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Positive electrode slurry and preparation method thereof and lithium-ion battery

A technology of positive electrode slurry and sizing material, which is applied in battery electrodes, secondary batteries, circuits, etc., can solve the problems of poor stability, poor cycle performance of lithium cobalt oxide, and easy damage to the structure of deep deintercalation lithium materials.

Active Publication Date: 2017-01-04
GREE ELECTRIC APPLIANCES INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, in practical applications, lithium cobalt oxide materials also have two problems: (1) due to the structure of deep deintercalation lithium materials is easily damaged
High voltage can extract more lithium ions from the crystal structure, increasing the capacity of the battery, but a large amount of lithium extraction will affect the cycle performance and safety performance of the battery due to structural damage
Especially under high-voltage charge-discharge conditions, the cycle performance of lithium cobalt oxide deteriorates, and the main reason for the rapid capacity decay is the phase transition of the material in the high delithiation state and the loss of oxygen in the lattice, resulting in structural instability; the reaction between the material and the electrolyte causes Caused by factors such as the dissolution of cobalt
[0006] At present, the cycle performance and stability of lithium cobalt oxide batteries are deteriorating and other defects have increasingly restricted lithium cobalt oxide materials. Overcoming the defects has become one of the focuses of many R&D manufacturers in the industry.

Method used

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  • Positive electrode slurry and preparation method thereof and lithium-ion battery
  • Positive electrode slurry and preparation method thereof and lithium-ion battery
  • Positive electrode slurry and preparation method thereof and lithium-ion battery

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preparation example Construction

[0072] The present invention also provides a method for preparing positive electrode slurry, comprising the following steps:

[0073] A) After the binder and the solvent are mixed by rotation and revolution, the rubber compound is obtained;

[0074] B) The conductive agent, nano-alumina and solvent are mixed by rotation and revolution for the second time, and then the rubber material and lithium cobaltate material prepared in the above steps are added for the third rotation and revolution, stirred and mixed to obtain the positive electrode slurry.

[0075] The selection and ratio of the raw materials in the present invention are consistent with the selection and ratio of the raw materials for the positive electrode slurry, unless otherwise specified, and will not be repeated here.

[0076] In the present invention, firstly, the binder and the solvent are stirred and mixed by rotation and revolution to obtain the glue material.

[0077] In the present invention, there is no sp...

Embodiment 1

[0133] According to the solid content (m 1 +m 2 +m 3 +m 4 ) / (m 1 +m 2 +m 3 +m 4 +m NMP )=70%, according to LCO: (SP+KS-6): PVDF: Nano Al 2 o 3 =(96.5:1.4:1.8:0.3) weighed, its LCO, SP+KS-6, PVDF, nano Al 2 o 3 The mass of each is denoted as m 1 、m 2 、m 3 、m 4 .

[0134] 1. Glue making

[0135] According to the content of PVDF in the rubber compound is 10% to make rubber

[0136] Consider process loss, weigh PVDF mass 1.2m 3 , the mass of NMP is required to be 10.8m 3 , see Table 3.

[0137] table 3

[0138]

[0139]

[0140] 2. Stirring

[0141] Adding method of conductive agent and other additives:

[0142] Take out 10% of the above rubber (containing PVDF:NMP=1:9), LCO, SP, KS-6, nano-Al 2 o 3 The mass of each is denoted as m 1 、m 2 、m 4 , weigh the NMP to be supplemented, and record the mass as m 5 , see Table 4.

[0143] Table 4

[0144]

[0145]

[0146] The slurry was prepared by the above process of Example 1, and a batch of lit...

Embodiment 2

[0150] According to the solid content (m 1 +m 2 +m 3 +m 4 ) / (m 1 +m 2 +m 3 +m 4 +m NMP )=70%, according to LCO:(SP+KS-6):PVDF:nano Al 2 o 3 =(96.5:1.7:1.8:0) weighed (i.e. do not add nanometer Al 2 o 3 ), its LCO, SP+KS-6, PVDF, nano Al 2 o 3 The mass of each is denoted as m 1 、m 2 、m 3 、m 4 . Stirring steps are consistent with Example 1.

[0151] According to Example 2: the maximum difference in the internal resistance of the prepared battery is within 3%, and the maximum difference in the first discharge specific capacity of the battery under 1C is 2.4mAh / g (about 1.45%), and the battery has shown good consistency, thus indicating The slurry obtained under this stirring scheme has good stability and uniformity.

[0152] In this way, the first average discharge capacity of the prepared battery at 1C is 166mAh / g (charging cut-off voltage 4.35V, discharge cut-off voltage 3V), and after 100 cycles, the capacity retention rate is 90.3%. The capacity of the mat...

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Abstract

The invention provides positive electrode slurry, which comprises the following raw materials in parts by weight: 93-97.5 parts of lithium cobalt oxide materials, 1.5-2.5 parts of conductive agents, 1.5-3 parts of binders and 0.1-0.5 part of a nano-aluminum oxide and a solvent. In a plurality of influence factors of the lithium-ion battery, first of all, nano Al2O3 is added to the positive electrode slurry from components and proportion of the positive electrode slurry, so that the positive electrode slurry can effectively play roles in heat insulation and insulation and the safety performance of the battery is improved. Furthermore, a lithium cobalt oxide and the nano Al2O3 form a solid solution and can stabilize lattices and the rate capability and the cycle performance of the battery are improved. Meanwhile, the nano Al2O3 coats the lithium cobalt oxide, so that the heat stability can be improved, the cycle ability and the overcharge resistance are improved, generation of oxygen and decomposition of LiPF6 are inhibited, contact of the lithium cobalt oxide and an electrolyte can be reduced and the capacity loss is reduced, so that the capacity is improved.

Description

technical field [0001] The invention relates to the technical field of lithium ion battery materials, and relates to a positive electrode slurry, a preparation method thereof, and a lithium ion battery, and in particular to a lithium cobaltate positive electrode slurry, a preparation method thereof, and a lithium ion battery. Background technique [0002] Lithium-ion batteries have the advantages of high working voltage, high specific energy, long cycle life, light weight, less white discharge, no memory effect and high cost performance, and have become rechargeable batteries in high-power electric vehicles, artificial satellites, aerospace and other fields. The main selection object of the power supply. Therefore, lithium-ion batteries and related materials have become a research hotspot for researchers. Cathode material is one of the key materials of lithium-ion batteries, which determines the performance of lithium-ion batteries. At present, the biggest bottleneck that ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/525H01M10/0525H01M4/62
CPCH01M4/525H01M4/62H01M10/0525Y02E60/10
Inventor 王文华钟宽陈阳李乾乾李影田静吉纯曾庆苑段科钟署亮王晋蒋世用
Owner GREE ELECTRIC APPLIANCES INC
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