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Boron nitride fiber-coated diaphragm for lithium ion battery and preparation method thereof

A boron nitride fiber and coating technology, which is applied in the field of boron nitride fiber-coated diaphragm and its preparation, can solve problems such as self-discharge electrolyte leakage, battery short circuit, mechanical instability, etc., and achieve improved thermal stability and thermal conductivity Good performance and mechanical stability

Active Publication Date: 2021-01-26
HUBEI UNIV OF EDUCATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the prior art, inorganic nanoparticles (such as SiO 2 、Al 2 o 3 , Al(OH) 3 , Mg(OH) 2 , Zeolite, ZrO 2 and TiO 2 ) coating the modified polyolefin battery separator to improve the thermal stability of the polyolefin battery separator, but the thermal stability improvement effect is not significant, and the battery separator modified by inorganic nanoparticles is brittle and has low flexibility (mechanical instability), Cracks will occur during battery assembly, and short circuits will occur immediately during battery operation; in the prior art, some alternatives to polyolefin battery separators have also been explored, such as non-woven separators. Although non-woven separators have good thermal stability, but these separators have a macroporous structure that is prone to internal short circuits, self-discharge and even electrolyte leakage
[0005] Therefore, other important parameters such as mechanical stability and cycle performance at high current rates and high temperatures cannot be well balanced with thermal stability in battery separators in the prior art.

Method used

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  • Boron nitride fiber-coated diaphragm for lithium ion battery and preparation method thereof
  • Boron nitride fiber-coated diaphragm for lithium ion battery and preparation method thereof
  • Boron nitride fiber-coated diaphragm for lithium ion battery and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0032] 1. 10 milliliters of boron trifluoride ether solution with a volume concentration of 45% is placed in a horizontal tube furnace, and ammonia gas is passed therein as a reaction gas, and the gas flow rate is 50 milliliters / minute at 1 degree Celsius. The heating rate per minute is raised to 300°C, and reacted at this temperature for 1 hour, and the product A obtained is a collapsed boron nitride fiber;

[0033] 2. After the product obtained in step 1 was cooled to room temperature, it was placed in 10 ml of alkaline aqueous solution with a pH value of 7.5, stirred for 0.5 hours, then heated to 65° C., and reacted at this temperature for 0.2 hours to obtain Mixing the solution, after the obtained mixed solution is cooled to room temperature, filtering the mixed solution to obtain a solid powder, and washing with deionized water until the surface of the solid powder is neutral to obtain product B;

[0034]3. Place the product B obtained in step 2 in an aqueous ethanol solu...

Embodiment 2

[0040] The operations of embodiment 2 and embodiment 1 are basically the same, except that in step 1, the consumption of boron trifluoride ether solution is 50 milliliters; the volume concentration of boron trifluoride ether solution is 30%; the obtained The decomposition temperature of the boron nitride fiber-coated diaphragm is close to 420°C, and the thermal conductivity reaches above 10W / m·K; the tensile strength reaches 220MPa at 300°C.

Embodiment 3

[0042] The operations of embodiment 3 and embodiment 1 are basically the same, except that in step 1, the consumption of boron trifluoride ether solution is 100 milliliters; the volume concentration of boron trifluoride ether solution is 20%; the obtained The decomposition temperature of the boron nitride fiber-coated diaphragm is close to 420°C, and the thermal conductivity reaches above 10W / m·K; the tensile strength reaches 220MPa at 300°C.

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Abstract

The invention discloses a boron nitride fiber-coated diaphragm for a lithium ion battery and a preparation method thereof. The boron nitride fiber-coated diaphragm is prepared by adopting a two-step method: step 1, firstly, preparing a boron nitride fiber material with high activity and a hexagonal structure by adopting a chemical activation method; and 2, coating the surface of the polyolefin diaphragm with the prepared boron nitride fiber by adopting a compression molding method to prepare the boron nitride fiber coated diaphragm. The chemical activation method adopted by the invention can overcome the defects that the existing synthesis process needs strong acid and strong alkali treatment and the technological process is complex. The method is low in preparation temperature, simple intechnological process, free of strong acid activation, small in pollution and suitable for large-scale industrial production. The boron nitride fiber-coated diaphragm prepared by adopting the method is high in thermal stability, high in thermal conductivity and good in mechanical stability, lithium ions can quickly pass through the diaphragm, the requirement of a high-power lithium ion battery canbe met, and the boron nitride fiber-coated diaphragm has a wide prospect in the field of high-power electronic packaging application.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a boron nitride fiber-coated separator for lithium-ion batteries and a preparation method thereof. Background technique [0002] As the world seeks to use energy resources more efficiently, improving battery technology is a high priority. Lithium-ion battery technology has high application requirements in some fields, such as electric vehicles, hybrid vehicles and power grids, and plays an important role in powering devices with high energy and power density. However, battery safety is a serious and challenging issue at present, especially the risk of battery fire and explosion has increased significantly, and the existing safety problems of lithium-ion batteries have risen to an extreme level, such as the battery fire and explosion of Samsung Note7, A battery fire in a Tesla electric car, and a battery problem with a Boeing 787 Dreamliner, among others. Therefore...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M50/449H01M50/411H01M50/44H01M50/403H01M10/0525
CPCH01M10/0525Y02E60/10
Inventor 李杰戴伟王聪燃王威东鲁楷方墁祺汪川惠祁红艳
Owner HUBEI UNIV OF EDUCATION