Coating diaphragm, preparation method and method for inhibiting lithium dendrites

A coating and separator technology, applied in the fields of inhibiting lithium dendrites, coating separators, and preparation, can solve the problems of unstable electrode and electrolyte interface, short circuit of lithium battery/lithium ion battery, low Coulomb efficiency, etc. Effects of Li dendrite growth, avoiding safety hazards and capacity reduction

Pending Publication Date: 2021-12-03
深圳市鼎泰祥新能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The growth of lithium dendrites will lead to the instability of the electrode-electrolyte interface during the cycle of lithium-ion batteries, destroying the generated solid electrolyte interface (SEI) film; and, the lithium dendrites will continue to consume the electrolyte during the growth process and lead to The irreversible deposition of metal lithium forms dead lithium, resulting in low coulombic efficiency; in addition, the formation of lithium dendrites can even pierce the separator, resulting in short-circuiting inside the lithium battery / lithium-ion battery, causing thermal runaway of the battery, causing combustion and explosion

Method used

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  • Coating diaphragm, preparation method and method for inhibiting lithium dendrites
  • Coating diaphragm, preparation method and method for inhibiting lithium dendrites
  • Coating diaphragm, preparation method and method for inhibiting lithium dendrites

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040]In this example, a polypropylene microporous membrane with a thickness of 20 μm and an average pore diameter of 20 nm is used as the base membrane. One surface of the base membrane is coated with polyvinylidene fluoride, and treated with a polarized electric field to form a piezoelectric polymer coating. Among them, the polypropylene microporous membrane was purchased from Celgard; the polyvinylidene fluoride (PVDF) was PVDF powder of MW ~ 534000 purchased from Sigma-Aldrich.

[0041] The concrete preparation method of the coating separator of this example is as follows:

[0042] Firstly, polyvinylidene fluoride was formulated into a coating liquid, and 10 g of polyvinylidene fluoride powder was mixed with 100 mL of DMF solvent, and stirred evenly to prepare a coating liquid.

[0043] Then, the polyvinylidene fluoride coating solution was coated on one surface of the base film by gravure coating, and the solvent was removed by drying; the coating amount was controlled to...

Embodiment 2

[0049] In this example, on the basis of Example 1, different base films, different piezoelectric polymer materials and different piezoelectric polymer coating thicknesses were tested, as detailed below:

[0050] Test 1: The polyvinylidene fluoride in Example 1 was replaced by a copolymer of vinylidene fluoride and chlorotrifluoroethylene in equal amounts, and the rest were the same as in Example 1;

[0051] Test 2: The polyvinylidene fluoride in Example 1 was replaced by a copolymer of vinylidene fluoride and trifluoroethylene in equal amounts, and the rest were the same as in Example 1;

[0052] Test 3: The polyvinylidene fluoride in Example 1 was replaced by a copolymer of chlorotrifluoroethylene and trifluoroethylene in equal amounts, and the rest were the same as in Example 1;

[0053] Test 4: The polyvinylidene fluoride in Example 1 was replaced by a copolymer of vinylidene fluoride, chlorotrifluoroethylene and trifluoroethylene in equal amounts, and the rest were the sam...

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Abstract

The invention discloses a coating diaphragm, a preparation method and a method for inhibiting lithium dendrites. The coating diaphragm comprises a base membrane and a piezoelectric polymer coating smeared on at least one surface of the base membrane. According to the coating diaphragm, the piezoelectric polymer coating is additionally arranged on the surface of the base diaphragm, when the coating diaphragm is used, the piezoelectric polymer coating of the coating diaphragm is in contact with a negative electrode, and when a trace amount of lithium dendrites are formed, the piezoelectric polymer coating of the coating diaphragm is extruded to form piezoelectric potential, so that the lithium element is prevented from continuously depositing at the point, and the purpose of inhibiting the growth of lithium dendrites is achieved. The coating diaphragm provided by the invention can inhibit the growth of lithium dendrites and avoid the problems of potential safety hazards, capacity reduction and the like caused by the mass growth of the lithium dendrites.

Description

technical field [0001] The present application relates to the field of battery diaphragms, in particular to a coating diaphragm, a preparation method and a method for inhibiting lithium dendrites. Background technique [0002] Lithium-ion batteries are widely used due to their high energy density, no memory effect, long cycle life and many other advantages. Generally, the basic components of a lithium-ion battery include a positive electrode sheet, a negative electrode sheet, an electrolyte, a separator, and a battery casing. Among them, the separator is called the "third pole" of the battery because of its key role in the lithium-ion battery. At the same time, in order to further increase the energy density of the battery, people are trying to develop a metal lithium battery that can be used stably. [0003] One of the common major challenges faced by lithium batteries / Li-ion batteries is the formation of lithium dendrites at the negative electrode. Li dendrite growth is...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M50/411H01M50/449H01M50/403H01M10/0525
CPCH01M10/0525Y02E60/10
Inventor 刘向春唐丽
Owner 深圳市鼎泰祥新能源科技有限公司
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