WS2/CNTs modified diaphragm of lithium-sulfur battery and preparation method of WS2/CNTs modified diaphragm

A lithium-sulfur battery and battery separator technology, which is applied in the field of new energy materials and devices, can solve the problems of incomplete material functions and limited improvement in battery performance, and achieves reduction of electrochemical polarization, good electronic pathways, and accelerated Effects of Electron and Ion Transport

Active Publication Date: 2020-11-10
HEFEI UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] However, most of the composite separators currently researched and developed are based on the principle of physical and / or chemical adsorption to limit the dissolution and shuttling of polysulfides in liquid electrolytes during charge and discharge, and the singleness of materials will also cause incomplete functions. , has a limited effect on improving the overall performance of the battery

Method used

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  • WS2/CNTs modified diaphragm of lithium-sulfur battery and preparation method of WS2/CNTs modified diaphragm
  • WS2/CNTs modified diaphragm of lithium-sulfur battery and preparation method of WS2/CNTs modified diaphragm
  • WS2/CNTs modified diaphragm of lithium-sulfur battery and preparation method of WS2/CNTs modified diaphragm

Examples

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Embodiment 1

[0040] This embodiment provides a lithium-sulfur battery WS 2 / CNTs modified diaphragm, which consists of two parts: a diaphragm substrate and a modified layer laid on one side of the diaphragm substrate. The separator substrate is a common commercial battery separator substrate, and the modified layer is laid on one side of the separator substrate by WS 2 / CNTs composite material.

[0041] The diaphragm substrate has a planar structure and a large number of through holes, which can be polypropylene (PP) porous membrane, polyethylene (PE) porous membrane, polyethylene / polypropylene composite porous membrane, polyimide diaphragm, polyethylene terephthalate One of the diester-based non-woven separators. In this example, the separator substrate was a commercially available porous polypropylene (PP) membrane (Celgard 2500).

[0042] This embodiment provides a lithium-sulfur battery WS 2 The preparation method of / CNTs modified separator comprises the following steps:

[0043] ...

Embodiment 2

[0068] The preparation method of this embodiment is the same as that of Example 1, except that the WS on the surface of the commercial battery PP separator (Celgard 2500) is suction-filtered in step (6). 2 The loading capacity per unit area of ​​CNTs is 0.48mg / cm 2 , the thickness of the modified layer is 12 μm, and other implementation conditions remain unchanged.

[0069] Compared with Example 1, the WS prepared in this example 2 The lithium-sulfur battery capacity, rate and cycle stability of the lithium-sulfur battery assembled with / CNTs modified separator are roughly the same as in Example 1: the initial discharge capacity at 0.5C is 1052mAh / g, and the specific capacity drops to 803.2mAh / g, the capacity retention rate is 76.3%; the discharge capacity of the first cycle of 1C cycle charge and discharge is 1023mAh / g, and the discharge capacity of the battery after 500 cycles of long cycle can still reach 665.4mAh / g, and the capacity retention rate is 65.0%. In addition, ...

Embodiment 3

[0071] The preparation method of this embodiment is the same as that of Example 1, except that the WS on the surface of the commercial battery PP separator (Celgard2500) is suction-filtered in step (6). 2 The loading capacity per unit area of ​​CNTs is 0.15mg / cm 2 , the thickness of the modified layer is 4 μm, and other implementation conditions remain unchanged.

[0072] Compared with Example 1, the WS prepared in this example 2The electrochemical performance of the lithium-sulfur battery assembled with / CNTs modified separator, such as capacity, rate and cycle stability, is significantly lower than that of Example 1: the initial discharge capacity at 0.5C is 1123mAh / g, and the specific capacity after 200 cycles of charge and discharge Dropped to 678.1mAh / g, the capacity retention rate is 60.4%; the discharge capacity of the first cycle of 1C cycle charge and discharge is 1083mAh / g, and the discharge capacity of the battery after 500 cycles of long cycle can still reach 617....

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Abstract

The invention belongs to the technical field of new energy materials and devices, and particularly relates to a WS2/CNTs modified diaphragm of a lithium-sulfur battery and a preparation method of theWS2/CNTs modified diaphragm. The WS2/CNTs modified diaphragm comprises a diaphragm matrix and a modified layer laid on the surface of one side of the diaphragm matrix, wherein the modified layer is composed of a WS2/CNTs composite material. Hydroxylated CNTs serve as a carrier, CTAB serves as a surfactant, TAA and WCl6 serve as an S source and a W source respectively, a WS2/CNTs composite materialis prepared through a one-step hydrothermal method, the WS2/CNTs composite material is subjected to suction filtration on the surface of one side of a commercial battery diaphragm base body, and themodified diaphragm for the lithium-sulfur battery is obtained. The WS2/CNTs modified diaphragm can effectively solve the shuttle effect problem of the lithium-sulfur battery and improve the specific capacity, coulombic efficiency and cycle life of the battery while ensuring the electrochemical reaction activity of the lithium-sulfur battery and the smooth penetration of lithium ions, and meanwhile, the overall mass of the modified layer is relatively light, so that the overall energy density of the lithium-sulfur battery is not influenced.

Description

technical field [0001] The invention belongs to the technical field of new energy materials and devices, in particular to a lithium-sulfur battery WS 2 / CNTs modified diaphragm and preparation method thereof. Background technique [0002] Lithium-sulfur battery is a new type of electrochemical energy storage system that uses sulfur as the positive electrode active material and metal lithium as the negative electrode. The theoretical specific capacity and specific energy are as high as 1675mAh g -1 and 2600Wh kg -1 , which is several times that of the current commercial lithium-ion batteries, and is rich in sulfur reserves and environmentally friendly, so lithium-sulfur batteries are recognized as a new generation of high-energy-density energy storage devices with the most development potential and application prospects. [0003] However, lithium-sulfur batteries are facing many key scientific and technical problems to be solved, mainly including the electronic and ionic in...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M2/14H01M10/052
CPCH01M10/052Y02E60/10
Inventor 刘家琴吴玉程高傲王忠杰张琪闫健
Owner HEFEI UNIV OF TECH
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