Composite anode active material and preparation method thereof, anode and battery

A technology for positive active materials and active materials, which is applied in the field of composite positive active materials and their preparation, positive electrodes and batteries, can solve the problems of loss of electrochemical activity, insufficient preparation process, and non-uniform dispersion, etc., to achieve lithium supplementation Uniform distribution, excellent lithium supplementation effect, good effect of lithium deintercalation performance

Active Publication Date: 2019-06-11
HUIZHOU BYD BATTERY
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  • Abstract
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AI Technical Summary

Problems solved by technology

[0003] These methods all have many disadvantages. On the one hand, because metal lithium is too active, the entire operating environment has extremely strict requirements for moisture, so that the lithium-intercalated negative electrode cannot be exposed to the air for a long time. Cloth, drying, slitting, rolling, rolling and other operations are not enough to complete in a short time
The organic solvent used when spraying or dropping organic lithium is a flammable and explosive chemical reagent, and there are potential safety hazards in the operation process.
[0004] Other methods of lithium supplements that do not use lithium powder are generally to physically blend the lithium supplement and the positive electrode material, including direct physical mixing, diaphragm, and surface coating of the positive and negative electrodes. Among them, in order to disperse uniformly, the lithium supplement particles used The problem that this will cause is: the small particles after del

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  • Composite anode active material and preparation method thereof, anode and battery
  • Composite anode active material and preparation method thereof, anode and battery
  • Composite anode active material and preparation method thereof, anode and battery

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preparation example Construction

[0034] A second aspect of the present invention provides a method for preparing a composite positive electrode active material, the method comprising:

[0035](1) In the first aqueous solvent, in the presence of a complexing agent and a precipitating agent, the water-soluble salt forming the positive electrode active material other than the lithium salt is subjected to coprecipitation treatment to obtain a core precursor;

[0036] (2) The core precursor is subjected to surface hydroxylation treatment;

[0037] (3) In the second aqueous solvent, heat-treat the product of the surface hydroxylation treatment, silicon source and water-soluble salt containing M element;

[0038] (4) performing solid-liquid separation on the heat-treated product, drying and roasting the obtained solid phase to obtain a composite positive electrode active material with a core-shell structure;

[0039] Wherein, water-soluble lithium salt is introduced during the heat treatment of step (3) and / or in t...

Embodiment 1

[0088] This example is used to illustrate the composite cathode active material of the present invention and its preparation method.

[0089] (1) 50mmol of nickel nitrate and 50mmol of cobalt nitrate are dissolved in 100g of water, then 5g of ammonia water (concentration is 10% by weight) is added and sodium hydroxide is added to adjust the pH to 11, to carry out co-precipitation reaction at 30°C for 24h, and filter to obtain Core Prebody ( figure 1 As can be seen from the SEM image shown, the particle size of the core precursor is about 10 μm);

[0090] (2) immerse the core precursor in 10% by weight hydrogen peroxide at 25° C. for 30 minutes, and then obtain the core precursor treated with surface hydroxylation;

[0091] (3) Add 10 g of the surface hydroxylated core precursor to a mixed solvent of 100 g of ethanol and water (the weight ratio of methanol and water is 2:1), and reflux for 30 min, and then dropwise add 7.5 g of orthosilicic acid Ethanol solution of ethyl este...

Embodiment 2

[0095] This example is used to illustrate the composite cathode active material of the present invention and its preparation method.

[0096] According to the method described in embodiment 1, the difference is:

[0097] In step (3), the core precursor of this surface hydroxylation treatment of 10g, the ethanol solution of 7.5g orthosilicate ethyl (concentration of orthosilicate is 30% by weight), the aqueous solution of 195g ferrous nitrate (nitrite nitrate Iron concentration is 1% by weight) and lithium nitrate aqueous solution (lithium nitrate concentration is 10% by weight) of 50g joins in the airtight autoclave, and the mixed solvent of the ethanol and water that adds 100g (the weight ratio of methyl alcohol and water is 2 : 1), then stirred and reacted at 150°C for 5h, filtered and dried to obtain a solid phase;

[0098] In step (4), the amount of lithium nitrate aqueous solution is 40g;

[0099] Finally, a composite positive electrode active material is obtained. It ...

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Abstract

The invention relates to the field of anode materials, in particular to a composite anode active material and a preparation method thereof, an anode and a battery. The composite anode active materialhas a core-shell structure, wherein a core contains an anode active material, a shell layer contains a silicate material of a pmn2<1> crystal structure, the silicate material contains Li elements andM elements, and the M elements are divalent metal elements. According to the composite anode active material with the core-shell structure, lithium-supplementing agents are distributed on the shell layer, the anode active material is formed in the core, so that the lithium-supplementing agents are distributed more uniformly and combined more tightly, lithium disembedding performance is better, andthe composite anode active material has an excellent lithium-supplementing effect and can obtain better circulation performance.

Description

technical field [0001] The invention relates to the field of positive electrode materials, in particular to a composite positive electrode active material, a preparation method thereof, a positive electrode and a battery. Background technique [0002] In order to reduce the decrease in battery capacity due to the irreversible capacity of the battery during the first charge and discharge process, there is a method of adding dry powder in the prior art, specifically adding lithium powder to the surface of the negative plate to make up for this defect. However, since lithium powder is easy to float in the air, it will cause greater safety hazards to operators. For this reason, it also includes spraying or dripping the organic lithium solution on the surface of the negative electrode sheet in an inert atmosphere, so that the lithium ions in the organic lithium solution are reduced to metal lithium and embedded in the negative electrode sheet, and then the negative electrode shee...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M10/05
CPCY02E60/10
Inventor 胡栋杰
Owner HUIZHOU BYD BATTERY
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