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A high-voltage lithium cobaltate positive electrode material with core-shell structure and preparation method thereof

A positive electrode material and a core-shell structure technology, which is applied to a high-voltage lithium cobalt oxide positive electrode material with a core-shell structure and the field of preparation thereof, can solve the problems of low mass percentage, aggravated electrolyte decomposition, and excessively thick coating layer, etc. The method is simple, the technical difficulty is reduced, and the effect of uniform thick layer coating

Active Publication Date: 2021-08-27
中科深蓝汇泽新能源(青岛)有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The problem faced by high-voltage lithium cobalt oxide is: on the one hand, high working voltage reduces the bulk phase structure stability of lithium cobalt oxide; on the other hand, high working voltage increases the interface reaction between lithium cobalt oxide and electrolyte, which reduces The stability of the surface structure of lithium cobalt oxide is impaired, and the decomposition of the electrolyte is intensified due to the increase of the oxidation state of cobalt ions, which ultimately makes it difficult for high-voltage lithium cobalt oxide batteries to simultaneously achieve high energy density, cycle life, and safety.
[0005] It is worth noting that the conductivity of coating materials is generally poor, and it is difficult to have high electronic and ionic conductivity at the same time, so the thickness of coating materials is usually required to be controlled at the nanometer level (Chinese invention patent: 201310069290.0), and The mass percentage of the total mass of the material is as low as possible
This not only increases the technical difficulty of uniform coating, but also easily causes the problems of local exposure and over-thickness of the coating layer on the surface of lithium cobalt oxide particles, which is not conducive to protecting the surface of lithium cobalt oxide particles and increases the cost of lithium cobalt oxide batteries. interface impedance

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  • A high-voltage lithium cobaltate positive electrode material with core-shell structure and preparation method thereof
  • A high-voltage lithium cobaltate positive electrode material with core-shell structure and preparation method thereof

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Embodiment 1

[0045] A core-shell structure lithium cobalt oxide cathode material, wherein the core material is lithium cobalt oxide, the shell material is a positive gradient material, and the average composition of the shell material is: LiCo 0.95 al 0.05 o 2 . The thickness of the shell material is 50nm, and the mass percentage of the shell material to the total weight of the lithium cobalt oxide is 0.5%.

[0046] The preparation method of the present embodiment comprises the following steps:

[0047] (1) Use battery-grade cobalt sulfate and aluminum sulfate as cobalt and aluminum sources respectively, dissolve them in deionized water, and control the molar ratio of Co:Al to 0.98:0.02 and 0.92:0.08 to prepare mixed salt solutions A and B respectively; Use battery-grade sodium hydroxide as raw material to configure 2mol / L alkaline solution; use ammonia water as raw material to control the molar ratio of metal ions:ammonia to 1:0.1 to configure 1mol / L ammonia solution.

[0048] (2) Put...

Embodiment 2

[0055] A core-shell structure lithium cobalt oxide cathode material, wherein the core material is lithium cobalt oxide, the shell material is a positive gradient material, and the average composition of the shell material is: LiCo 0.95 al 0.05 o 2 . The thickness of the shell material is 500 nm, and the mass percentage of the shell material to the total weight of the lithium cobalt oxide is 5%.

[0056] The preparation method of the present embodiment comprises the following steps:

[0057] (1) Use battery-grade cobalt sulfate and aluminum sulfate as cobalt and aluminum sources respectively, dissolve them in deionized water, and control the molar ratio of Co:Al to 0.98:0.02 and 0.92:0.08 to prepare mixed salt solutions A and B respectively; Use battery-grade sodium hydroxide as raw material to configure 2mol / L alkaline solution; use ammonia water as raw material to control the molar ratio of metal ions:ammonia to 1:0.1 to configure 1mol / L ammonia solution.

[0058] (2) Put...

Embodiment 3

[0063] A core-shell structure lithium cobalt oxide cathode material, wherein the core material is lithium cobalt oxide, the shell material is a positive gradient material, and the average composition of the shell material is: LiCo 0.95 al 0.05 o 2 . The thickness of the shell material is 1 μm, and the mass percentage of the shell material to the total weight of the lithium cobaltate is 20%.

[0064] The preparation method of the present embodiment comprises the following steps:

[0065](1) Use battery-grade cobalt sulfate and aluminum sulfate as cobalt and aluminum sources respectively, dissolve them in deionized water, and control the molar ratio of Co:Al to 0.98:0.02 and 0.92:0.08 to prepare mixed salt solutions A and B respectively; Use battery-grade sodium hydroxide as raw material to configure 2mol / L alkaline solution; use ammonia water as raw material to control the molar ratio of metal ions:ammonia to 1:0.1 to configure 1mol / L ammonia solution.

[0066] (2) Put a ce...

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Abstract

The invention discloses a high-voltage lithium cobalt oxide cathode material and a preparation method thereof. The disclosed high-voltage lithium cobalt oxide cathode material has a core-shell structure. In the method, a gradient material having the same crystal structure as the core material lithium cobalt oxide is used to coat the surface of the lithium cobalt oxide positive electrode material to obtain the lithium cobalt oxide positive electrode material with a core-shell structure. The gradient design of the coating material can make the coating material have the advantages of physical barrier, high conductivity, and electrochemical activity at the same time, and play the role of stabilizing the interface, rapidly conducting electrons / ions, and increasing the capacity. Compared with the commonly used coating modification method for lithium cobalt oxide positive electrode materials, the lithium cobalt oxide positive electrode materials provided by the present invention can achieve micron-scale thick layer coating, improve the uniformity of coating, reduce technical difficulty, and have higher Safety performance, energy density and cycle life.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a high-voltage lithium cobaltate cathode material with a core-shell structure and a preparation method thereof. Background technique [0002] At present, high-voltage lithium cobaltate (charging cut-off voltage greater than 4.45V) is an important cathode material for lithium-ion batteries that is of common concern to the scientific and technological circles. The problem faced by high-voltage lithium cobalt oxide is: on the one hand, high working voltage reduces the bulk phase structure stability of lithium cobalt oxide; on the other hand, high working voltage increases the interface reaction between lithium cobalt oxide and electrolyte, which reduces The stability of the surface structure of lithium cobalt oxide is compromised, and the decomposition of the electrolyte is intensified due to the increase of the oxidation state of cobalt ions, which ultimat...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/485H01M4/525H01M4/58H01M10/0525
CPCH01M4/366H01M4/485H01M4/525H01M4/5825H01M10/0525Y02E60/10
Inventor 崔光磊马君王龙龙虞鑫润姜丰孙兴伟徐红霞
Owner 中科深蓝汇泽新能源(青岛)有限责任公司