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Separation membrane and lithium secondary battery comprising same

A lithium secondary battery and diaphragm technology, applied in the field of lithium secondary batteries, can solve problems such as reduced charge and discharge efficiency, complexity, and deterioration

Active Publication Date: 2020-05-01
LG ENERGY SOLUTION LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, the lithium polysulfides cause a shuttle reaction during charging, resulting in a significant decrease in charge-discharge efficiency
[0006] In order to solve these problems, a method of adding an additive having sulfur-adsorbing properties has been proposed, however, the problem of deterioration has newly arisen, generating additional battery side reactions
In view of the above, in order to delay the outflow of sulfur, which is the positive electrode active material, methods of adding metal chalcogenides, alumina, etc., or coating the surface with oxidized carbonate, etc., have been proposed, however, these methods either cause sulfur to be present during processing The drain or method is complex and also limits the amount of active material, i.e. sulfur, to be introduced (i.e. loading)

Method used

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  • Separation membrane and lithium secondary battery comprising same
  • Separation membrane and lithium secondary battery comprising same
  • Separation membrane and lithium secondary battery comprising same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0103] (1) Preparation of diaphragm

[0104] As a porous substrate, a polyethylene (50% porosity) film with a thickness of 20 μm was prepared.

[0105] Partially reduced graphene oxide (oxygen atom content in graphene is 15%) aqueous dispersion (concentration is 0.002% by weight) and lithiated Nafion (DuPont) aqueous dispersion (concentration is 0.25 mg / mL) after mixing, ultrasonic waves were applied thereto for 8 hours to prepare a coating liquid (weight ratio of partially reduced graphene oxide:lithiated Nafion=1:12.5).

[0106] The coating solution was poured on the porous substrate, and the resultant was filtered under reduced pressure to obtain a concentration of 10 μg / cm on the surface of the porous substrate facing the positive electrode. 2 Form a coating. The resultant was dried at 70° C. for 24 hours to prepare a separator. Here, the coating is measured to have a thickness of approximately 0.4 μm±0.2 μm.

[0107] (2) Lithium secondary battery

[0108] Conductive ...

Embodiment 2

[0111] Except at 20μg / cm 2 That is, a lithium secondary battery was produced in the same manner as in Example 1, except that the coating amount was twice that of Example 1 to form a coating layer on the porous substrate.

experiment example 1

[0119] Each of the lithium secondary batteries manufactured in Examples and Comparative Examples was operated under charge / discharge conditions of 0.1C / 0.1C (2.5 cycles) and 0.2C / 0.2C. Initial charge and discharge capacities were measured, and after 25 cycles were performed, changes in capacity were determined.

[0120] figure 2 It is a graph showing the lifetime characteristics of the lithium secondary batteries produced in Example 1 and Comparative Examples 1 to 3. When examining figure 2 It can be seen that the battery of Example 1 has a higher capacity retention rate relative to the initial charge and discharge and shows a capacity improvement effect, and compared with the comparative example 1 without coating, the reduced graphene oxide coating only Example 1 has excellent capacity retention compared to Comparative Example 2 which is coated with a lithiated Nafion polymer or Comparative Example 3 which is only coated with lithiated Nafion polymer.

[0121] image 3 ...

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Abstract

The present invention relates to a separation membrane and a lithium secondary battery comprising same, which can address a problem resulting from lithium polysulfide generated in the conventional lithium secondary batteries, by having a separation membrane formed by coating at least one surface of a porous substrate with a partially reduced graphene oxide and a lithium ion conducting polymer.

Description

technical field [0001] This application claims priority and benefit from Korean Patent Application No. 10-2017-0139968 filed with the Korean Intellectual Property Office on October 26, 2017, the entire contents of which are incorporated herein by reference. [0002] The present invention relates to a separator capable of solving problems caused by lithium polysulfide and a lithium secondary battery including the separator. Background technique [0003] As electronic products, electronic devices, communication devices, etc. have recently become rapidly smaller and lighter, and the demand for electric vehicles has become increasingly prominent due to environmental concerns, there is a need to improve the performance of secondary batteries used as power sources for these products greatly increase. Among them, lithium secondary batteries have received considerable attention as high-performance batteries due to their high energy density and high standard electrode potential. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M10/052H01M50/403H01M50/417H01M50/426H01M50/431H01M50/451H01M50/457H01M50/489H01M50/497
CPCH01M10/052H01M4/382H01M4/38Y02E60/10H01M50/446H01M50/417H01M50/457H01M50/451H01M50/489H01M50/431H01M50/426H01M50/403H01M50/497H01M50/491H01M50/449H01M50/463H01M50/411H01M50/414H01M10/0525H01M2220/20
Inventor 宋知恩孙权男梁斗景
Owner LG ENERGY SOLUTION LTD