Coating diaphragm with high flame retardance and lithium dendrite growth inhibition function and preparation method of coating diaphragm

A technology of lithium dendrites and high flame retardancy, which is applied in the field of coating separators with high flame retardancy and inhibition of lithium dendrite growth and its preparation, can solve problems such as thermal runaway, short-circuiting of lithium-ion batteries, and degradation of battery cycle performance. Achieve good high temperature resistance and thermal conductivity, improve the ability to resist open flames, and improve the effect of battery safety

Inactive Publication Date: 2022-04-19
JIANGSU HORIZON NEW ENERGY TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

During the charging and discharging process of the battery, gaps are prone to appear between the diaphragm and the pole piece, resulting in a decrease in the battery cycle performance, and even lithium deposition in the gap, resulting in a short circuit in the battery; the diaphragm is mostly made of polyolefin material, which has a very low melting point. When there is thermal runaway, the diaphragm is prone to membrane rupture, which will lead to more serious thermal runaway, which will cause the battery to burn or even explode
At present, the market mainly provides high-temperature-resistant ceramic coating separators, which can delay the closure of the diaphragm to 150°C, but the closure temperature of 150°C cannot completely avoid the short circuit of the lithium battery at high temperature and the spontaneous combustion caused by it. Therefore, it is necessary to further improve the diaphragm. Heat resistance, reduce the risk of diaphragm rupture and improve battery safety
In addition, the formation of lithium dendrites will also pierce the separator and cause short-circuiting inside the lithium-ion battery, causing thermal runaway of the battery to cause combustion and explosion, which has a great impact on the safety and stability of lithium batteries.

Method used

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  • Coating diaphragm with high flame retardance and lithium dendrite growth inhibition function and preparation method of coating diaphragm
  • Coating diaphragm with high flame retardance and lithium dendrite growth inhibition function and preparation method of coating diaphragm
  • Coating diaphragm with high flame retardance and lithium dendrite growth inhibition function and preparation method of coating diaphragm

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preparation example Construction

[0032] Fabrication of BNNS Nanosheets: Using Ultrasonic-Assisted Liquid-Phase Exfoliation.

[0033] (1) The hexagonal boron nitride powder of 1.5g is dispersed in the mixed solvent of 300mL isopropanol and ultrapure water (the volume ratio of isopropanol and ultrapure water is 1:1), in the process, the ultrasonic cleaning machine The power is 180W, and the ultrasonic stripping time is 12h; after stripping, the obtained dispersion is centrifuged at 2000rpm for 20min to remove the remaining unstripped hexagonal boron nitride, and finally the supernatant after centrifugation is vacuum filtered and stored at 100°C After drying for 10 h, BNNS nanosheets were obtained.

[0034](2) Preparation of functionalized BNNS nanosheets: using sol-gel method.

[0035] First, an appropriate amount of APTES (3% of the mass of BNNS) was added to 100 mL of absolute ethanol, and stirred at 60° C. for 30 min to fully hydrolyze APTES. Then 2g of BNNS was dispersed into the solution, stirred at 80°C...

Embodiment 1

[0037] Step 1: First, stir 26Kg of ultrapure water, 0.24Kg of dispersant and 8Kg of functionalized BNNS nanosheets to obtain a BNNS dispersion, and then add 16Kg of Mg(OH) 2 Stir the powder to mix the solution evenly, then add 3.2Kg of thickener and mix evenly; grind the obtained slurry to D90<2.0μm through a sand mill, and finally add 3.5Kg of binder, 0.2Kg of moistening The wet agent is stirred evenly to coat the slurry.

[0038] Step 2: Coating slurry on both sides of the base film: using the micro-gravure roll coating process, the prepared coating slurry is coated on both sides of the 9 μm polyethylene base film step by step through the coating machine, and the coating thickness is The thickness is 3 μm, and the separator A is obtained after being baked in an oven at 70°C.

[0039] Step 3: Using methanol and tris buffer solution with pH=8.5 as co-solvents (methanol:buffer solution=1:1), immerse the diaphragm A in 0.01mol polydopamine solution for surface modification. Af...

Embodiment 2

[0041] Step 1: First, stir 20Kg of ultrapure water, 0.15Kg of dispersant and 5Kg of functionalized BNNS nanosheets to obtain a BNNS dispersion, and then add 10Kg of Mg(OH) 2 Stir the powder to mix the solution evenly, then add 1Kg of thickener and mix evenly; grind the obtained slurry to D90<2.0μm through a sand mill, and finally add 1Kg of binder and 0.15Kg of wetting agent and mix evenly Slurry must be applied.

[0042] Step 2: Immerse the base film in an aqueous solution of 1.8 mg / L tannic acid for 10 minutes, then transfer to an aqueous solution of 0.1 mmol / L sodium periodate and immerse for 5 minutes; cycle 2 times; coat on both sides Slurry: Using the micro-gravure roller coating process, the prepared coating slurry is coated on both sides of a 9 μm polyethylene-based film step by step through a coating machine, with a coating thickness of 3 μm, and baked in a 70°C oven Then wind up the separator A.

[0043] Step 3: Using methanol and tris buffer solution with pH=8.5 a...

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Abstract

The invention discloses a coating diaphragm with high flame retardance and lithium dendrite growth inhibition and a preparation method thereof.The preparation method comprises the following steps that 1, functionalized BNNS nanosheets and Mg (OH) 2 powder are stirred and dispersed in water and homogenized, and coating slurry is obtained; 2, coating a base membrane with the coating slurry, and drying; a diaphragm A is obtained; step 3; dipping the diaphragm A in a polydopamine solution, washing and drying; and obtaining the coated diaphragm. (1) through the synergistic effect between the functionalized BNNS nanosheet and Mg (OH) 2, the ion transmission rate, the flame retardant property and the heat resistance of the coated diaphragm are remarkably improved; (2) through modification of dopamine and tannic acid, the hydrophilicity of a coating layer is increased, the ion conduction rate and the ion conductivity are greatly improved, and the growth of lithium dendrites in the battery is effectively inhibited; and meanwhile, the adhesion between the functionalized BNNS nanosheet and the Mg (OH) 2 and the base membrane is improved.

Description

technical field [0001] The invention relates to the technical field of battery separators, in particular to a coated separator with high flame retardancy and inhibition of lithium dendrite growth and a preparation method thereof. Background technique [0002] With the rapid growth of society's demand for energy and the depletion of traditional non-renewable energy sources, the development of the new energy industry has attracted worldwide attention. Among them, secondary batteries with high energy density represented by lithium-ion batteries are widely used as key devices for energy storage and conversion. As the energy of the battery is getting higher and the number of cycles is increasing, it also puts forward higher requirements for the safety performance of the battery, and the separator, as one of the main components of the lithium-ion battery, plays an important role in the safety performance of the battery . [0003] The separator is located between the positive and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M50/403H01M50/446H01M50/449H01M10/613H01M10/653H01M10/654A62C3/16B82Y30/00B82Y40/00
CPCH01M50/403H01M50/449H01M50/446H01M10/613H01M10/653H01M10/654A62C3/16B82Y30/00B82Y40/00
Inventor 刘美林张立斌陈朝晖
Owner JIANGSU HORIZON NEW ENERGY TECH CO LTD
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