A functional separator coating material for protecting lithium metal negative electrodes and its preparation method and application

A technology of lithium metal negative electrode and coating material, applied in the direction of lithium battery, structural parts, battery pack parts, etc., can solve the problems of limited lithium ion diffusion rate, reduced battery coulomb efficiency, consumption of electrolyte, etc. Ion concentration, reducing space charge effects, slowing down stacking effects

Active Publication Date: 2022-02-18
SOUTH CHINA NORMAL UNIVERSITY
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0002] The theoretical specific capacity of lithium metal is 3860 mAh / g, and its standard potential is -3.04 V. Compared with other anode materials, it has obvious advantages and is a promising anode material for lithium batteries. The development of lithium metal batteries, such as the phenomenon of lithium dendrites, as the number of cycles of the battery increases, the dendrites gradually grow, and even pierce the separator, causing safety problems. At the same time, the formation of dead lithium will not only cause the battery Coulombic efficiency At the same time, the SEI film on its surface will also consume the electrolyte. The combination of the above factors means that the commercial application of lithium metal batteries still has a long way to go.
[0003] At present, many researchers have conducted many studies on the formation mechanism of lithium dendrites. However, the growth of lithium dendrites involves many fields such as electrochemistry, interfacial science, crystallography, thermodynamics, etc., and there is still no universal mechanism expression. , one of the theories is that in the lithium ion deposition process, limited by the diffusion rate of lithium ions, there is a concentration gradient in the electrolyte. When the current density increases to a certain level, the lithium ions are exhausted on the lithium negative electrode side. This creates localized space charges leading to the formation of lithium dendrites

Method used

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  • A functional separator coating material for protecting lithium metal negative electrodes and its preparation method and application
  • A functional separator coating material for protecting lithium metal negative electrodes and its preparation method and application
  • A functional separator coating material for protecting lithium metal negative electrodes and its preparation method and application

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Embodiment 1

[0035] Preparation of a functional separator coating material-trihydroxyaldehyde-hydrazine-covalent organic framework:

[0036] Take 18 mg of 2,4,6-trihydroxy-1,3,5-benzenetricarbaldehyde and 64 μL of hydrazine hydrate (the molar ratio is 2:30), add 3 mL of methanol, 3 mL of tetrahydrofuran, and then add 6 mol / L acetic acid solution, the addition of acetic acid solution is 10% of the total volume of the above mixture, then pass through argon and seal it, place the above mixed solution in a 120°C oven for 72 h, and use 1, 4-dioxane, tetrahydrofuran and acetone were washed to obtain the red powder membrane coating material-trihydroxyaldehyde-hydrazine-covalent organic framework, such as figure 2 A schematic diagram of the reaction of a trihydroxyaldehyde-hydrazine-covalent organic framework is shown;

[0037] Such as figure 1 It is the SEM scanning image of trihydroxy aldehyde-hydrazine-covalent organic framework at different sizes, and the microscopic image of trihydroxy al...

Embodiment 2

[0040] Preparation of a functional separator coating material-trihydroxyaldehyde-hydrazine-covalent organic framework:

[0041] Take 18 mg of 2,4,6-trihydroxy-1,3,5-benzenetricarbaldehyde and 85 μL of hydrazine hydrate (the molar ratio is 1:20), add 3 mL of methanol, 3 mL of tetrahydrofuran, and then add 6 mol / L acetic acid solution, the addition of acetic acid solution is 12% of the total volume of the above mixture, then pass through argon and seal, place the above mixed solution in an oven at 120°C for 72 h, and use 1, 4-dioxane, tetrahydrofuran and acetone are washed to obtain the red powder membrane coating material-trihydroxyaldehyde-hydrazine-covalent organic framework;

[0042] Mix 0.16 g of trihydroxyaldehyde-hydrazine-covalent organic framework, 0.06 g of 5% aqueous binder LA132, and 0.04 g of conductive agent carbon black (the mass ratio of the three is 4:2:1), and then drop 2.4 Prepare the slurry with n-propanol aqueous solution in mL, and coat it on one side of th...

Embodiment 3

[0044] Preparation of a functional separator coating material-trihydroxyaldehyde-hydrazine-covalent organic framework:

[0045] Take 18 mg of 2,4,6-trihydroxy-1,3,5-benzenetricarbaldehyde and 71 μL of hydrazine hydrate (the molar ratio is 3:50), add 3 mL of methanol, 3 mL of tetrahydrofuran, and then add 6 mol / L acetic acid solution, the addition of acetic acid solution is 15% of the total volume of the above mixture, then pass through argon and seal, place the above mixed solution in an oven at 120°C for 72 h, and use 1, 4-dioxane, tetrahydrofuran and acetone are washed to obtain the red powder membrane coating material-trihydroxyaldehyde-hydrazine-covalent organic framework;

[0046] Mix 0.20 g of trihydroxyaldehyde-hydrazine-covalent organic framework, 0.08 g of 5% aqueous binder LA132 and 0.04 g of conductive agent carbon black (the mass ratio of the three is 5:2:1), and then drop 2 Prepare the slurry with n-propanol aqueous solution in mL, and coat it on one side of the...

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Abstract

The invention belongs to the technical field of electrochemical diaphragm materials, and in particular relates to a functional diaphragm coating material for protecting lithium metal negative electrodes, a preparation method and application thereof. The diaphragm coating material is a trihydroxy aldehyde-hydrazine-covalent organic framework, mixing 2,4,6-trihydroxy-1,3,5-benzenetricarbaldehyde and hydrazine hydrate, adding an organic mixed solvent, High-temperature reaction in the environment, the obtained reaction product is washed and dried, and the obtained red powder is the trihydroxy aldehyde-hydrazine-covalent organic framework coating material. The prepared trihydroxy aldehyde-hydrazine-covalent organic framework has abundant polar functional group hydroxyl groups. This coating material is applied to the protection of lithium metal. Through the lithium-friendly effect of polar groups, it fixes anions and promotes the dissolution of electrolyte salts. Ionization, increase the migration number of lithium ions, increase the concentration of lithium ions near the lithium negative electrode, reduce the space charge effect of cations, reduce the growth of lithium ion tips, and effectively inhibit the performance of lithium dendrites.

Description

technical field [0001] The invention belongs to the technical field of electrochemical diaphragm materials, and in particular relates to a functional diaphragm coating material for protecting lithium metal negative electrodes, a preparation method and application thereof. Background technique [0002] The theoretical specific capacity of lithium metal is 3860 mAh / g, and its standard potential is -3.04 V. Compared with other anode materials, it has obvious advantages and is a promising anode material for lithium batteries. The development of lithium metal batteries, such as the phenomenon of lithium dendrites, as the number of cycles of the battery increases, the dendrites gradually grow, and even pierce the separator, causing safety problems. At the same time, the formation of dead lithium will not only cause the battery Coulombic efficiency At the same time, the SEI film on its surface will also consume the electrolyte. The combination of the above factors means that the co...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D259/00H01M50/403H01M50/449H01M50/46H01M50/491H01M10/052
CPCC07D259/00H01M10/052Y02E60/10
Inventor 蔡跃鹏洪旭佳袁丽娟邢军伟
Owner SOUTH CHINA NORMAL UNIVERSITY
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