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Lithium battery composite diaphragm and preparation method thereof

A composite diaphragm and lithium battery technology, which is applied in secondary batteries, battery pack components, secondary battery repair/maintenance, etc., can solve the problems of poor wettability of ceramic coating diaphragms, and achieve ultra-high electrolyte absorption Liquid rate and retention rate, improved transferability, and good thermal stability

Pending Publication Date: 2021-06-22
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In view of this, the present invention aims to propose a lithium-ion battery diaphragm and a preparation method thereof to solve the problems of poor wettability and poor wettability of existing ceramic coating diaphragms

Method used

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  • Lithium battery composite diaphragm and preparation method thereof
  • Lithium battery composite diaphragm and preparation method thereof
  • Lithium battery composite diaphragm and preparation method thereof

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preparation example Construction

[0032] combine Figure 4 As shown, the embodiment of the present invention provides a preparation method of a lithium battery composite diaphragm, comprising steps:

[0033] S1. Disperse the pretreated montmorillonite in a solvent, stir and disperse evenly, and obtain a montmorillonite dispersion;

[0034] S2. Take the upper turbid liquid of the montmorillonite dispersion, place it in a centrifuge tube for centrifugation, and obtain montmorillonite nanosheets, place the montmorillonite nanosheets in an alkaline solution for infiltration, and then ultrasonically treat them in an ice bath to obtain Montmorillonite emulsion, finally solid-liquid separation, drying to obtain montmorillonite powder;

[0035] S3, uniformly mixing the montmorillonite powder and the oil-based binder to form an oil-based coating slurry;

[0036] S4. Coating the oil-based coating slurry on the surface of the lithium battery separator, and drying to obtain a lithium battery composite separator.

[003...

Embodiment 1

[0054] This embodiment provides a preparation method of a lithium battery composite diaphragm, and the specific steps are as follows:

[0055] (1) Place 5.00 g of 800 mesh montmorillonite powder after ball milling and 100 ml (102.60 g) of NMP (purity > 99.9%) in a solvent, at a speed of 2000 rpm, a temperature of 25 ° C in a constant temperature stirrer, Stir for 5 minutes, and then perform ultrasonic treatment to obtain a montmorillonite dispersion;

[0056] (2) Get the upper turbid liquid of the montmorillonite dispersion, centrifuge to obtain montmorillonite nanosheets with uniform size, put them into the alkaline solution and infiltrate, so that the weak alkali solution is fully embedded between the montmorillonite layers after infiltration, Then carry out ultrasonic treatment in an ice bath, separate solid and liquid, and dry to obtain montmorillonite powder;

[0057] (3) Dissolve 2.00g polyvinylidene fluoride (PVDF) in 100ml NMP solvent, configure 20.00mg / ml PVDF binder...

Embodiment 2

[0065] This embodiment provides a method for preparing a lithium battery composite diaphragm, which differs from Embodiment 1 in that:

[0066] In step (3), dissolve in 100ml NMP solvent with 2.00g polytetrafluoroethylene (PTFE), configure the PTFE binding agent of 20.00mg / ml; Take 5ml PTFE binding agent with pipette gun, add dropwise to 1.00g In the montmorillonite powder, mix evenly to form an oil-based coating slurry;

[0067] Other steps and parameters are the same as in Example 1.

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Abstract

The invention provides a lithium battery composite diaphragm and a preparation method thereof, and the preparation method comprises the following steps: S1, dispersing pretreated montmorillonite in a solvent, and uniformly stirring and dispersing to obtain a montmorillonite dispersion liquid; S2, taking upper turbid liquid of the montmorillonite dispersion liquid, putting the upper turbid liquid into a centrifugal tube for centrifugal treatment to obtain montmorillonite nanosheets, putting the montmorillonite nanosheets into an alkaline solution for infiltration, then performing ice-bath ultrasonic treatment to prepare montmorillonite emulsion, and finally performing solid-liquid separation and drying to obtain montmorillonite powder; S3, uniformly mixing the montmorillonite powder with an oil-based binder to form an oil-based coating slurry; and S4, coating the surface of the lithium battery diaphragm with the oil coating slurry, and drying to obtain the lithium battery composite diaphragm. According to the lithium battery composite diaphragm provided by the invention, rapid transmission of lithium ions on the diaphragm is facilitated, the cycle performance and the ionic conductivity of the diaphragm are improved, the preparation process is simple and feasible, the product purity is high, the preparation cost is low, and the lithium battery composite diaphragm is suitable for large-scale industrial production.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a lithium battery composite diaphragm and a preparation method thereof. Background technique [0002] With the rapid development of the application of lithium-ion batteries, the lithium battery diaphragm, one of the key materials of the lithium battery structure, has gradually become a research hotspot in the field of lithium batteries. The ions in the liquid pass freely between the positive and negative electrodes. The performance of the separator determines the interface structure and internal resistance of the battery, which directly affects the capacity, cycle and safety performance of the battery. Traditional commercial separator materials mainly include polyolefin separator materials, such as polyethylene (PE) and polypropylene (PP), but the mechanical strength and relatively low melting point of polyolefin separators limit the improvement of the safety performan...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M50/403H01M50/431H01M50/449H01M10/0525H01M10/42B82Y30/00B82Y40/00
CPCH01M10/0525H01M10/4235B82Y30/00B82Y40/00Y02E60/10
Inventor 徐林费凡麦立强张建永邓家辉
Owner WUHAN UNIV OF TECH
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