High-performance lithium-sulfur battery diaphragm and preparation method and application thereof

A lithium-sulfur battery, high-performance technology, used in lithium batteries, battery pack parts, non-aqueous electrolyte batteries, etc. Effect

Active Publication Date: 2020-02-28
安徽金力新能源有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The above-mentioned applications all inhibit the shuttling of lithium polysulfide by preparing a functional coating on the surface of the separator substrate, but the inhibitory effect is very limited. Therefore, how to further improve the inhibitory effect of lithium polysulfide shuttling in lithium-sulfur batteries is of great importance It is of great significance to ensure the performance of lithium-sulfur batteries

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  • High-performance lithium-sulfur battery diaphragm and preparation method and application thereof
  • High-performance lithium-sulfur battery diaphragm and preparation method and application thereof

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preparation example Construction

[0033] The preparation method of the high-performance lithium-sulfur battery diaphragm of the present invention comprises the following steps:

[0034] Step 1, extruding ultra-high molecular weight polyethylene (molecular weight 300,000 to 2,000,000), pore forming agent (paraffin oil, 50% to 70%), carbon nanotubes, conductive carbon black and / or graphene through twin-screw extrusion The sheet is obtained by melting, plasticizing, mixing and extruding, and then cooled by the casting roll to form a film with a thickness of 500-1500 μm. The temperature of the casting roll is 10-60 ° C. The obtained sheet is biaxially stretched ( Longitudinal and horizontal) systematic hole expansion and mechanical strength improvement to obtain a film with uniform thickness, the film is extracted by solvent, the paraffin oil is washed out, and then shaped by the shaping equipment, that is, the honeycomb porous diaphragm substrate is prepared. Among them, the magnification of longitudinal stretchi...

Embodiment 1

[0040] The preparation method of the high-performance lithium-sulfur battery diaphragm of this embodiment comprises the following steps:

[0041] Step 1, melting, plasticizing, mixing and extruding 20% ​​of ultra-high molecular weight polyethylene, 70% of pore-forming agent paraffin oil, 3% of carbon nanotubes and 7% of conductive carbon black through a twin-screw extruder to obtain a sheet, and then After being cooled by the casting roll, a film with a thickness of 500 μm is formed, and the temperature of the casting roll is 10°C; the obtained sheet is expanded by a biaxial stretching system and the mechanical strength is improved to obtain a film with uniform thickness. The film is extracted by solvent, and the paraffin wax The oil is washed out, and then shaped by the setting equipment to prepare a honeycomb porous diaphragm matrix. Among them, the magnification of longitudinal stretching is 5 times, and the stretching temperature is 90°C; the magnification of transverse st...

Embodiment 2

[0045] The preparation method of the high-performance lithium-sulfur battery diaphragm of this embodiment comprises the following steps:

[0046] Step 1. Melt, plasticize, mix and extrude 40% ultra-high molecular weight polyethylene, 50% pore-forming agent paraffin oil, 5% carbon nanotubes and 5% graphene through a twin-screw extruder to obtain a sheet, and then pass through The casting roll is cooled to form a film with a thickness of 1000 μm, and the temperature of the casting roll is 25°C; the obtained sheet is expanded through a biaxial stretching system and the mechanical strength is improved to obtain a film with uniform thickness. The film is extracted by solvent, and the paraffin oil Washing out, and then passing through the setting equipment to set the shape, the honeycomb-shaped porous diaphragm matrix is ​​prepared. Among them, the magnification of longitudinal stretching is 7 times, and the stretching temperature is 95°C; the magnification of transverse stretching ...

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Abstract

The invention discloses a high-performance lithium-sulfur battery diaphragm and a preparation method and application thereof, and belongs to the technical field of battery diaphragms. The high-performance lithium-sulfur battery diaphragm comprises a porous diaphragm matrix, and the porous diaphragm matrix is prepared from the following raw materials in percentage by mass: 20-40% of polyethylene, 0.5-10% of carbon nanotubes and 0.5-10% of conductive carbon black and/or graphene. The preparation process of the diaphragm comprises the following steps: blending and modifying polyethylene, carbon nanotubes and conductive carbon black and/or graphene through an extruder, and carrying out two-way stretching and extraction to prepare a honeycomb-shaped porous diaphragm matrix; and coating or compounding the surface of the porous diaphragm matrix with an inorganic nano ceramic layer to obtain the high-performance lithium-sulfur battery diaphragm. By adopting the technical scheme provided by theinvention, the shuttle effect of lithium polysulfide of the lithium-sulfur battery can be inhibited, and the use performance of the lithium-sulfur battery can be improved.

Description

technical field [0001] The invention belongs to the technical field of battery diaphragms, and more specifically relates to a high-performance lithium-sulfur battery diaphragm and its preparation method and application. Background technique [0002] Energy crisis and environmental issues are the two major challenges facing human society today, so adjusting the energy structure and developing clean and renewable new energy has become an urgent need in today's society. Among all electrochemical energy storage systems, lithium secondary batteries have been widely studied and applied due to their advantages of high voltage, high specific capacity, long cycle life, and no environmental pollution. Elemental sulfur has a very high theoretical capacity and energy density, and at the same time, sulfur has a series of advantages such as non-toxicity, environmental friendliness, wide source of raw materials, and low cost. Therefore, lithium-sulfur batteries are predicted to be the nex...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/052
CPCH01M10/052H01M50/431H01M50/446H01M50/403H01M50/449Y02E60/10
Inventor 邓豪晋沛沛王娟张杰庞冲
Owner 安徽金力新能源有限公司
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