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Interface protection film and a preparation method thereof, and application of interface protection film in lithium battery

A protective film, lithium battery technology, applied in the direction of lithium batteries, battery electrodes, non-aqueous electrolyte batteries, etc., can solve the problems of reducing battery cycle performance and safety, uneven deposition of lithium ions, and difficulty in large-scale application, etc. Improve cycle stability, reduce irreversible reactions, and promote the effect of industrialization

Active Publication Date: 2021-01-12
SVOLT ENERGY TECHNOLOGY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, the protective layer prepared by this liquid phase method is not uniform, and there are many impurities, which will increase the impedance of the entire battery, and the uneven protective layer will lead to uneven deposition of lithium ions, which is easy to form lithium dendrites and reduce the cycle of the battery. Performance and Security
Moreover, the above method is difficult to realize large-scale application in industry.

Method used

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  • Interface protection film and a preparation method thereof, and application of interface protection film in lithium battery
  • Interface protection film and a preparation method thereof, and application of interface protection film in lithium battery

Examples

Experimental program
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Embodiment 1

[0057] This embodiment provides an interface protective film and a preparation method thereof, the method comprising the following steps:

[0058] Add 9g of lithium fluoride (D50=0.933um) and 1g of polytetrafluoroethylene powder into the blender, stir at a low speed (100rpm) for 10 minutes, mix well, and then stir at a high speed (10000rpm) for 30 minutes to carry out the fiberization process . Put the mixed powder into a roller press, perform hot rolling at 150°C to form a film, fold and roll repeatedly, until the porosity of the interface protective film is 15%, and the thickness of the protective film is 20um.

[0059] In the interface protection film prepared in this example, the mass proportions of lithium fluoride and polytetrafluoroethylene were 90% and 10%, respectively.

[0060] This embodiment provides a negative electrode, which is prepared by hot-compressing the above-mentioned interface protection film onto a lithium foil.

Embodiment 2

[0062] This embodiment provides an interface protective film and a preparation method thereof, the method comprising the following steps:

[0063] Add 8g of lithium nitride (D50=1.095um) and 2g of polytetrafluoroethylene powder into the blender, stir at a low speed (200rpm) for 10 minutes, mix well, and then stir at a high speed (20000rpm) for 30 minutes to carry out the fiberization process . Put the mixed powder into a roller press, perform hot rolling at 150°C to form a film, and repeat the rolling until the porosity of the interface protective film is 13.9%, and the thickness of the protective film is 15um. Since lithium nitride is unstable, the whole process is completed under an inert gas atmosphere.

[0064] In the interface protection film prepared in this embodiment, the mass proportions of lithium nitride and polytetrafluoroethylene were 80% and 20%, respectively.

[0065] This embodiment provides a negative electrode, which is prepared by hot-compressing the above-m...

Embodiment 3

[0067] This embodiment provides an interface protective film and a preparation method thereof, the method comprising the following steps:

[0068] Put 2g of nano-silver powder (D50=236nm), 6g of carbon black (D50=1.573um), and 2g of polytetrafluoroethylene powder into the blender, stir at low speed (150rpm) for 10 minutes, mix well, and then high-speed (18000rpm) pulse Stir for 30 minutes to carry out the fibrillation process. The mixed powder was put into a roller press, hot rolled at 150°C to form a film, folded and rolled repeatedly, until the porosity of the interface protective film was 13.2%, and the thickness of the protective film was 15um.

[0069] In the interface protection film prepared in this example, the mass proportions of nano-silver, carbon black and polytetrafluoroethylene are 20%, 60% and 10%, respectively.

[0070] This embodiment provides a negative electrode, which is prepared by hot-compressing the above-mentioned interface protection film onto a lithi...

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Abstract

The invention discloses an interface protection film and a preparation method thereof, and application of the interface protection film in a lithium battery. The interface protection film comprises anetwork-shaped structure formed by mutually overlapping polymer fibers, and an inorganic additive dispersed and bonded in the network-shaped structure, wherein the inorganic additive can conduct lithium ions. The method comprises the following steps: (1) mixing fiberizable polymer powder, an inorganic additive and optional nanometer metal powder according to a formula ratio, and drawing the fiberizable polymer powder under the action of shearing force to form fibers so as to obtain a mixture; and 2) carrying out hot pressing treatment on the mixture until a preset thickness is reached so as toobtain the interface protection film. The interface protection film is applied to a lithium metal negative electrode; on one hand, lithium ions can be guided to be uniformly transmitted, so lithium is uniformly deposited in a charging and discharging process, and safety performance reduction caused by formation of irregular lithium dendrites in the deposition process is avoided; and on the otherhand, irreversible reaction between the metal lithium negative electrode and an organic electrolyte can be reduced.

Description

technical field [0001] The invention relates to the technical field of batteries, and relates to an interface protection film, a preparation method thereof and an application in lithium batteries, in particular to an interface protection film, a preparation method thereof, a negative electrode and a lithium battery. Background technique [0002] With the rapid development of consumer electronics and electric vehicles, the demand for energy density, safety, reliability and service life of batteries continues to soar. Lithium metal has a very high theoretical specific capacity (3860mAh / g) and the lowest potential (-3.04V), so lithium metal secondary batteries are the preferred system for the next generation of high energy density energy storage devices. [0003] However, lithium metal anodes are prone to irreversible reactions with organic electrolytes to form solid electrolyte interfacial films (SEI films), resulting in capacity loss. Moreover, irregular lithium dendrites ar...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J5/18C08L27/18C08K3/16C08K3/28C08K3/08C08K3/04H01M4/134H01M4/62H01M10/052
CPCC08J5/18H01M4/628H01M4/134H01M10/052C08J2327/18C08K3/16C08K2003/0806C08K3/04C08K2201/001C08K2201/003C08K3/28Y02E60/10
Inventor 马忠龙郑晓醒秦士林赵晓宁
Owner SVOLT ENERGY TECHNOLOGY CO LTD