Local high-concentration electrolyte additive for lithium metal secondary battery and application

A secondary battery and electrolyte technology, applied in secondary batteries, lithium batteries, non-aqueous electrolyte batteries, etc., can solve the problems of not being able to balance thermal stability and provide sufficient fluorine sources, to prevent continuous adverse reactions, improve conductivity The effect of enhancing and inhibiting the growth of lithium dendrites

Pending Publication Date: 2022-04-15
HUAZHONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Aiming at the defects of the prior art, the purpose of the present invention is to provide a local high-concentration electrolyte additive for lithium metal secondary batteries and its application. A new type of additive is used to formulate the components of the lithium metal battery electrolyte, aiming to solve the problem of Existing electrolyte diluents cannot balance thermal stability and provide sufficient fluorine source

Method used

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  • Local high-concentration electrolyte additive for lithium metal secondary battery and application
  • Local high-concentration electrolyte additive for lithium metal secondary battery and application
  • Local high-concentration electrolyte additive for lithium metal secondary battery and application

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preparation example Construction

[0041] The preparation method of a local high-concentration electrolyte provided by the present invention comprises the following steps: adding a conductive lithium salt to an organic solvent to fully disperse to obtain a high-concentration lithium salt solution, and the conductive lithium salt in the high-concentration lithium salt solution is The concentration is greater than or equal to 3mol / L; diluent and additives are sequentially added to the high-concentration lithium salt solution, so that the high-concentration lithium salt solution is fully diluted to obtain a local high-concentration electrolyte. In the method for preparing the electrolytic solution of the present invention, the lithium salt is added to the organic solvent, which avoids volatilization of the organic solvent due to the release of a large amount of heat when the organic solvent is added to the lithium salt.

[0042] In some embodiments, the concentration of the conductive lithium salt in the partially ...

Embodiment 1

[0048] This embodiment prepares a local high-concentration electrolyte solution for a lithium metal secondary battery, which specifically includes the following steps:

[0049] (1) Add the conductive lithium salt LiFSI to the ether solvent DME to fully disperse to obtain a dispersed high-concentration lithium salt solution;

[0050] (2) Add the diluent FB to the dispersed high-concentration lithium salt solution to fully dilute, and then add the additive 3FB, wherein the ratio of the amount of substances of LiFSI, DME, FB and 3FB is 1:1.2:2.8:0.2, A new electrolyte FB / 3FB-DHCE was obtained.

[0051] The local high-concentration electrolyte solution prepared in this embodiment is highly dispersed and clear, as figure 1 shown.

Embodiment 2

[0053] The copper sheet, separator and lithium sheet were assembled in an argon-protected glove box to assemble a lithium-copper half-cell, and the electrolyte FB / 3FB-DHCE prepared in Example 1 was added dropwise. The button cell assembled above was tested for Coulombic efficiency, and the amount of deposited lithium metal was 1mAhcm -2 , with a current density of 1mA cm -2 . From figure 2 It can be seen that the coulombic efficiency of the lithium-copper half-cell assembled with the local high-concentration electrolyte added with 3FB is still above 99% after 200 cycles.

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Abstract

The invention belongs to the technical field of high-specific-energy secondary batteries, and particularly discloses a local high-concentration electrolyte additive for a lithium metal secondary battery and application, the additive is an aromatic compound and is composed of a benzene ring and substituent groups, at least two hydrogen atoms on the benzene ring are substituted by fluorine atoms, and the substituent groups are substituted by fluorine atoms on the benzene ring. The rest hydrogen atoms are retained or substituted by alkyl, halogenated alkyl and halogen atoms; the additive is used for being added into the local high-concentration electrolyte of the lithium metal secondary battery, can be highly soluble with the local high-concentration electrolyte, and does not change the original solvation structure of the local high-concentration electrolyte; and the interaction among lithium ions, an organic solvent and anions can be weakened, so that the ionic conductivity of the local high-concentration electrolyte is improved. The additive disclosed by the invention is added into the existing local high-concentration electrolyte, so that the additive not only has excellent thermal stability, but also can generate components of a stable interface at the positive electrode and the negative electrode of a battery, and the coulombic efficiency and the cycle life of the battery under a high-voltage condition are greatly improved.

Description

technical field [0001] The invention belongs to the technical field of high specific energy secondary batteries, and more specifically relates to a local high-concentration electrolyte additive for lithium metal secondary batteries and its application. Background technique [0002] The increasingly serious problem of global environmental pollution and the rapid development of renewable clean energy have drawn people's attention to the development of green, safe, efficient and inexpensive electrochemical energy storage systems. At present, lithium-ion batteries using graphite anodes occupy a dominant position in the field of energy storage, and their development is close to the upper limit. Therefore, in order to meet human requirements for higher energy density energy storage devices, it is necessary to seek higher-capacity anode materials. Lithium metal The negative electrode is known as the "holy grail" in negative electrode materials, which is enough to see its important ...

Claims

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Application Information

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IPC IPC(8): H01M10/0567H01M10/052
CPCY02E60/10
Inventor谢佳曾子琪张涵
OwnerHUAZHONG UNIV OF SCI & TECH