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Lithium ion secondary battery and preparation method thereof

A secondary battery and lithium ion technology, applied in secondary battery, electrolyte battery manufacturing, battery electrodes, etc., can solve the problems of poor battery cycle performance, re-agglomeration of particles, large volume effect, etc., to improve cycle performance and avoid re- Agglomeration, slow down the effect of pulverization

Active Publication Date: 2012-06-27
DONGFANG ELECTRIC CORP LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to overcome the defects of the prior art that the silicon-based negative electrode of the lithium-ion battery has a large volume effect and is easy to pulverize during the charging and discharging process, thereby resulting in poor cycle performance of the battery, and provides a lithium-ion battery containing a gel coating Lithium-ion secondary batteries made of silicon-based negative electrodes can slow down the pulverization of silicon-based negative electrode active material particles during charge and discharge, and can avoid re-agglomeration of particles

Method used

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  • Lithium ion secondary battery and preparation method thereof

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Effect test

Embodiment 1

[0033] Gel coat solution: In a flowing nitrogen atmosphere, polyhexafluoropropylene-vinylidene fluoride (HFP-PVDF, in which HFP content is 10%), dimethyl carbonate (DMC) containing 1.0mol / L lithium hexafluorophosphate / Ethylene carbonate (EC) was mixed at a mass ratio of 1:84:15 and stirred at 75°C until dissolved.

[0034] Positive electrode composition and positive electrode: lithium cobaltate (LiCO 2 ) as the positive electrode active material, prepare the positive electrode slurry according to the methods known to those skilled in the art; coat the slurry on both sides of a 16 micron aluminum foil; vacuum bake at 90°C for 3.5h (vacuum degree is - 90kPa), rolling, and slicing; the energy density of the obtained positive electrode is 1.0mAh / cm 2 .

[0035] Negative electrode composition and negative electrode: 10% by weight of nano-silicon (D50=100nm) and 90% by weight of artificial graphite are mixed to form the negative electrode active material, and the negative electro...

Embodiment 2

[0044] Gel coat solution: In a flowing nitrogen atmosphere, polyhexafluoropropylene-vinylidene fluoride (HFP-PVDF, in which HFP content is 10%), dimethyl carbonate (DMC) containing 2.0mol / L lithium hexafluorophosphate (DMC) / Ethylene carbonate (EC) was mixed at a mass ratio of 1:84:15 and stirred at 75°C until dissolved.

[0045] Positive electrode composition and positive electrode: lithium cobaltate (LiCO 2 ) as the positive electrode active material, prepare the positive electrode slurry according to the methods known to those skilled in the art; coat the slurry on both sides of a 16 micron aluminum foil; vacuum bake at 90°C for 3.5h (vacuum degree is - 90kPa), rolling, and slicing; the energy density of the obtained positive electrode is 1.0mAh / cm 2 .

[0046] Negative electrode composition and negative electrode: 10% by weight of nano-silicon (D50=100nm) and 90% by weight of artificial graphite are mixed to form the negative electrode active material, and the negative e...

Embodiment 3

[0055] Gel coating solution: In a flowing nitrogen atmosphere, polyhexafluoropropylene-vinylidene fluoride (HFP-PVDF, in which HFP content is 10%), dimethyl carbonate (DMC) containing 0.5mol / L lithium hexafluorophosphate / Ethylene carbonate (EC) was mixed at a mass ratio of 1:84:15 and stirred at 75°C until dissolved.

[0056] Positive electrode composition and positive electrode: lithium cobaltate (LiCO 2 ) as the positive electrode active material, prepare the positive electrode slurry according to the methods known to those skilled in the art; coat the slurry on both sides of a 16 micron aluminum foil; vacuum bake at 90°C for 3.5h (vacuum degree is - 90kPa), rolling, and slicing; the energy density of the obtained positive electrode is 1.0mAh / cm 2 .

[0057] Negative electrode composition and negative electrode: 10% by weight of nano-silicon (D50=100nm) and 90% by weight of artificial graphite are mixed to form the negative electrode active material, and the negative elec...

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Abstract

The invention relates to a lithium ion secondary battery and a preparation method thereof. The cathode of the battery is a lithium ion battery silicon-based cathode containing a gel coating and comprises a current collector, a silicon-based cathode material loaded on the current collector and the gel coating which is coated on the surface of the silicon-based cathode material through heat treatment after coating, wherein the gel coating comprises a polymer matrix material, a non-aqueous solvent, a toughening agent and a lithium electrolyte salt dissolved in the non-aqueous solvent and has a thickness of 5 to 50 mu m, preferably, 10 to 20 mu m. According to the invention, the cathode of the lithium ion secondary battery is coated with the gel coating, and the gel coating comprises a polymer matrix with high elasticity and high viscosity and electrolyte containing a lithium salt, is coated on the surface of the silicon-based cathode and forms a semi-solid gel layer on the surface of the cathode and in pores through heat treatment, thereby alleviating pulverization of particles of active substances in the silicon-based cathode during the processes of charging and discharging and avoiding re-agglomeration of the particles.

Description

technical field [0001] The invention relates to a battery and a preparation method thereof. More specifically, the invention relates to a lithium ion secondary battery and a preparation method thereof, belonging to the field of lithium ion secondary batteries. Background technique [0002] With the wide application and rapid development of various portable electronic devices and electric vehicles, the demand and performance requirements for chemical power sources have increased dramatically. Compared with other chemical power sources, lithium-ion batteries are successfully and widely used in the field of terminal mobile electronic devices due to their advantages such as long life and high power characteristics. At present, the lithium transition metal oxide / graphite system is mostly used in commercial lithium batteries. Due to the low theoretical lithium storage capacity of electrodes in this system (such as graphite, 372mAh / g), it can no longer meet people's demand for high...

Claims

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Application Information

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IPC IPC(8): H01M4/62H01M4/134H01M10/0525H01M10/058
CPCY02E60/122Y02E60/10Y02P70/50
Inventor 阮晓莉谢皎王睿胡蕴成王荣贵
Owner DONGFANG ELECTRIC CORP LTD
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