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Polyimide-coated lithium ion battery positive electrode active material, preparation method and application

A positive electrode active material and lithium-ion battery technology, which is applied to battery electrodes, secondary batteries, circuits, etc., can solve the problems of concentrated thermal effect inside the battery, crushing and cracking of active materials, and unfavorable industrial production, so as to increase the bonding effect and maintain Stability, the effect of improving thermal stability

Pending Publication Date: 2022-08-05
HANGZHOU INST OF ADVANCED MATERIAL BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the rate performance and cycle performance of the material after coating by this method are improved, the preparation method is relatively complicated, which is not conducive to industrial production.
Commonly used inorganic coatings such as Al 2 o 3 , ZrO 2 etc. can improve the performance of the material to a certain extent, but after a period of time, the inorganic material generates internal and external stress, which leads to stress concentration during the cycle, cracks inside the active material, and structural damage, which accelerates the crushing and cracking of the active material, resulting in Attenuation of battery capacity and concentration of thermal effects inside the battery

Method used

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  • Polyimide-coated lithium ion battery positive electrode active material, preparation method and application
  • Polyimide-coated lithium ion battery positive electrode active material, preparation method and application
  • Polyimide-coated lithium ion battery positive electrode active material, preparation method and application

Examples

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Effect test

Embodiment 1

[0044] Weigh out 6FDA 6.57g, ODA 1.47g, and TFDB 2.35g with a molar ratio of 10:5:5. Dissolve ODA and TFDB in 30ml of NMP solvent, stir mechanically, after ODA and TFDB are all dissolved in NMP, under ice-water bath conditions, add 6FDA to obtain a polyamic acid solution with a solid content of 25%. Dilute to a 10% solids solution. The positive active material lithium iron phosphate is placed in the above-mentioned 10% polyamic acid solution, mixed, centrifuged, suction filtered, and dried to prepare the positive active material coated with polyamic acid. For amination treatment, the heat treatment process is to heat up from room temperature to 300°C at a constant rate for 60min, and keep the temperature for 60min. Mix the surface-coated lithium iron phosphate, conductive carbon black, and PVDF solutions according to 80%, 10%, and 10% by mass, add NMP solvent to dissolve the mixture, and stir for 20 minutes to prepare a positive electrode slurry. The positive electrode slurr...

Embodiment 2

[0047] Weigh 6FDA 6.57g, ODA 1.47g, and TFDB 2.35g with a molar ratio of 10:5:5, dissolve all ODA and TFDB in 30ml of NMP solvent, stir mechanically, and after ODA and TFDB are all dissolved in NMP, take an ice-water bath Under the condition of , 6FDA is added step by step to obtain a polyamic acid solution with a solid content of 25%, and the polyamic acid solution is prepared into a solution with a solid content of 5%. The positive electrode active material lithium iron phosphate was placed in a 5% polyamic acid solution, mixed, centrifuged, filtered, and dried to prepare a polyamic acid-coated positive electrode active material. After grinding and sieving, high temperature thermal imide Chemical treatment, the heat treatment process is from room temperature to 300 °C for 60 min at a constant rate, and heat preservation for 60 min. Mix the surface-coated lithium iron phosphate, conductive carbon black, and PVDF solutions according to 80%, 10%, and 10% by mass, add NMP solven...

Embodiment 3

[0050] Weigh 6FDA 6.57g, ODA 1.47g, and TFDB 2.35g with a molar ratio of 10:5:5, dissolve all ODA and TFDB in 30ml of NMP solvent, stir mechanically, and after ODA and TFDB are all dissolved in NMP, take an ice-water bath Under the condition of , 6FDA is added step by step to obtain a polyamic acid solution with a solid content of 25%, and the polyamic acid solution is prepared into a solution with a solid content of 5%. The positive active material NCM523 was placed in a 5% polyamic acid solution, mixed, centrifuged, filtered, and dried to prepare a polyamic acid-coated positive active material. After grinding and sieving, high-temperature thermal imidization was performed. , the heat treatment process is to heat up from room temperature to 300°C at a constant rate for 60min, keep for 60min, mix conductive carbon black and PVDF solution according to the mass fraction of 80%, 10% and 10%, and add NMP solvent. The surface-coated NCM523 was dissolved in the mixture and stirred f...

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Abstract

The invention relates to a polyimide-coated lithium ion battery positive electrode active material as well as a preparation method and application thereof. Polyimide is used for carrying out surface coating modification on the lithium ion battery positive electrode active material. And dispersing the positive electrode active material in polyimide precursor polyamide acid, centrifuging, drying, grinding, screening and carrying out thermal imidization to obtain the polyimide coated and modified positive electrode active material of the lithium ion battery. The polyimide surface coating layer can restrain the volume expansion effect of the positive electrode in the charging and discharging process of the lithium ion battery, restrain the interface side reaction between the electrolyte and the positive electrode active material, maintain the stability of the crystal structure of the positive electrode active material, effectively promote the development of the positive electrode capacity and prolong the long cycle life of the battery.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a polyimide-coated positive electrode active material for lithium ion batteries and a preparation method and application thereof Background technique [0002] In order to meet the requirements of high-performance lithium-ion batteries in the application fields of rapidly developing electric vehicles, consumer electronics and large-scale energy storage power stations, the innovation of lithium-ion battery material system has become an important part of battery performance improvement. Among the four main materials of lithium-ion batteries, the cathode materials have gradually developed towards high energy density from lithium iron phosphate to lithium nickel cobalt oxide to lithium-rich and high-nickel materials. However, the improvement of the energy density of cathode materials has made the safety and life problems of batteries more and more prominent, such as poor thermal s...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/62H01M10/0525C08G73/10
CPCH01M4/366H01M4/628H01M10/0525C08G73/1067C08G73/1071C08G73/1064C08G73/1057C08G73/1039C08G73/1007Y02E60/10
Inventor 齐胜利王亚丽齐可心徐跃明田国峰武德珍
Owner HANGZHOU INST OF ADVANCED MATERIAL BEIJING UNIV OF CHEM TECH
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