Battery diaphragm material, preparation method thereof and application of battery diaphragm material

A battery separator and coating material technology, applied in fuel cells, battery electrodes, secondary batteries, etc., can solve problems such as failure, low capacity of lithium-ion batteries, and deterioration of negative electrode performance, so as to improve Coulombic efficiency, improve cycle performance, Effect of Specific Capacity Improvement

Active Publication Date: 2020-01-31
SOUTH CHINA NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

With the continuous charge and discharge under high temperature conditions, the redox reaction between the positive electrode material and the interface electrolyte will continue, and even the electrolyte will be decomposed, and metal ions will be deposited on the negative electrode, resulting in the deterioration of the negative electrode performance, and finally lead to the failure of the lithium-ion battery due to its low capacity.

Method used

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  • Battery diaphragm material, preparation method thereof and application of battery diaphragm material
  • Battery diaphragm material, preparation method thereof and application of battery diaphragm material
  • Battery diaphragm material, preparation method thereof and application of battery diaphragm material

Examples

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preparation example Construction

[0026] A method for preparing a battery diaphragm coating material of the present invention, comprising: dissolving PVDF and covalent organic framework material in N-methylpyrrolidone and stirring evenly; said PVDF, covalent organic framework material and N-methylpyrrolidone The mass ratio of pyrrolidone is 20:(70-85):(5-10). Among them, PVDF has good chemical stability and temperature characteristics, excellent mechanical properties and processability, and has a positive effect on improving bonding performance. If other types of resins are used instead of PVDF, such as sodium hydroxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR), if CMC is too brittle, it will cause the pole piece to drop powder, and the dispersion effect of SBR is not good, which will affect the cycle performance of the material. negative impacts.

[0027] Preferably, the organic solvent is a mixed solution of 1,4-dioxane and mesitylene.

[0028] Specifically, the covalent organic framework mate...

Embodiment 1

[0037] Prepare covalent organic framework materials (Covalent Organic Frameworks, COFs), by mass percentage, its raw material components are as follows:

[0038] 1,3,5-tris(4-aminophenyl)benzene (TPB) 54.6%,

[0039] 2,5-dimethoxy-1,4-dicarboxybenzene (DMTP) 45.4%,

[0040] Concrete preparation steps are as follows:

[0041] Dissolve 1,3,5-tris(4-aminophenyl)benzene (TPB) and 2,5-dimethoxy-1,4-dimethylaldehydebenzene (DMTP) in organic solvent 1,4-dioxane Ring and mesitylene, ultrasonic, control ultrasonic time is 5-10 minutes. Add 1-3% acetic acid. Then, under an inert protective atmosphere, the mixture was reacted at 120° C. for 3 days, and the obtained product was a yellow solid. Finally, the obtained yellow solid was repeatedly washed with 1,4-dioxane, tetrahydrofuran and absolute ethanol for 2-3 times, and then dried in vacuum for 12 hours. The stated percentages are all mass percentages.

[0042] After detection, the transmission electron microscope scanning image (...

Embodiment 2

[0050] Example 2 Application of COFs Modified Diaphragm: NCM811 as a cathode material for a lithium ion battery diaphragm

[0051] The COFs modified diaphragm prepared in Example 1 was cut into a diameter of 18 mm, used as a diaphragm for a lithium-ion battery, and NCM811 was used as a positive electrode material to assemble the battery.

[0052] After the separator was assembled into a battery, the cyclic voltammetry was measured. Figure 4 It is the cycle diagram of NCM811. It can be seen from the comparison that at room temperature, the half-cell prepared by mixing the separator synthesized by COFs and the half-cell prepared by unmixed CoFs are charged and discharged three times at a rate of 0.3C. The specific capacity Both remain at about 200mAh / g, and the Coulombic efficiency is 100% after 3 cycles, and when the two batteries are charged and discharged 150 times at a rate of 1C, it is found that the specific capacity of the half-cell prepared by this method is between 200...

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Abstract

The invention provides a preparation method of a battery diaphragm coating material. The preparation method comprises the following steps that: PVDF and a covalent organic framework material are dissolved in an organic solvent, and are uniformly stirred; the ratio of the PVDF to the covalent organic framework material to N-methyl pyrrolidone is 20:(70 to 85):(5 to 10). When the material is appliedto the preparation of a lithium ion battery diaphragm, the problem of metal dissolution which appears when a transition metal oxide is used as a positive electrode material can be effectively solved;and the prepared diaphragm can effectively adsorb metal ions and prevent the metal ions from being deposited to a negative electrode in a charging and discharging process, so that the cycle performance of the transition metal oxide positive electrode material is improved.

Description

technical field [0001] The invention belongs to the field of battery materials, and in particular relates to a battery diaphragm material and a preparation method and application thereof. Background technique [0002] As a secondary battery, lithium-ion battery has the advantages of high voltage, large specific energy, long cycle life, good safety performance, small self-discharge, fast charging speed, etc. It is currently the battery system with the best comprehensive performance and a modern high-performance battery system. A typical representative of the battery, it is widely used in the power support of information technology, electric vehicles and hybrid vehicles, aerospace and other fields. Lithium-ion batteries have been developed for decades. [0003] A lithium-ion battery is composed of a positive electrode, a negative electrode, a separator, and an electrolyte, and both the positive and negative electrode materials can intercalate and extract lithium ions. It wor...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/0525
CPCH01M10/0525H01M50/411H01M50/44H01M50/461H01M50/403Y02E60/10H01M8/0228H01M50/449H01M4/133H01M4/131H01M4/587H01M50/426H01M4/485H01M4/505H01M4/525H01M4/583
Inventor 李伟善温玉铖陈荟杨陈嘉威卢奕彤车艳霞
Owner SOUTH CHINA NORMAL UNIVERSITY
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