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Coated diaphragm and preparation method thereof

A coating and diaphragm technology, applied in the direction of separators/films/diaphragms/spacers, electrical components, circuits, etc., can solve the problem of affecting the weight and electrochemical performance of batteries, hindering the migration channel and rate of lithium ions, and increasing the battery life. The difficulty of core injection and other issues can be improved to improve the rate performance and cycle performance, reduce the risk of deformation, and reduce the effect of adverse effects

Pending Publication Date: 2022-04-15
SHANGHAI ENERGY NEW MATERIALS TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the design of the multi-layer coating layer increases the thickness of the diaphragm, which affects the weight and electrochemical performance of the battery cell; and the coating process is cumbersome and complicated, and the product production efficiency is low
In addition, the polymer coating layer has a low absorption rate of the electrolyte, which increases the difficulty of liquid injection during the production of the battery cell; at the same time, the coating layer will affect the air permeability of the diaphragm, hinder the migration channel and rate of lithium ions, and have a greater impact on the internal resistance of the diaphragm. Electrochemical properties such as cell rate and cycle need to be sacrificed

Method used

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  • Coated diaphragm and preparation method thereof
  • Coated diaphragm and preparation method thereof
  • Coated diaphragm and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0034] Example 1 This example provides a coated separator, which contains porous PMMA microspheres with a particle size D50 of 3.8 μm, a porosity of 35%, and an average pore size of 150 nm.

[0035] Concrete preparation method is as follows:

[0036] Step S1, preparing porous PMMA microspheres;

[0037] Preparation 500ml mass fraction is 2% polyvinyl alcohol (PVA) aqueous solution, in PVA solution, add 19.5g MMA monomer, 0.1g benzoyl peroxide and 10.5g n-octanol, stir with 65r / min at 70 ℃ React for 24 hours; after the polymerization is completed, fully wash with water, filter and dry; repeatedly soak the dried product in n-butanol, wash and filter three times, and fully dry to finally obtain a particle size D50 of 3.8 μm, a porosity of 35%, and an average pore size of Porous PMMA microspheres with a size of 150 nm.

[0038] Step S2, preparation of aqueous slurry;

[0039] Add 48g of aluminum oxide and 1.2g of sodium carboxymethylcellulose dispersant to 133.3g of deionized w...

Embodiment 2

[0042] Example 2 This example provides a coated separator, which contains porous PMMA microspheres with a particle diameter D50 of 2.7 μm, a porosity of 23%, and an average pore diameter of 85 nm.

[0043] Concrete preparation method is as follows:

[0044] Step S1, preparing porous PMMA microspheres;

[0045] Configure 500ml of 2% polyvinyl alcohol (PVA) aqueous solution, add 22.5g of MMA monomer, 0.1g of benzoyl peroxide and 7.5g of n-octanol to the PVA solution, and stir the reaction at 100r / min at 70°C for 24 hours After the polymerization is completed, it is fully washed with water, filtered and dried; the dried product is repeatedly soaked, washed and filtered three times with n-butanol, and fully dried to finally obtain a particle size D50 of 2.7 μm, a porosity of 23%, and a pore size of 85 nm. Porous PMMA microspheres.

[0046] Step S2, preparation of aqueous slurry;

[0047]Add 48g of aluminum oxide and 1.2g of sodium carboxymethylcellulose dispersant to 133.3g of ...

Embodiment 3

[0050] Example 3 This example provides a coated separator, which contains porous PMMA microspheres with a particle diameter D50 of 1.2 μm, a porosity of 11%, and an average pore diameter of 35 nm.

[0051] Concrete preparation method is as follows:

[0052] Step S1, preparing porous PMMA microspheres;

[0053] Configure 500ml of 2% polyvinyl alcohol (PVA) aqueous solution, add 26.4g of MMA monomer, 0.1g of benzoyl peroxide and 3.6g of n-octanol to the PVA solution, and stir the reaction at 135r / min at 70°C for 24 hours After the polymerization is completed, it is fully washed with water, filtered and dried; the dried product is repeatedly soaked, washed and filtered three times with n-butanol, and fully dried to finally obtain a particle size D50 of 1.2 μm, a porosity of 11%, and an average pore size of 40nm porous PMMA microspheres.

[0054] Step S2, preparation of aqueous slurry;

[0055] Add 48g of aluminum oxide and 1.2g of sodium carboxymethylcellulose dispersant to 13...

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Abstract

The invention provides a lithium battery diaphragm, and particularly relates to a coated diaphragm. The coated diaphragm at least comprises a base membrane and a coating layer coated on at least one side of the base membrane, the coating layer at least comprises porous PMMA microspheres, ceramic particles, a thickening agent, a water-based adhesive and a wetting agent, the particle size D50 of the porous PMMA microspheres is 1.0-4.0 [mu] m, the porosity is 10-40%, and the average pore size is 30-150 nm. According to the coating layer, the thermal shrinkage performance of the diaphragm can be improved, the porous PMMA microspheres in the coating layer provide better circulation and liquid retention channels for electrolyte, the electrolyte wettability of the diaphragm is improved, rapid liquid injection can be achieved, meanwhile, the adverse effect of the polymer coating layer on the air permeability can be reduced, the ionic conductivity of the polymer coating layer is improved, and the service life of the diaphragm is prolonged. The rate capability and the cycle performance of the battery cell are improved. In addition, the coating layer can improve the bonding performance of the diaphragm and the pole piece, reduce the deformation risk of the battery cell and improve the safety performance of the battery cell.

Description

technical field [0001] The invention belongs to the field of battery diaphragm preparation, and in particular relates to a high-viscosity coated diaphragm for lithium batteries. Background technique [0002] With the rapid development of lithium battery applications, traditional polyolefin separators are difficult to meet market demand. As an important part of the battery, the improvement of the performance of the separator has a crucial impact on improving the electrochemical performance and safety performance of the lithium battery. [0003] In the existing reports, the thermal stability is mainly improved by coating the surface of the polyolefin separator with an inorganic coating layer, or a polymer coating layer is used to improve its bonding performance with the positive and negative electrodes, thereby improving the cycle life of the battery cell. and safety performance. Invention patent CN109103397A discloses a method for preparing a ceramic material-coated diaphra...

Claims

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Application Information

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IPC IPC(8): H01M50/40H01M50/403H01M50/449
CPCH01M50/40H01M50/403H01M50/449Y02E60/10
Inventor 庄志马芸周广盖廖晨博李文强冶成良程跃
Owner SHANGHAI ENERGY NEW MATERIALS TECH CO LTD
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