Conductive binder for positive electrode of lithium ion battery, positive electrode of lithium ion battery and preparation method

A lithium-ion battery and conductive binder technology, applied in battery electrodes, non-aqueous electrolyte battery electrodes, secondary batteries, etc., can solve the problems of increased internal resistance of electrode materials, low ionic conductivity, and increased polarization resistance, etc. Achieve the effect of improving battery capacity, high lithium ion conductivity, and high ion conductivity

Inactive Publication Date: 2016-12-28
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] At present, the binders used in lithium-ion batteries are mainly organic fluoropolymers, such as PVDF, which have good stability and good adhesion to electrode materials, but their ion conductivity is low. As a result, the internal resistance of the electrode material increases, especially when the lithium-ion battery is charged and discharged at a high current, the polarization of the electrolyte salt increases, the polarization resistance increases, the extraction of lithium ions is hindered, and the discharge voltage drops rapidly, thus limiting the lithium-ion battery. Retention of charge and discharge capacity and improvement of energy density under high current charge and discharge

Method used

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  • Conductive binder for positive electrode of lithium ion battery, positive electrode of lithium ion battery and preparation method
  • Conductive binder for positive electrode of lithium ion battery, positive electrode of lithium ion battery and preparation method
  • Conductive binder for positive electrode of lithium ion battery, positive electrode of lithium ion battery and preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] In this embodiment, the conductive binder for the positive electrode of the lithium ion battery is a fluorine-containing sulfonimide lithium ion polymer (PFSI), and its structural formula is:

[0039]

[0040] Wherein, n is an integer from 500 to 1000, including 500 and 1000.

[0041] The preparation method of the above binder is: dissolving fluorine-containing sulfonimide ion polymer salt PFSI in acetonitrile, adding an equivalent amount of LiClO 4 , stirred and lithiated for 12 hours, filtered, removed the solvent, and dried thoroughly in a vacuum oven at 80°C to obtain a fluorine-containing sulfonimide lithium ion polymer, which was put into a desiccator for use.

[0042] The 19FNMR characterization figure of the fluorine-containing sulfonimide lithium ion polymer prepared above is as follows figure 1 shown. The measured number average molecular weight is 355775, and the average degree of polymerization is 830.

[0043] When using the fluorine-containing sulfon...

Embodiment 2

[0048] In this example, the conductive binder for the positive electrode of the lithium ion battery is a mixture of the fluorine-containing sulfonimide lithium ion polymer (PFSI) and polyvinylidene fluoride (PVDF) in Example 1 at a mass ratio of 1:1. made.

[0049] The preparation method of the fluorine-containing sulfonylimide lithium ion polymer (PFSI) is the same as that of Example 1.

[0050] The above-mentioned binder is used to make the positive electrode sheet of the lithium ion battery. The positive electrode sheet is based on a current collector aluminum foil, and an active material layer is coated on the surface of the base material. The active material layer is lithium iron phosphate LiFePO 4 The powder is used as the positive electrode active material, acetylene black is used as the conductive agent, and the mixture of the above-mentioned fluorine-containing sulfonimide lithium ion polymer (PFSI) and polyvinylidene fluoride (PVDF) at a mass ratio of 1:1 is used a...

Embodiment 3

[0061] In this embodiment, the conductive binder for the positive electrode of the lithium ion battery is the same as the binder for the positive electrode of the lithium ion battery in Example 1.

[0062] The preparation method of the binder is as follows: exchange the fluorine-containing sulfonimide ion polymer salt with a Nafion-H ion exchange column for hydrogen ion exchange, then add an equivalent LiOH solution and stir for lithiation for 12 hours, remove the solvent, and dry it in a vacuum oven Thoroughly dry at 80°C to obtain a fluorine-containing sulfonimide lithium ion polymer conductive adhesive, which is placed in a desiccator for use.

[0063] A lithium ion battery material using the above-mentioned binder. The positive electrode material is based on a current collector aluminum foil, and an active material layer is coated on the surface of the base material. The active material layer is lithium manganate (LiMn 2 o 4 ) powder as the positive electrode active mat...

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Abstract

The invention provides a conductive adhesive for a lithium ion battery positive pole. The adhesive comprises a fluorine-containing sulfimide lithium ion polymer. An ionic polymer main chain of the conductive adhesive comprises a superacid structure containing -SO2N-Li+SO2-, and the lithium ion can be effectively dissociated, so that the lithium ion conductivity is improved, and the battery capacity and battery charging and discharging cycle ratio under large-current charging and discharging are improved. Meanwhile, the electrochemical performance of the lithium ion battery taking the adhesive as a positive pole adhesive is stable, and the lithium ion battery is difficultly degraded along with the charging and discharging cycle, so that the service life of the battery is effectively prolonged.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a binder for positive electrodes of lithium ion batteries, a positive electrode of lithium ion batteries using the binder and a preparation method thereof. Background technique [0002] Since entering the 21st century, with the rapid development of social economy, energy, as the most basic power source, has been more widely used and demanded. The oil crisis and environmental pollution are two huge challenges facing the world, and the form is becoming more and more serious. Fuel vehicles are a major cause of both problems. Pure electric vehicles (EVs) and hybrid electric vehicles (HEVs) have the outstanding advantages of not using or using a small amount of fuel and almost no pollution emissions. The power battery is one of the key research and development parts. [0003] Lithium-ion batteries have become a hot spot in the research of new power supply ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/62H01M4/13H01M4/139
CPCH01M4/131H01M4/1391H01M4/623H01M10/0525Y02E60/10
Inventor 薛立新石倩茹魏增斌盛建芳张尧剑
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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