Preparation method of lithium ion battery composite diaphragm

A technology for lithium-ion batteries and composite diaphragms, applied in secondary batteries, battery components, circuits, etc., can solve the problems of reducing the mechanical strength of the diaphragm, improve safety performance and electrochemical performance, increase the degree of desolvation, The effect of increasing the conduction rate

Active Publication Date: 2018-11-09
HEFEI GUOXUAN HIGH TECH POWER ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the gel electrolyte formed by polyvinylidene fluoride under the condition of being activated by the electrolyte greatly reduces the mechanical strength of the separator.

Method used

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  • Preparation method of lithium ion battery composite diaphragm

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Experimental program
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Effect test

Embodiment 1

[0024] The preparation method of a kind of lithium-ion battery composite diaphragm that the present invention proposes comprises the following steps:

[0025] S1. Preparation of modified graphene: Weigh 10 mg graphene nanosheets and 100 mg 4-carboxybenzene diazonium salt at normal temperature, put them into 10 mL of 100 mmol / L hypophosphorous acid aqueous solution, stir well, and avoid Leave alone for 24 hours to carry out the modification reaction of graphene, filter and wash the obtained modified graphene aqueous solution, place in an oven and dry at 50°C for 5 hours to obtain modified graphene covalently modified by benzene carboxyl groups;

[0026] S2. Preparation of modified graphene dispersion: add the modified graphene in S1 to 100 mL of N-dimethylacetamide, and ultrasonically disperse for 30 minutes to obtain a modified graphene dispersion;

[0027] S3. Preparation of modified graphene / organic polymer: dissolve polyvinylidene fluoride in N-dimethylacetamide, add modifi...

Embodiment 2

[0030] The preparation method of a kind of lithium-ion battery composite diaphragm that the present invention proposes comprises the following steps:

[0031] S1. Preparation of modified graphene: Weigh 10 mg graphene nanosheets and 100 mg 4-carboxybenzene diazonium salt at normal temperature, put them into 10 mL of 100 mmol / L hypophosphorous acid aqueous solution, stir well, and avoid Leave alone for 24 hours to carry out the modification reaction of graphene, filter and wash the obtained modified graphene aqueous solution, place in an oven and dry at 50°C for 5 hours to obtain modified graphene covalently modified by benzene carboxyl groups;

[0032] S2. Preparation of the modified graphene dispersion: add the modified graphene to 100 mL of N-dimethylacetamide, and disperse it ultrasonically for 30 minutes to obtain the modified graphene dispersion;

[0033] S3. Preparation of modified graphene / organic polymer: dissolve polyvinylidene fluoride in N-dimethylacetamide, add mod...

Embodiment 3

[0036] The preparation method of a kind of lithium-ion battery composite diaphragm that the present invention proposes comprises the following steps:

[0037] S1. Preparation of modified graphene: Weigh 10 mg graphene nanosheets and 100 mg 4-carboxybenzene diazonium salt at normal temperature, put them into 10 mL of 100 mmol / L hypophosphorous acid aqueous solution, stir well, and avoid Leave alone for 24 hours to carry out the modification reaction of graphene, filter and wash the obtained modified graphene aqueous solution, place in an oven and dry at 60°C for 5 hours to obtain modified graphene covalently modified by benzene carboxyl group;

[0038] S2. Preparation of the modified graphene dispersion: add the modified graphene to 100 mL of N-dimethylacetamide, and disperse it ultrasonically for 50 minutes to obtain the modified graphene dispersion;

[0039] S3. Preparation of modified graphene / organic polymer: dissolve polyvinylidene fluoride in N-dimethylacetamide, add modi...

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Abstract

Relating to the technical field of lithium ion batteries, the invention discloses a preparation method of a lithium ion battery composite diaphragm. The method includes the steps of: preparation of modified graphene, preparation of modified graphene dispersion liquid, preparation of a modified graphene/organic polymer, and preparation of the diaphragm. According to the invention, the modified graphene/organic polymer is precipitated on the surface of a polyolefin diaphragm, the prepared composite diaphragm has the chemical stability, electrochemical stability, thermodynamic stability, flexibility and high porosity of an organic polymer modified diaphragm and the high mechanical strength, fast heat dissipation and other characteristics of graphene, the modifying phenylcarboxyl on graphene can interact with lithium ions in the electrolyte solution, the desolvation degree of lithium ions can be enhanced to improve the lithium ion conduction rate, the hydrophilic group carboxyl also can improve the wettability of a base membrane to the electrolyte solution, and the prepared lithium ion composite diaphragm can improve the safety performance and electrochemical performance of lithium ionbatteries.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a preparation method of a lithium ion battery composite diaphragm. Background technique [0002] In lithium-ion batteries, the separator is a very important component. Its main function is to physically separate the positive and negative electrodes and prevent the passage of electrons so as not to cause a short circuit, while allowing the conduction of lithium ions. The performance of the separator directly determines the internal resistance of the battery, the adsorption of the electrolyte, the conduction of lithium ions, etc., which greatly affects the electrochemical performance and safety performance of the battery. Nowadays, polyolefin materials such as polyethylene (PE) and polypropylene (PP) occupy a dominant position in the separator market due to their excellent mechanical properties, chemical stability and low cost. However, the thermal stability of this...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/0525
CPCH01M10/0525H01M50/403H01M50/446H01M50/449Y02E60/10
Inventor 李智柳盼盼刘俊杰魏锴代北北
Owner HEFEI GUOXUAN HIGH TECH POWER ENERGY
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