Anode active substance and its preparing method and anode and battery

A positive electrode active material and oxide technology, which is applied in the field of positive electrode active material and its preparation of alkaline secondary batteries, can solve the problem of affecting battery cycle performance, charge and discharge efficiency performance, inability to overcome battery self-discharge rate, and affecting cobalt coating Layer utilization and other issues to achieve the effect of overcoming the micro-short circuit of the battery, preventing the loss of cobalt on the positive active material, and avoiding the loss of cobalt

Inactive Publication Date: 2008-04-02
BYD CO LTD
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AI Technical Summary

Problems solved by technology

Positive divalent cobalt is easily dissolved in the electrolyte, resulting in the loss of cobalt in the cobalt oxide and / or hydroxide coating layer of the positive electrode active material of the battery, which affects the effect of the cobalt coating layer on improving the utilization rate of nickel hydroxide particles
Positive divalent cobalt dissolved in the electrolyte, accumulated as Co 3 o 4 It is easy to cause micro-short circuit between the positive electrode and the negative electrode of the battery, and also increase the self-discharge rate of the battery, affecting the performance of the battery cycle performance, charge and discharge efficiency, etc.
[0007] In summary, since the cobalt oxide and / or hydroxide coating layer of the existing positive electrode active material is exposed to the electrolyte, the cobalt oxide and / or hydroxide in the coating layer will react with the negative electrode for hydrogen evolution The free hydrogen reacts, so it cannot overcome the disadvantage of high self-discharge rate of the battery caused by the hydrogen evolution reaction

Method used

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  • Anode active substance and its preparing method and anode and battery

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preparation example Construction

[0028] The present invention also provides a method for preparing the above-mentioned positive electrode active material, wherein the method comprises wetting the nickel hydroxide particles 1 coated with cobalt oxide and / or hydroxide coating layer 2 with an aqueous solution of metal salt, Drying, contacting the obtained nickel hydroxide particles 1 coated with cobalt oxide and / or hydroxide coating 2 with a metal salt on the surface, and washing with an alkaline solution, wherein the aqueous solution of the metal salt is selected from One or more of the aqueous solutions of soluble salts of magnesium, barium, zinc, calcium, titanium, aluminum, tantalum, manganese, yttrium, chromium, cadmium, strontium and lanthanide rare earth elements. The soluble metal salt is one or more of metal sulfate, metal halide and metal nitrate. Considering the problem of environmental pollution, preferably the aqueous solution of the metal salt is selected from one or more of the aqueous solutions o...

Embodiment 1

[0062] This example illustrates the positive electrode active material provided by the present invention and its preparation method.

[0063] (1) Coating cobalt hydroxide layer for nickel hydroxide particles

[0064] Put 100 grams of commercially available nickel hydroxide particles (Japan, Tanaka spherical nickel hydroxide) into 400 milliliters of deionized water, and slowly add 100 milliliters of 0.7 mol / liter CoSO 4 solution and 100 milliliters of 1.4 mol / liter sodium hydroxide aqueous solution, the pH of the resulting mixture is maintained at 11.4 to 11.6 during the addition of the aforementioned two solutions, producing nickel hydroxide particles deposited with cobalt hydroxide. The particles were separated by filtration, washed with 5 times the weight of deionized water three times, and dried under vacuum at 100°C. After passing through a 200-mesh sieve, spherical nickel hydroxide particles coated with a cobalt hydroxide layer with an average diameter of 10 microns and ...

Embodiment 2

[0077] This example illustrates the positive electrode active material provided by the present invention and its preparation method.

[0078] Nickel hydroxide particles coated with a cobalt hydroxide layer (containing CoOOH) were prepared according to the method described in Example 1, the difference being that, based on the weight of the nickel hydroxide particles, in terms of cobalt element, the hydrogen The content of cobalt hydroxide in the cobalt oxide coating layer was 3% by weight, and the average valence state of cobalt in the coating layer was 3.

[0079] Mix 1000 milliliters of 0.036 mol / L manganese chloride aqueous solution with 100 grams of nickel hydroxide particles coated with a cobalt hydroxide coating layer, and the manganese chloride aqueous solution contains 0.018 mole of disodium edetate. Under stirring conditions at 40°C, slowly add about 40 milliliters of 2 mol / liter sodium hydroxide aqueous solution, so that the resulting liquid maintains a pH of 10, and ...

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Abstract

The invention discloses an anode active matter, which comprises a nickel hydroxide particle (1) and an oxide of cobalt and/or hydroxid packing layer (2) which is coated on the surface of the nickel hydroxide particle, wherein, the anode active matter is covered with a second packing layer (3) on the surface of the oxide of cobalt and/or hydroxid packing layer (2). The second packing layer (3) is the oxide of metal and/or hydroxid which is selected from one or more from magnesium, barium, zinc, calcium, titanium, aluminum, tantalum, manganese, yttrium, chromium, cadmium, strontium and oxide of lanthanides lanthanon and/or hydroxid. The anode active matter of the invention is covered with the second packing layer on the surface of oxide of cobalt and/or hydroxid packing layer for protecting the oxide of cobalt and/or hydroxid from reducing by hydrogen generated by hydrogen separating reaction. At the same time, the oxygen separation overpotential is improved, thereby greatly reducing self discharging rate of battery and improving circulation performance and charging and discharging efficiency.

Description

technical field [0001] The present invention relates to a positive electrode active material and a preparation method thereof, as well as a positive electrode comprising the positive electrode active material and a battery comprising the positive electrode, in particular to a positive electrode active material of an alkaline secondary battery and a preparation method thereof, and comprises A positive electrode of the positive electrode active material and a battery including the positive electrode. Background technique [0002] Alkaline secondary batteries, such as nickel-cadmium secondary batteries, nickel-zinc secondary batteries or nickel-hydrogen secondary batteries, are widely used in the fields of electronics and communications, and their application fields are expanding day by day. Alkaline secondary batteries generally include an electrode group and an alkaline electrolyte sealed in a battery case. The electrode group includes a positive electrode, a negative electr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/52H01M4/48B22F1/02H01M4/24H01M10/24
CPCY02E60/124Y02E60/10
Inventor 周文会
Owner BYD CO LTD
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