Composite coated diaphragm for high-nickel ternary lithium-ion battery and preparation method thereof

A lithium-ion battery and separator technology, applied in the field of composite coating separator and its preparation, can solve the problems of decreased material/electrolyte interface stability, increase of battery internal pressure and temperature, affecting material cycle stability, etc. Large-scale application, inhibition of decomposition, and the effect of facilitating the promotion and application of equipment

Inactive Publication Date: 2018-02-16
桑顿新能源科技(长沙)有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the main way to increase the energy density of lithium-ion batteries is to use high-nickel ternary positive electrodes (NCM / NCA, the molar fraction of nickel ≥ 0.6) with silicon-carbon negative electrode materials. As the content increases, the stability of the material will gradually decrease, especially the stability of the material / electrolyte interface will decrease accordingly, leading to the occurrence of side reactions and affecting the cycle stability of the material
In addition, due to the rich layered structure of the high-nickel ternary cathode material, its charge-discharge rate performance is poor, and it has obvious shortcomings in high-rate charge-discharge, and under the condition of overcharge, it is easy to cause polarization to cause the oxidative decomposition of the electrolyte. A large amount of heat is released, which increases the internal pressure and temperature of the battery, posing a safety hazard
These defects of high-nickel ternary lithium-ion batteries limit its development and application to a certain extent. In order to solve these problems, people usually add various additives to the electrolyte to improve the interface stability of the material and the rate charge and discharge performance of the battery. And use a ceramic separator to improve the safety performance of the battery, but the overall improvement effect is limited

Method used

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  • Composite coated diaphragm for high-nickel ternary lithium-ion battery and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Add nanometer α-alumina powder and LA133 with a mass ratio of 80:20 to a certain amount of water for stirring and dispersion to obtain a mixed slurry with a solid content of 61%, and then coat the slurry on the PP / PE composite diaphragm base On one side of the material, the coating thickness was measured after drying and rolling. Then take artificial graphite containing lithiated sulfonic acid groups, carbon nanotubes, and polyvinylidene fluoride with a mass ratio of 90:5:5, and add them to a certain amount of N-methylpyrrolidone to stir and mix the slurry to obtain a solid content of 52%. The mixed slurry is uniformly coated on the other side of the diaphragm, dried and rolled to obtain the desired composite coated diaphragm.

Embodiment 2

[0027] Add nano α-alumina powder and gelatin with a mass ratio of 75:25 to a certain amount of water for stirring and dispersion to obtain a mixed slurry with a solid content of 64%, and then coat the slurry on one side of the PP diaphragm substrate On, coating thickness was measured after drying and rolling. Add activated carbon containing lithiated sulfonic acid groups, Super P, and polytetrafluoroethylene with a mass ratio of 82:8:10 to a certain amount of N-methylpyrrolidone and stir to make a slurry to obtain a positive electrode with a solid content of 58%. Slurry, the slurry is evenly coated on the other side of the separator, dried and rolled to obtain the desired composite coated separator.

Embodiment 3

[0029] Add nano α-alumina powder and sodium alginate with a mass ratio of 90:10 to a certain amount of water for stirring and dispersion to obtain a mixed slurry with a solid content of 59%, and then coat the slurry on the PE diaphragm substrate On one side, the coating thickness was measured after drying and rolling. Then take the microporous carbon containing lithiated sulfonic acid groups, Ketjen black, and sodium carboxymethyl cellulose with a mass ratio of 95:3:2 and add them to a certain amount of water for stirring and slurrying to obtain a solid content of 65%. Positive electrode slurry, the slurry is evenly coated on the other side of the diaphragm, dried and rolled to obtain the required composite coating diaphragm.

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Abstract

The invention discloses a composite coated diaphragm for a high-nickel ternary lithium-ion battery and a preparation method thereof. According to the composite coated diaphragm provided by the invention, a ceramic coating at one side of a negative electrode contains inorganic oxide so that the ceramic coating has relatively good heat-resisting property and mechanical strength and the thermal safety stability of the high-nickel ternary lithium-ion battery can be effectively improved; a sulfonic acid group on a carbon coating at one side of a positive electrode can be used for inhibiting the decomposition of electrolyte to a certain extent so that the interface stability between a material and the electrolyte is enhanced, the circulating performance of the battery is improved and the rate performance of the battery is effectively improved; the two types of coatings are complementary to each other due to respective excellent performance, so that the circulating performance, the rate performance and the safety performance of the high-nickel ternary lithium-ion battery are improved and large-scale application of a system is promoted; the composite coated diaphragm for the high-nickel ternary lithium-ion battery is high in practicability and equipment is easy to popularize and apply.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and in particular relates to a composite coated separator for high-nickel ternary lithium ion batteries and a preparation method thereof. Background technique [0002] With the continuous development of new energy vehicles in my country, the requirements for battery energy density are getting higher and higher. As the current mainstream battery system, lithium-ion batteries have been widely used in power batteries due to their advantages such as high energy density, good cycle performance, and no memory effect. However, the energy density of lithium-ion batteries in my country can only reach 260Wh / kg, which is still a long way from the 2020 target of 300Wh / kg. In order to vigorously develop new energy vehicles, it is imperative to increase the energy density of lithium-ion batteries. [0003] At present, the main way to increase the energy density of lithium-ion batteries is to use high-nic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M50/403H01M50/431H01M50/434H01M50/457H01M50/489
CPCH01M50/403H01M50/446Y02E60/10
Inventor 程兴邢伟伟李小兵陈小平胡泽林文一波
Owner 桑顿新能源科技(长沙)有限公司
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