Lithium-sulfur battery composite integrated diaphragm, preparation method and lithium-sulfur battery

A lithium-sulfur battery and separator technology, which is applied in the field of composite integrated separator and preparation of lithium-sulfur batteries, can solve the problems of deactivation of active materials, limited effectiveness, and reduced battery capacity, and achieves high flexibility, thermal stability, and structural retention. The effect of stable, high mechanical stability

Active Publication Date: 2022-06-03
CHINA UNIV OF PETROLEUM (EAST CHINA)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the effect of this electrostatic interaction is limited, and the sulfur species that have left the positive electrode cannot continue to participate in the electrochemical reaction on the insulating separator, resulting in the deactivation of the active material and the reduction of the battery capacity.

Method used

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  • Lithium-sulfur battery composite integrated diaphragm, preparation method and lithium-sulfur battery
  • Lithium-sulfur battery composite integrated diaphragm, preparation method and lithium-sulfur battery
  • Lithium-sulfur battery composite integrated diaphragm, preparation method and lithium-sulfur battery

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preparation example Construction

[0049] According to a first aspect of the present invention, a method for preparing a composite integrated separator for a lithium-sulfur battery is provided, comprising the following steps:

[0050] (a) providing polyamic acid spinning solution;

[0051] Electrospinning the polyamic acid spinning solution to obtain a polyamic acid fiber membrane;

[0052] (b) thermally imidizing the polyamic acid fiber film in air to obtain a polyimide fiber film;

[0053] (c) Using CO 2 The laser irradiates the surface of the polyimide fiber film to obtain a composite integrated separator for a lithium-sulfur battery.

[0054] Specifically, in step (a), the polyamic acid spinning solution is treated by electrospinning, which can ensure that the obtained polyamic acid fiber membrane has high flexibility and thermal stability, and ensures the subsequent CO 2 The underlying structure of the polyimide fiber membrane remains stable during laser processing.

[0055] In step (b), thermal imidiz...

Embodiment approach

[0061] As an optional embodiment of the present invention, the preparation method of polyamic acid spinning solution comprises the following steps:

[0062] The diamine, the dianhydride and the solvent are mixed and reacted to obtain a polyamic acid spinning solution.

[0063] Preferably, the diamine includes any one or a combination of at least two of 4,4'-diaminodiphenyl ether, p-phenylenediamine or 2,2'-bis(trifluoromethyl)diaminobiphenyl , more preferably 4,4'-diaminodiphenyl ether;

[0064] Preferably, the dianhydride includes any one or a combination of at least two of pyromellitic anhydride, biphenyltetracarboxylic dianhydride or hexafluorodianhydride, more preferably pyromellitic anhydride;

[0065] Preferably, the solvent includes N,N dimethylformamide and / or N,N dimethylacetamide;

[0066] As an optional embodiment of the present invention, the molar ratio of diamine and dianhydride is (0.98-1.02):(0.97-1.03). Typical but non-limiting molar ratios are 0.98:0.97, 0...

Embodiment 1

[0085] The present embodiment provides a method for preparing a composite integrated separator for a lithium-sulfur battery, comprising the following steps:

[0086] (a) Provide polyamic acid spinning solution: add 1.5 g of 4,4'-diaminodiphenyl ether to 14.6 g of N,N-dimethylformamide to dissolve, and then in an ice-water bath, add 1.6 g of pyromellitic anhydride was added to the reaction system, and after 6 hours of reaction, a polyamic acid spinning solution was obtained.

[0087] Put the polyamic acid spinning solution into a 10mL syringe, assemble the syringe with a metal needle, and fix it on the high-voltage electrospinning machine. 18kV, the injection speed is 15μL / min, the receiver speed is 30r / min, and the spinning time is about 2h, to obtain a polyamic acid fiber membrane with a thickness of 170μm;

[0088] (b) The polyamic acid fiber membrane is thermally imidized in the air, that is, the temperature is increased in stages, and the heating rate is 2 °C / min. The te...

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Abstract

The invention provides a lithium-sulfur battery composite integrated diaphragm, a preparation method and a lithium-sulfur battery, and relates to the technical field of lithium-sulfur batteries. The preparation method of the composite integrated diaphragm of the lithium-sulfur battery comprises the following steps: firstly, preparing a polyamide acid fiber membrane by adopting an electrostatic spinning technology, then carrying out thermal imidization treatment on the polyamide acid fiber membrane to obtain a polyimide fiber membrane, and then carrying out CO2 laser irradiation on the surface of the polyimide fiber membrane to obtain the composite integrated diaphragm of the lithium-sulfur battery. Wherein CO2 laser irradiates the polyimide fiber membrane, carbonization of the surface layer of the polyimide fiber membrane can be induced, porous carbon generated in the transient thermal shock process is rich in intrinsic defects, then a three-dimensional fluffy foam structure is constructed, and the formed porous carbon is seamlessly connected with the polyimide fiber membrane on the bottom layer; the porous carbon and polyimide fiber membrane composite integrated diaphragm has a well-penetrating pore structure, high mechanical stability, high flexibility and high heat resistance.

Description

technical field [0001] The invention relates to the technical field of lithium-sulfur batteries, in particular to a composite integrated separator of a lithium-sulfur battery, a preparation method and a lithium-sulfur battery. Background technique [0002] As a key component of lithium-sulfur batteries, the separator must not only ensure electronic insulation and lithium ion permeability, but also block the diffusion of polysulfides across the membrane and inhibit the shuttle effect. The traditional lithium-sulfur battery separators are mainly polyolefin separators, such as polypropylene (PP) separators, polyethylene (PE) separators, and multi-layer composite separators (PP / PE two-layer composite separator or PP / PE / PP three-layer composite separator). ). This type of separator has good chemical stability and high porosity, but has poor wettability to ether electrolytes, low liquid absorption rate, and poor thermal stability, which is likely to cause safety problems. The mo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M50/403H01M50/423H01M50/431H01M50/449H01M50/491H01M10/052
CPCH01M50/403H01M50/423H01M50/431H01M50/449H01M50/491H01M10/052Y02P70/50Y02E60/10
Inventor 张梦迪牟佳伟吴明铂胡涵董志亮陈蓓
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
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