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Method of forming negative electrode protective layer through in-situ transfer

A protective layer and negative electrode technology, which is applied in the electrochemical treatment of electrodes, electrode manufacturing, battery electrodes, etc., can solve the problems of increasing difficulty, reducing battery cycle performance, and reducing the influence of protective layers, so as to reduce interface impedance and reduce preparation. The effect of cost, preparation difficulty and loose preparation conditions

Active Publication Date: 2020-09-22
BEIJING NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Among them, since the negative pole piece, especially the lithium metal pole piece, is very active and easily reacts with water and oxygen, the experimental conditions need to be strictly controlled in the process of modifying the negative pole, which will increase the difficulty of wide application of the corresponding method.
In addition, the increased interfacial internal resistance between the protective layer and the negative electrode is usually a concern of researchers. If the two cannot be effectively contacted, the influence of the protective layer on the lithium ion deposition behavior may be reduced, and the additional interfacial internal resistance It will also reduce the cycle performance of the battery

Method used

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  • Method of forming negative electrode protective layer through in-situ transfer
  • Method of forming negative electrode protective layer through in-situ transfer

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preparation example Construction

[0040] The preparation method of the present invention will be further described in detail in conjunction with specific examples below. It should be understood that the following examples are only for illustrating and explaining the present invention, and should not be construed as limiting the protection scope of the present invention. All technologies realized based on the above contents of the present invention are covered within the scope of protection intended by the present invention.

[0041] The experimental methods used in the following examples are conventional methods unless otherwise specified; the reagents and materials used in the following examples can be obtained from commercial sources unless otherwise specified.

[0042] In this embodiment, when the prepared lithium-ion battery is subjected to a cycle charge-discharge test, the lithium-ion battery is subjected to a charge-discharge cycle test at 0.5C, and the 10th cycle, the 100th cycle, the 200th cycle and t...

Embodiment 1

[0047] Step 1) Dissolve 25 g of sodium dodecylbenzenesulfonate in 460 mL of water to obtain a mixed system, then disperse 160 g of nickel oxide in the above mixed system, add 5 g of styrene-butadiene rubber binder, and stir thoroughly to prepare a mixed slurry ;

[0048] Step 2) applying the mixed slurry scraper of step 1) to one side of the polypropylene diaphragm base layer;

[0049] Step 3) Dry the base layer of the diaphragm coated with the mixed slurry in step 2) in a vacuum oven at 40° C. for 2 hours to prepare the diaphragm with the nickel oxide coating; the thickness of the coating is 4 μm.

[0050] Step 4) Assemble the Li-ion battery:

[0051] Put the nickel oxide diaphragm obtained in step 3) between the positive electrode and the negative electrode sheet, orient the coating direction toward the negative electrode side, add 100 μL of commercial lithium-ion battery electrolyte, put the reed and seal it with a hydraulic sealing machine to prepare a button type 2032 L...

Embodiment 2

[0056] Other steps are with embodiment 1, and difference is only in:

[0057] Step 1) dissolving 15 g of methyl amyl alcohol in 1500 mL of water to obtain a mixed system, then dissolving 145 g of iron phosphate in the above mixed system, adding 14 g of polyacrylic acid binder and fully stirring to obtain a composite slurry;

[0058] Step 5) Coating in-situ transfer process: energize at a constant voltage of 1.5V for 10 hours. During the energization process, lithium ions are embedded in the iron phosphate lattice and form compounds such as lithium iron phosphate, which can form a uniform layer and be closely connected with the negative electrode. Combined, that is, a protective layer is formed on the surface of the negative electrode.

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Abstract

The invention provides a method for forming a negative electrode protective layer through in-situ transfer, and the method comprises the following steps: coating an initial raw material of a negativeelectrode protective layer on a diaphragm as a coating, and after a battery is assembled, transferring the coating on the diaphragm to the surface of a negative electrode of a lithium ion battery through reaction to form the protective layer, wherein the initial raw materials form a coating on the diaphragm, the preparation process is simple, and the preparation conditions are loose. The reactionoccurs in the battery, and is transferred to the surface of the negative electrode through the reaction without additionally controlling water oxygen conditions. The protective layer and the surface of the negative electrode form a whole due to reaction, the interface impedance between the protective layer and the negative electrode is reduced, and the cycle life of the corresponding battery is prolonged. The protective layer can effectively influence the lithium deposition behavior in the cycle process on the surface of the negative electrode, and is beneficial to improving the stability of the corresponding negative electrode and the safety of the battery.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a method for forming a negative electrode protection layer through in-situ transfer. Background technique [0002] Lithium-ion batteries have many advantages such as high specific capacity, long cycle life, and environmental protection. They are one of the main representatives of high-performance secondary batteries. They have been widely used in various electronic devices, electric or hybrid vehicles, and aerospace. different area. Among them, lithium-ion batteries are mainly composed of four parts: positive electrode, negative electrode, separator and electrolyte. At present, carbon negative electrode is mostly used as negative electrode material, and its theoretical specific capacity is relatively low (372mAh / g), which is difficult to meet the growing demand. Therefore, new negative electrode materials such as silicon carbon electrodes and lithium me...

Claims

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Application Information

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IPC IPC(8): H01M10/058H01M10/0525H01M4/1395H01M4/04H01M2/14H01M2/16
CPCH01M10/058H01M10/0525H01M4/1395H01M4/0438Y02E60/10Y02P70/50
Inventor 周建军胡志宇刘凤泉李林
Owner BEIJING NORMAL UNIVERSITY