods of the positive electrode are similar; in addition, nickel-based secondary batteries are all limited to the positive limit, that is to say, the discharge performance of the positive electrode Determines the capacity of nickel-based batteries, therefore, the improved technology for nickel hydroxide positive electrode is equally applicable to different nickel-based batteries.

In recent years, the improvement of the high-temperature performance of nickel-based secondary batteries has attracted people's attention. The study found that the main factor restricting the high-temperature performance of nickel-based batteries is the decrease in the oxygen evolution potential of the positive electrode in a high-temperature environment. Therefore, the main way to improve the high temperature performance of nickel-based batteries is to increase the oxygen evolution potential of the positive electrode and improve the charging efficiency of the nickel positive electrode under high temperature conditions. In the prior art, the high-temperature performance of the positive electrode of the nickel-based battery is improved by doping, covering and using additives in the nickel hydroxide active material. Among them, doping and coating of rare earth elements, modification of cobalt compounds, etc. These methods can improve the oxygen evolution potential of the positive electrode of the nickel-based battery to a certain extent and improve the high-temperature charging efficiency. However, the cost of rare earth elements is high, the coating method is complicated, and the preparation cost is relatively high. Therefore, these methods will significantly increase the cost of nickel-based batteries to some extent. In recent years, cheap calcium salts have attracted people's attention due to the same effect of improving the high-temperature charging efficiency of the nickel-based battery cathode.

For example, CN101357781A discloses a spherical nickel hydroxide for high-temperature nickel batteries, by coating insoluble metal fluoride salts, such as calcium fluoride, on the surface of nickel hydroxide; CN101357780A discloses a spherical nickel hydroxide for high-temperature nickel batteries , by coating insoluble phosphate, such as calcium phosphate, on the surface of nickel hydroxide; CN102760874A discloses a spherical nickel hydroxide for high-temperature nickel batteries, by modifying calcium carbonate on the surface of nickel hydroxide. At the same time, there are also reports in the literature that the insoluble calcium salt calcium hydroxide, calcium carbonate or calcium fluoride is directly added to the positive electrode of the nickel-based battery as the positive electrode additive. These methods have all achieved certain effects in improving the high-temperature performance of nickel-based batteries. However, the method of coating insoluble calcium salts is complicated in process, harsh in conditions, and high in cost. Therefore, industrial production usually adopts the method of doping with insoluble calcium salts (such as calcium hydroxide, calcium carbonate or calcium fluoride, etc.). However, since calcium salts are non-conductive substances, it is difficult for a small amount of insoluble calcium salt particles to mix evenly with a large number of micron-sized nickel hydroxide particles. The conductive network causes the internal resistance of the nickel-based battery to increase and the cycle life to deteriorate. Therefore, although the cost of doping insoluble calcium salt is lower than that of the coating process, the uniformity of calcium ion distribution in the nickel-based battery positive electrode is poor, and further improvement is needed.

Contents of the invention

In order to solve the deficiencies of the prior art, the present invention provides a nickel-based battery positive electrode modified with soluble calcium salts and a preparation method thereof, which solves the problem of the complex preparation process of calcium salt-coated nickel hydroxide in the prior art and the insoluble calcium The uneven dispersion of the salt additive causes the technical problem of relatively high internal resistance of the nickel-based battery. In addition, the invention also provides an alkaline nickel-based secondary battery prepared by using the positive electrode of the nickel-based battery.

The technical scheme of the present invention is: a positive electrode of a nickel-based battery, including a positive electrode active material, characterized in that: the positive electrode active material contains nickel hydroxide and soluble calcium salt calcium metaborate or calcium borate, wherein the soluble calcium salt metaboric acid The content of calcium or calcium borate is 0.01%-5% of the weight of nickel hydroxide.

A method for preparing a positive electrode of a nickel-based battery, characterized by comprising the following steps: (1) uniformly mixing 100 parts by weight of nickel hydroxide and 0.5-10 parts by weight of a conductive agent to obtain a semi-finished mixture; (2) mixing 0.5-5 parts by weight Parts by weight of hydrophilic binder and 0.01-5 parts by weight of soluble calcium salt are mixed uniformly and dissolved in 10-30 parts by weight of deionized water; (3) adding the semi-finished product mixture prepared in step (1) to step (2) Add 0.1-2 parts by weight of hydrophobic binder to the obtained solution under stirring conditions, and prepare a slurry with good fluidity after sufficient stirring; (4) Mix the slurry prepared in step (3) Coated on the positive electrode current collector through slurrying or drawing process, dried, pressed, and cut into nickel-based battery positive electrodes of required size, wherein the conductive agent described in step (1) is cobaltous oxide or T255 nickel powder or a mixture of the two, the hydrophilic binder described in step (2) is sodium carboxymethylcellulose (CMC) or hydroxypropyl methylcellulose (HPMC), and the soluble calcium salt is Calcium metaborate or calcium borate, the hydrophobic binder described in step (3) is polytetrafluoroethylene (PTFE) emulsion, the positive electrode current collector described in step (4) is foamed nickel, fiber nickel or punched Hole nickel-plated steel strip.

As a preference, the soluble calcium salt selected in the present invention is further preferably calcium metaborate. Studies have found that metaborate is beneficial to the improvement of the performance of the positive electrode of the nickel-based battery, especially the improvement of the oxygen evolution potential.

Preferably, the hydrophobic binder used in the present invention is CMC or HPMC, and in view of the good compatibility between HPMC and calcium metaborate, HPMC is further preferred.

A nickel-based battery, comprising a battery case, an electrode group sealed in the battery case and an electrolyte, the electrode group comprising a positive pole, a negative pole and a diaphragm, characterized in that the positive pole adopts the nickel provided by the present invention positive terminal of the base battery. In view of the small difference in the production method and formula of the nickel-based battery positive electrode, the nickel-based battery positive electrode prepared by the invention is equally applicable to alkaline nickel-based secondary batteries including cadmium-nickel batteries, hydrogen-nickel batteries, zinc-nickel batteries and iron-nickel batteries. This is well known to those skilled in the art.

In the preparation method of the positive electrode of the nickel-based battery of the present invention, by adding soluble calcium salts in the slurry mixing process, the calcium ions can be easily and uniformly mixed in the positive electrode slurry, after drawing or coating slurry, drying, pressing, Cut into plates. Due to the excellent dispersibility of the soluble calcium salt, the distribution of calcium ions in the final plate is very uniform, and the adverse effect on the conductivity of the positive electrode is much smaller than that of the insoluble calcium salt. After assembling an alkaline secondary battery, add lye, at this time, the calcium ions in the positive plate will form calcium hydroxide with the hydroxide ions in the lye, which will be evenly distributed on the surface of the active material, so that the previously added The evenly distributed calcium ions are transformed into evenly distributed calcium hydroxide (because there may be carbonate groups in the lye, a small part of calcium carbonate will also be formed). The invention is based on the selection of soluble calcium salts based on beneficial anions. It has been found that the introduction of anions such as metaborate and borate is beneficial to the improvement of the electrical properties of the nickel-based battery positive electrode, while other soluble calcium salts, For example, calcium nitrate or calcium chloride will introduce anions that cause the performance of nickel-based batteries to deteriorate. For example, nitrate will seriously affect the self-discharge performance of nickel-based batteries. In a word, the method for preparing the positive electrode of the nickel-based battery provided by the present invention has obvious effect on improving the performance of the positive electrode, and the steps are simple and easy to implement.

The beneficial effects of the present invention compared with the prior art are: the preparation method of the present invention has simple steps, is easy to implement, the uniform distribution of calcium ions and the introduction of beneficial anions can effectively improve the overall performance of nickel-based batteries, including reducing the internal resistance of nickel-based batteries , improve high temperature performance and improve cycle performance. The method solves the difficulty in dispersion caused by the use of insoluble calcium salt in the preparation of the positive electrode of the alkaline nickel-based secondary battery, the high internal resistance of the nickel-based battery, and the poor cycle performance. Faced with problems such as high cost, complicated process, and harsh conditions.

Description of drawings

Fig. 1 is a comparison diagram of EDX calcium ion distribution of the nickel-based battery positive electrode prepared in Example 1 of the present invention and the nickel-based battery positive electrode prepared in Example 6.

Detailed ways

The above content of the present invention will be described in further detail below through specific implementation in the form of examples, but it should not be understood that the scope of the above subject of the present invention is limited to the following examples. All technologies realized based on the above content of the present invention belong to the scope of the present invention.

Example 1

Preparation of positive electrode: (1) Mix 100g of spherical nickel hydroxide, 5g of cobaltous oxide and 5g of T255 nickel powder to make active material mixture; (2) mix 1.0g of calcium metaborate and 2.5g of hydroxypropylmethyl After the cellulose is mixed evenly, add it to 20g of deionized water, and stir to form a uniform aqueous solution; (3) Add the active material mixture prepared in step (1) to the aqueous solution in step (2), and add 1.0g polytetrafluoroethylene The vinyl fluoride emulsion is mixed evenly to make a slurry; (4) A positive electrode product with a length and width of 90mm×42mm is prepared through processes such as pulp drawing, drying, cutting, powder cleaning, and electrode ear welding.

Preparation of the negative electrode: The hydrogen storage alloy powder is rolled onto the copper grid of the negative electrode substrate using the nickel-metal hydride battery dry negative electrode process, and a layer of polytetrafluoroethylene emulsion is soaked on the surface. After drying and rolling, it is cut into pieces. The finished negative electrode with a size of 125mm×42mm.

Battery assembly: the above-mentioned nickel positive electrode and hydrogen storage negative electrode are sandwiched by a sulfonated diaphragm made of PP material, wound into a multi-turn core by a winding machine and put into an AA-shaped steel case, and injected with a mass concentration of 30% KOH and The LiOH electrolyte with a mass concentration of 2% is finally sealed to make an AA1700 nickel-hydrogen battery.

Example 2

Production of the positive electrode: (1) Mix 100g of spherical nickel hydroxide, 0.25g of cobaltous oxide and 0.25g of T255 nickel powder to make an active material mixture; (2) Mix 0.01g of calcium borate and 0.5g of carboxymethyl fiber Mix plain sodium evenly and add to 10g of deionized water, stir to form a uniform aqueous solution; (3) Add the active material mixture prepared in step (1) to the aqueous solution in step (2), and add 0.1g of polytetrafluoroethylene The ethylene emulsion is mixed evenly to make a slurry; (4) A positive electrode product with a length and width of 90mm×42mm is prepared through processes such as pulp drawing, drying, cutting, powder cleaning, and electrode ear welding.

Preparation of the negative electrode: The hydrogen storage alloy powder is rolled onto the copper grid of the negative electrode substrate using the nickel-metal hydride battery dry negative electrode process, and a layer of polytetrafluoroethylene emulsion is soaked on the surface. After drying and rolling, it is cut into pieces. The finished negative electrode with a size of 125mm×42mm.

Battery assembly: the above-mentioned nickel positive electrode and hydrogen storage negative electrode are sandwiched by a sulfonated diaphragm made of PP material, wound into a multi-turn core by a winding machine and put into an AA-shaped steel case, and injected with a mass concentration of 30% KOH and The LiOH electrolyte with a mass concentration of 2% is finally sealed to make an AA1700 nickel-hydrogen battery.

Example 3

Production of positive electrode: (1) Mix 100 parts of spherical nickel hydroxide, 2 g of cobaltous oxide and 4 g of T255 nickel powder to make active material mixture; (2) Mix 5 g of calcium metaborate and 5 g of hydroxypropyl methylcellulose (3) Add the active material mixture prepared in step (1) to the aqueous solution in step (2), and add 2g of polytetrafluoroethylene emulsion Mix evenly to make a slurry; (4) Prepare a positive electrode product with a length and width of 90mm×42mm through processes such as pulp drawing, drying, cutting, powder cleaning, and electrode ear welding.

Preparation of the negative electrode: The hydrogen storage alloy powder is rolled onto the copper grid of the negative electrode substrate using the nickel-metal hydride battery dry negative electrode process, and a layer of polytetrafluoroethylene emulsion is soaked on the surface. After drying and rolling, it is cut into pieces. The finished negative electrode with a size of 125mm×42mm.

Battery assembly: the above-mentioned nickel positive electrode and hydrogen storage negative electrode are sandwiched by a sulfonated diaphragm made of PP material, wound into a multi-turn core by a winding machine and put into an AA-shaped steel case, and injected with a mass concentration of 30% KOH and The LiOH electrolyte with a mass concentration of 2% is finally sealed to make an AA1700 nickel-hydrogen battery.

Example 4

The preparation of the negative electrode of the control group 1 is the same as that of the above-mentioned examples. The difference in the preparation of the positive electrode is that no calcium metaborate or calcium borate is added. The other formulations are the same as the preparation method, and the preparation method of the nickel-hydrogen battery is also the same as the above-mentioned embodiment.

Example 5

The preparation of the negative electrode of the control group 2 is the same as the above-mentioned specific embodiment. The difference in the preparation of the positive electrode is that calcium metaborate or calcium borate is not added, but 1.0 g of calcium fluoride is added. The other formula is the same as the preparation method. The preparation of the nickel-hydrogen battery The method is also the same as the above-mentioned embodiment.

Example 6

The negative electrode preparation of the control group 3 is the same as the above-mentioned specific embodiment. The difference in the preparation of the positive electrode is that calcium metaborate or calcium borate is not added, but 1.0 g of calcium hydroxide is added. The other formulas are the same as the preparation method. The method is also the same as the above-mentioned embodiment.

Comparison of the distribution of calcium ions between the positive electrode prepared in Example 1 and the positive electrode prepared in Example 6:

In order to verify the distribution of calcium ions in the positive electrode, the EDX calcium ion distribution of the nickel-based battery positive electrode prepared in Example 1 and the nickel-based battery positive electrode prepared in Example 6 was compared, as shown in Figure 1, using the The positive electrode calcium ions are evenly distributed in the positive electrode, but the positive electrode calcium ions that use insoluble calcium salts are unevenly distributed. It is fully demonstrated by comparison that the simple method of using soluble calcium salts can easily solve the problem of uneven distribution of insoluble calcium salts in the positive electrode.

The performance comparison of the battery made by the specific embodiment and the battery made by the control group:

Battery high temperature performance test:

The nickel-hydrogen battery prepared in Example 1 and the nickel-hydrogen battery prepared in the control group were charged at 1800mA for 1.2 hours at 25°C and 70°C respectively, then the battery was left for 20 minutes, and then discharged at 0.2C until the voltage was 1.0V, and the battery was measured. capacity, the test results are shown in Table 1.

Table 1 Battery high temperature performance test

Battery cycle performance test:

The nickel-hydrogen battery prepared in Example 1 and the nickel-hydrogen battery prepared in the control group were respectively subjected to 1C charge and discharge test at ambient temperature of 25°C and 70°C. The test was terminated, and the test results are shown in Table 2.

Table 2 Battery cycle performance test

It can be seen from the above test results that the nickel-hydrogen battery with positive electrode prepared by the present invention can effectively improve the high-temperature discharge capacity and cycle life of the battery. Compared with Examples 5 and 6, the internal resistance of the nickel-hydrogen battery prepared in Example 1 of the present invention is significantly lower, which is mainly due to the uniform distribution of calcium ions inside the positive electrode and the introduction of beneficial anions. In addition, the implementation of the present invention Compared with Examples 5 and 6, the Ni-MH batteries prepared in Examples 2 and 3 also have excellent high-temperature performance and cycle performance.

The above embodiments describe the basic principles, main features and advantages of the present invention. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments, and that described in the above-mentioned embodiments and the specification only illustrates the principle of the present invention, and the present invention also has various aspects without departing from the scope of the principle of the present invention. Changes and improvements, these changes and improvements all fall within the protection scope of the present invention.

Claims (1)

1. a preparation method for nickel radical battery positive pole, is characterized in that comprising the following steps: the conductive agent of the nickel hydroxide of 100 weight portions and 0.5-10 weight portion mixes and obtains semifinal blend by (1); (2) the soluble calcium salt calcium metaborate of the hydrophilic agglomerant of 0.5-5 weight portion and 0.01-5 weight portion or line borate are mixed, be dissolved in the deionized water of 10-30 weight portion; (3) semifinal blend that step (1) is obtained is joined in the solution of step (2) gained, under the condition stirred, add the hydrophobic binder of 0.1-2 weight portion, through fully stirring the slurry preparing good fluidity; (4) slurry prepared by step (3) is coated on plus plate current-collecting body through pasting or slurry technique, through drying, compacting, be cut into the nickel radical battery positive pole of required size, conductive agent described in step (1) is cobalt protoxide or T255 nickel powder or the mixture of the two, hydrophilic agglomerant described in step (2) is sodium carboxymethylcellulose or hydroxypropyl methylcellulose, hydrophobic binder described in step (3) is ptfe emulsion, and the plus plate current-collecting body described in step (4) is Foamed Nickel, fiber nickel or punched nickel-plated steel band.