Composite cathode material, preparation method and lithium ion battery

A technology for compounding positive electrode materials and positive electrode materials, applied in the field of battery materials, can solve the problems of poor thermal stability of positive electrode materials, decreased capacity retention rate, uneven distribution of PTC, etc., achieves good thermal stability, improves thermal stability, and avoids side reactions. Effect

Active Publication Date: 2018-11-16
SOUNDON NEW ENERGY TECH CO LTD
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AI Technical Summary

Problems solved by technology

[0004] The main defect of the ternary cathode material is poor thermal stability under high temperature conditions. Specifically, at high temperature, the cathode material is prone to side reactions with the electrolyte, resulting in the dissolution of oxygen and metal ions in the material, and fundamental damage to the structure. The thermal stability of the material is poor, while the battery shows a rapid decline in the capacity retention rate
[0005] At present, the method of improving the thermal stability of positive electrode materials is mainly to mix PTC materials with positive electrode materials, conductive agents, binders, etc. during the homogenization process. This method will lead to uneven distribution of PTC on the surface of positive electrode materials. As a result, the battery resistance is too large, the battery is overheated locally, and the battery heat is out of control, resulting in potential safety hazards.

Method used

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  • Composite cathode material, preparation method and lithium ion battery
  • Composite cathode material, preparation method and lithium ion battery

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Experimental program
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Effect test

experiment approach 1

[0058] In order to further illustrate technical effect of the present invention, design experimental scheme one is:

[0059] A thin layer of MgAl was formed on the surface of the ternary cathode material by sol-gel method 2 o 4 Nanomaterials, ternary materials and MgAl 2 o 4 The mass ratio of MgAl is 80~100:0.5~5. During heat treatment, MgAl 2 o 4 It is possible to form a Li-Al-Co-O eutectic with the positive electrode material. With this structure, the corrosion of the electrolyte to the ternary material is reduced, the collapse of the material structure is avoided, and the cycle stability of the material is improved. At the same time MgAl 2 o 4 It has good high temperature resistance, can improve the high temperature stability of the material, and has a simple preparation method and is convenient for large-scale production. The synthesis steps are:

[0060] Step 1: Preparation of core-shell positive electrode material precursor: Weigh a certain amount of soluble Ni, ...

experiment approach 2

[0066] The second experimental design is:

[0067] Step 1: The nickel-cobalt-manganese ternary material precursor Ni 0.6 co 0.2 mn 0.2 (OH) 2 Mixed with lithium source, calcined to obtain ternary cathode material LiNi 0.6 co 0.2 mn 0.2 o 2 .

[0068] Step 2: MgAl with commercially purchased spinel structure 2 o 4 Nanomaterials and the ternary cathode material LiNi prepared in Step 1 0.6 co 0.2 mn 0.2 o 2 Mix in a ball mill.

[0069] Step 3: Calcining the mixture obtained in Step 2 to obtain a composite cathode material.

[0070] According to above-mentioned experimental design scheme, enumerate specific embodiment below, verify technical effect of the present invention:

Embodiment 1

[0072] In this example, MgAl is loaded with ternary material 2 o 4 As an example, the composite positive electrode material is described, the inner layer is LiNi 0.6 co 0.2 mn 0.2 o 2 , the outer layer is MgAl 2 o 4 . Among them LiNi 0.6 co 0.2 mn 0.2 o 2 with MgAl 2 o 4 The mass ratio of is 100:2, and its preparation method comprises the following steps:

[0073] Step 1: The commercialized layered high-nickel material Ni 0.6 co 0.2 mn 0.2 (OH) 2 Mixed with lithium acetate at a molar ratio of 1:1, mixed in a ball mill for 30 minutes, and calcined at 900°C for 6 hours to obtain the ternary cathode material LiNi 0.6 co 0.2 mn 0.2 o 2 .

[0074] Step 2: Taking magnesium salt and aluminum salt as starting raw materials, using water as solvent, configuring n(Mg 2+ ):n(Al 3 + ) = 1:2 mixed solution of metal ions, after mixing thoroughly, add an appropriate amount of citric acid as a complexing agent, and then heat at 70-100°C to form a complex sol.

[0075] ...

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Abstract

The invention relates to a composite cathode material, comprising a base cathode material and a magnesium aluminate material MgAl2O4 coating the surface of the base cathode material. Preferably, the base cathode material is a nickel-cobalt-manganese ternary cathode material LiNixCoyMnzO2 or a nickel-cobalt-aluminum ternary cathode material LiNixCoyAlzO2, wherein x+y+z=1, 0 (x, y, z (1. The invention also relates to a preparation method of the composite cathode material and a lithium ion battery. The MgAl2O4 on the surface of the cathode material can protect the cathode material in the inner layer, improve the thermal stability of the cathode material, and thus improve the cycle stability and safety of the battery.

Description

technical field [0001] The invention relates to the technical field of battery materials, in particular to a composite positive electrode material, a preparation method thereof and a lithium ion battery. Background technique [0002] Lithium-ion batteries have the characteristics of high energy density, long cycle life, no memory effect, and no pollution to the environment. They have been widely used in portable electronic devices and power vehicles. However, in actual production and application, due to the complexity of the environment, the capacity and safety of lithium-ion batteries are enough to become the key factors restricting the development of lithium-ion batteries. [0003] At present, the most widely used cathode materials for commercial lithium-ion batteries are lithium cobaltate, lithium manganate, lithium iron phosphate, layered nickel-cobalt-manganese ternary cathode material NCM, etc. Lithium cobaltate was the first to achieve industrial production, but due t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/525H01M4/505H01M4/485H01M4/62H01M10/0525
CPCH01M4/366H01M4/485H01M4/505H01M4/525H01M4/628H01M10/0525Y02E60/10
Inventor 靳岩娄忠良
Owner SOUNDON NEW ENERGY TECH CO LTD
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