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High voltage-resistant polyoxyethylene-based composite electrolyte as well as preparation method and application thereof

A polyethylene oxide and composite electrolyte technology, which is applied in the manufacture of electrolyte batteries, electrolytes, non-aqueous electrolyte batteries, etc., can solve the problems of incompatibility and narrow chemical window, improve energy density, inhibit violent decomposition, and widen the electrochemical window. Effect

Pending Publication Date: 2021-07-13
SHANDONG IND TECH RES INST OF ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the electrochemical window of polyoxyethylene-based electrolytes is relatively narrow, and it will start to decompose at 3.8V. Currently, it is only used to match low-voltage cathode materials such as lithium iron phosphate, but not high-voltage cathode materials such as lithium cobaltate.

Method used

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  • High voltage-resistant polyoxyethylene-based composite electrolyte as well as preparation method and application thereof
  • High voltage-resistant polyoxyethylene-based composite electrolyte as well as preparation method and application thereof
  • High voltage-resistant polyoxyethylene-based composite electrolyte as well as preparation method and application thereof

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preparation example Construction

[0035] The present invention also provides a preparation method of the high-voltage resistant polyoxyethylene-based composite electrolyte described in the above technical solution, comprising the following steps:

[0036] Coating a mixed solution comprising polyethylene oxide, a first lithium salt, a first solvent, and lithium-conducting inorganic particles on a mold, performing first drying, and stripping to obtain a main body layer of a polyethylene oxide-based composite electrolyte;

[0037] Coating the mixed solution including the polymer, the second lithium salt, the ionic liquid and the second solvent on at least one side surface of the polyoxyethylene-based composite electrolyte body, and performing a second drying to obtain a high-voltage resistant polyoxyethylene-based composite electrolyte electrolyte.

[0038] Unless otherwise specified, the present invention has no special requirements on the sources of the raw materials used, and commercially available products we...

Embodiment 1

[0061] Dissolve 2.5g polyethylene oxide (molecular weight: 600,000) and 1.0g LiTFSI (lithium bis(trifluoromethanesulfonyl)imide) in 25g anhydrous acetonitrile, stir well to form a uniform solution, then add 1.65g garnet-type Inorganic electrolyte LLZTO (lithium lanthanum zirconium tantalum oxide) particles, after stirring for 12 hours, a uniform mixed solution was obtained, and it was coated on a clean release film with a spatula, and left to stand at room temperature for 12 hours to evaporate most of the solvent. Then transfer to a vacuum oven at 60°C to dry for 12 hours, and after manual stripping, obtain the main body layer of polyoxyethylene-based composite electrolyte (thickness is 40 μm);

[0062] Dissolve 0.83g LiTFSI in 8.0g N,N-dimethylformamide, then add 2.4g polyvinylidene fluoride-hexafluoropropylene, stir for 6h to fully dissolve, and finally add 2.77g N-propyl-N -Methylpyrrolidine bis(trifluoromethanesulfonyl)imide salt was stirred again for 6h to obtain a unifor...

Embodiment 2

[0065] Dissolve 2.5g of polyethylene oxide (molecular weight: 600,000) and 1.36g of LiTFSI bis(trifluoromethanesulfonyl)imide lithium in 25g of anhydrous acetonitrile, stir well to form a uniform solution, and then add 1.07g of garnet-type Inorganic electrolyte particles (LLZTO), stir for 12 hours to get a uniform mixture, and apply it on a clean release film with a scraper, then let it stand at room temperature for 12 hours, evaporate most of the solvent, and then transfer it to 60 ° C Dry in a vacuum oven for 12 hours, and after manual stripping, obtain the main body layer of polyoxyethylene-based composite electrolyte (thickness is 40 μm);

[0066] Then, dissolve 0.86g of LiTFSI lithium bis(trifluoromethanesulfonyl)imide in 7.2g of N,N-dimethylformamide, then add 2.4g of polyvinylidene fluoride-hexafluoropropylene, stir for 6h to fully Dissolve, and finally add 2.74g 1-ethyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide salt and stir again for 6h to obtain a uniform ...

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Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a high voltage-resistant polyoxyethylene-based composite electrolyte. According to the invention, at least one side of a polyoxyethylene-based composite electrolyte main body layer is introduced with a stable polymer electrolyte containing the ionic liquid as the interface layer, so that the direct contact between the composite electrolyte and an electrode is prevented, an electrochemical window of the polyoxyethylene-based electrolyte is indirectly widened, and the severe decomposition of the polyoxyethylene-based electrolyte under a high voltage is effectively inhibited, and accordingly the application of the polyoxyethylene-based electrolyte in a lithium cobalt oxide type high-voltage positive electrode system is realized. The result of the embodiment shows that the electrochemical window of a lithium-electrolyte-stainless steel battery assembled by the high voltage-resistant polyoxyethylene-based composite electrolyte provided by the invention can reach 4.6 V, and the capacity retention ratio of a lithium cobalt oxide battery assembled by the high voltage-resistant polyoxyethylene-based composite electrolyte after 50 cycles at 4.5 V is 89%.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a high-voltage-resistant polyoxyethylene-based composite electrolyte and a preparation method and application thereof. Background technique [0002] At present, the vast majority of solid-state batteries in research and trial production use cobalt-containing positive electrodes, mainly lithium cobalt oxide and ternary materials. However, for high-voltage cathode materials such as lithium cobaltate, under the commonly used cut-off voltage of 4.2V, the lithium cobaltate cathode can only release about half of the lithium ions, releasing a capacity of about 140mAh / g. With the further increase of the charge cut-off voltage, lithium cobalt oxide can release higher capacity, but it is also accompanied by the problem of violent decomposition of the electrolyte under the catalysis of tetravalent cobalt ions. In order to further increase the energy density of sol...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/0565H01M10/058H01M10/0525
CPCH01M10/0565H01M10/058H01M10/0525H01M2300/0094Y02P70/50Y02E60/10
Inventor 王秀丽蔡丹涂江平
Owner SHANDONG IND TECH RES INST OF ZHEJIANG UNIV