Method for surface modification of ternary cathode material for lithium ion batteries by fluorine-based ionic liquid

A technology of lithium-ion batteries and ionic liquids, applied in battery electrodes, electrical components, secondary batteries, etc., can solve the problems of reducing the initial efficiency of materials, deteriorating specific capacity, and aggravating lithium-nickel mixing, so as to facilitate intercalation/extraction , avoid direct contact, reduce the effect of side effects

Pending Publication Date: 2019-08-16
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

However, these coating processes often involve high temperature sintering (≥700°C), such as TiO 2 、Al 2 o 3 , AlPO 4 Coating, high-temperature calcination will intensify the mixing of lithium and nickel, reduce the first-time efficiency and specific capacity of the material, and deteriorate the cycle performance of the material

Method used

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  • Method for surface modification of ternary cathode material for lithium ion batteries by fluorine-based ionic liquid
  • Method for surface modification of ternary cathode material for lithium ion batteries by fluorine-based ionic liquid
  • Method for surface modification of ternary cathode material for lithium ion batteries by fluorine-based ionic liquid

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Experimental program
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Effect test

Embodiment 1

[0027] Weigh 1.0g LiNi 0.6 co 0.2 mn 0.2 o 2 Disperse the positive electrode material into 10g of fluorine-based ionic liquid 1-butyl-2,3-dimethylimidazolium tetrafluoroborate (alkylimidazolium tetrafluoroborate), and stir vigorously (500r / min) at room temperature 6h, then washed and filtered with absolute ethanol three times, dried at 60°C for 12h, and calcined at 300°C for 4h to obtain the fluorine-based ionic liquid surface-modified ternary cathode material of the present invention. After being modified by fluorine-based ionic liquids, its microscopic morphology is still maintained (see figure 1 and figure 2 ) and the crystal structure did not change (see image 3 ). The LiNi modified by fluorine-based ionic liquid 0.6 co 0.2 mn 0.2 o 2 The positive electrode material (NCM@LiF) was assembled into a battery. At 2.8-4.3V, 1C rate, its discharge specific capacity was 171.8mAh / g, and after 100 cycles, its discharge specific capacity was still 151.1mAh / g, showing excell...

Embodiment 2

[0029] Weigh 5.0g LiNi 0.8 co 0.1 mn 0.1 o 2 The positive electrode material is dispersed into 50g of fluorine-based ionic liquid 1-butyl-2,3-dimethylimidazolium tetrafluoroborate (alkylimidazolium tetrafluoroborate), and the sealing force is strong (800r / min) at 50°C Stir for 8 hours, wash and filter with absolute ethanol and acetone three times, dry at 60° C. for 12 hours, and calcined at 120° C. for 6 hours to obtain the fluorine-based ionic liquid surface-modified ternary cathode material of the present invention. After being modified by the fluorine-based ionic liquid, its microscopic morphology is still maintained and the crystal structure does not change (relevant morphology and crystal structure can refer to the corresponding drawings in Example 1, see figure 1 , figure 2 and image 3 ). The LiNi modified by fluorine-based ionic liquid 0.8 co 0.1 mn 0.1 o 2 The positive electrode material (NCM@LiF) was assembled into a battery, and at 2.8-4.3V, 0.1C rate, it...

Embodiment 3

[0031] Weigh 1.0g LiNi 0.3 co 0.2 mn 0.5 o 2 The material was dispersed into 5 g of ionic liquid N-alkylpyridine tetrafluoroborate, sealed and vigorously stirred (280 r / min) at room temperature for 12 h, then washed and filtered with absolute ethanol three times, and dried at 80° C. for 12 h. After calcining at 250° C. for 15 hours, the fluorine-based ionic liquid surface-modified ternary cathode material of the present invention is obtained. After being modified by the fluorine-based ionic liquid, its microscopic morphology is still maintained and the crystal structure does not change (relevant morphology and crystal structure can refer to the corresponding drawings in Example 1, see figure 1 , figure 2 and image 3 ). The LiNi modified by fluorine-based ionic liquid 0.3 co 0.2 mn 0.5 o 2 The positive electrode material is assembled into a battery. At 2.8-4.3V, 2C rate, its discharge specific capacity is 158.7mAh / g, and after 100 cycles, its discharge specific capa...

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Abstract

The invention discloses a method for surface modification of a ternary cathode material for lithium ion batteries by fluorine-based ionic liquid, which comprises the following steps: (1) a ternary cathode material is added into fluorine-based ionic liquid, which includes alkyl imidazole tetrafluoroborate, 1-ethyl acetate-3-methylimidazole tetrafluoroborate, and the like; and (2) stirring, filtering, washing, drying and calcining are carried out. The fluorine-based ionic liquid can interact with the lithium residue on the surface of the ternary cathode material through hydrolysis and form a lithium fluoride coating on the surface. The coating not only can reduce the side reaction between interfaces, but also can solve the problem that the ternary cathode material is sensitive to carbon dioxide/water in air and greatly improve the cycle life and rate performance of the material. The preparation method of the invention is simple, green and environment-friendly, can significantly improve the electrochemical performance of the material, and has a broad application prospect.

Description

technical field [0001] The invention is applied in the fields of lithium ion battery cathode materials and electrochemistry, and relates to a method for modifying the surface of a lithium ion battery ternary cathode material with a fluorine-based ionic liquid. Background technique [0002] Since the second industrial revolution, the environmental pollution and energy crisis brought about by the unprecedented development of human material civilization have become the key factors restricting the harmonious development of the world today. In order to ensure global sustainable development, we must vigorously develop renewable clean energy. With the investment of a large amount of manpower and material resources in the past ten years, although energy sources that are variable in time and diffusible in space, such as solar energy, wind energy, and tidal energy, nuclear energy that is difficult to deal with radioactive waste and has potential safety hazards, and geothermal energy t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/58H01M4/485H01M4/525H01M4/505H01M10/0525
CPCH01M4/366H01M4/485H01M4/505H01M4/525H01M4/582H01M10/0525Y02E60/10
Inventor 熊训辉王钢罗煜翔范梦娜林志华杨成浩
Owner SOUTH CHINA UNIV OF TECH
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