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Composite separator membrane, preparation method thereof, and application thereof in lithium ion batteries

A composite separator, lithium ion technology, applied in secondary batteries, battery pack components, circuits, etc., can solve the problems of high-speed charging/discharging performance damage, battery performance degradation, and no positive improvement, and achieve excellent Charge/discharge characteristics, improve battery safety, reduce the effect of short-circuit phenomenon

Inactive Publication Date: 2016-10-05
JIANGXI GANFENG BATTERY TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The use of separators with inorganic particles (such as alumina, zirconium oxides, titanium oxides, etc. non-lithium ion conductors) as fillers acts to prevent heat shrinkage and can improve the safety of the battery, but the battery tends to exhibit poor charging / discharge characteristics
Especially when the battery is charged and discharged at a relatively large current, the performance of the battery is significantly reduced in a low-temperature environment. This is because the porous membrane is densely filled with inorganic particles. Therefore, the inorganic filler particles not only have no positive effect on the lithium-ion battery. The effect of improving, and the non-lithium ion conductor oxide has the possibility of blocking the rapid migration of lithium ions, so that the high-speed charging / discharging characteristics of lithium-ion batteries are impaired, and it cannot be charged / discharged in a low temperature environment
[0005] The publication numbers are CN103296235A and CN103236511A patent applications, both of which use inorganic oxide non-lithium ion conductors as the diaphragm material. The increase in the thickness of the diaphragm in the above two patents increases the resistance of the composite diaphragm, while the dense inorganic oxide non-ion conductor It will reduce the volume ratio of the pores in the porous surface of the separator, reduce the ion diffusion coefficient and ion conductivity, reduce the actual capacity of the battery, and impair the high-speed charge / discharge performance

Method used

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  • Composite separator membrane, preparation method thereof, and application thereof in lithium ion batteries
  • Composite separator membrane, preparation method thereof, and application thereof in lithium ion batteries
  • Composite separator membrane, preparation method thereof, and application thereof in lithium ion batteries

Examples

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preparation example Construction

[0075] This application also provides a method for preparing a composite diaphragm, including the following steps:

[0076] After mixing the binder, the organic solvent and the sulfide conductor material, they are dispersed to obtain a suspension;

[0077] The suspension is coated on the surface of the diaphragm and dried to obtain a composite diaphragm.

[0078] The sulfide conductor material is preferably a lithium ion conductor as shown in formula (I), formula (II), and formula (III):

[0079] Li 4-x (M 1-y M′ y ) z S 4 (Ⅰ);

[0080] M is selected from one of Si and Ge, and M'is selected from one of P, Al, Zn, and Ga;

[0081] -1≤x≤2, 0≤y≤1, 0.9≤z≤2.

[0082] Li 10+x M 1+x P 2-x S 12 (Ⅱ);

[0083] M is selected from one or more of the elements of the third, fourth or fifth main group;

[0084] -1≤x≤1.

[0085] xLi 2 S·(100-x-z)M y S n ·ZR (Ⅲ);

[0086] 0 3+ , P 3+ , P 5+ , Si 4+ Or Ge 4+ , R is LiI, Li 3 PO 4 , Li 4 SiO 4 , P 2 O 5 , GeS 2 Or P 2 S 3 .

[0087] In the process of preparing...

Embodiment 1

[0102] In a glove box filled with argon, the average particle size is 0.3 micron Li 3.25 P 0.95 S 4 It is a ceramic layer, polyvinylidene fluoride (PVDF) is the binder, N-methylpyrrolidone (NMP) is the solvent, the mass ratio of binder, organic solvent and conductor material is 1:20:10, and the three are mixed Then prepare the slurry. AFA-II automatic film coating machine of Shanghai Pushen Chemical Machinery Co., Ltd. was used for single-sided coating on the PP-PE-PP three-layer composite membrane (celgard 2300), and dried in a vacuum oven at 60°C for 10 hours to obtain a ceramic composite Diaphragm. Figure 4 This is a scanning electron micrograph of the sulfide solid electrolyte material of this example. The thickness of the diaphragm before coating is 25 microns, and the thickness of the diaphragm after coating and drying is 27 microns. The calculated coating thickness is 2 microns. The comparison of coating thickness, liquid absorption and conductivity data is shown in Ta...

Embodiment 2

[0105] In a glove box filled with argon, the average particle size is 0.3 micron Li 10 GeP 2 S 12 It is a ceramic layer, polyvinylidene fluoride (PVDF) is the binder, N-methylpyrrolidone (NMP) is the solvent, the mass ratio of binder, organic solvent and conductor material is 1:20:10, and the three are mixed Then prepare the slurry. Use the AFA-II automatic film coating machine of Shanghai Pushen Chemical Machinery Co., Ltd. to apply single-sided coating on the PP-PE-PP three-layer composite membrane (celgard 2300), and then transfer to a vacuum oven at 60°C for 10 hours. A ceramic composite diaphragm is obtained. The comparison of coating thickness, liquid absorption and conductivity is shown in Table 1, and the comparison of heat shrinkage data is shown in Table 1. Picture 9 .

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Abstract

The invention provides a composite separator membrane which includes a separator membrane and a conductor material coating which is composited on the surface of the separator membrane. The conductor material coating includes a sulfide conductor material. The conductor material coating on the surface of the separator membrane contains the sulfide conductor material, so that during charging and discharging of a lithium ion battery, the separator membrane can supply a path for transmitting lithium ions, so that damage on the charging and discharging performance of the lithium ion battery is avoided due to existence of the path in the sulfide conductor material even the surface of the separator membrane is coated with the coating and the porosity of the surface of the separator membrane is reduced, and meanwhile, a long cycle life is achieved. The invention also provides a preparation method of the composite separator membrane and an application thereof in the lithium ion batteries.

Description

Technical field [0001] The present invention relates to the technical field of lithium ion batteries, and in particular to a composite diaphragm, a preparation method thereof and its application in a lithium ion battery. Background technique [0002] The application field of lithium-ion batteries is still based on liquid electrolyte lithium-ion batteries, and its main components include positive electrode, negative electrode, electrolyte and separator. Among them, the diaphragm is the most critical inner layer component and core material of lithium-ion batteries. The key properties of the battery, such as capacity, safety, cycle capacity, and rapid charge and discharge capabilities, are directly related to the diaphragm. Further optimization of the diaphragm material can simultaneously solve the problem of lithium ion. Battery specific energy and safety are two issues. The traditional method uses a liquid electrolyte combined with a simple polymer separator, but lithium ion batt...

Claims

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Application Information

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IPC IPC(8): H01M2/14H01M2/16H01M10/0525H01M50/403H01M50/431
CPCY02E60/10
Inventor 许晓雄朱骏陈晓添高超
Owner JIANGXI GANFENG BATTERY TECH