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Negative electrode material and preparation method thereof, negative electrode plate and lithium ion battery

A technology of negative electrode material and negative electrode sheet, which is applied in the field of negative electrode sheet and lithium-ion battery, negative electrode material and its preparation, can solve the problems of reduced battery cycle performance and rate performance, reduced charge and discharge efficiency of electrode materials, and low strength of SEI film, etc. Achieve the effects of improving compatibility, improving lithium ion deintercalation rate, and improving the first charge and discharge efficiency

Inactive Publication Date: 2022-03-22
HUIZHOU LIWINON NEW ENERGY TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The formation of the SEI film will consume part of the lithium ions, which will increase the irreversible capacity of the entire battery and reduce the charge and discharge efficiency of the electrode material.
In addition, the SEI film on the graphite surface will be stretched by stress during the expansion and contraction of the graphite negative electrode, because the strength of the SEI film itself is not high, and the structure is destroyed during the deformation process; the direct contact between the electrolyte and the graphite at the gap causes the electrolyte to It is decomposed and consumed to form a new SEI film. During the charging and discharging process of the lithium-ion battery, the above process occurs repeatedly, resulting in the consumption of the electrolyte. In addition, the SEI film formed on the surface of the graphite accumulates thicker and thicker, and the surface impedance of the negative electrode increases, causing the entire battery to The cycle performance and rate performance are degraded

Method used

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  • Negative electrode material and preparation method thereof, negative electrode plate and lithium ion battery

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preparation example Construction

[0027] 1, a kind of preparation method of negative electrode material, LiPF 6 The powder and the graphite material are dissolved in the solvent, stirred and mixed, stirred and centrifuged, and calcined to obtain the negative electrode material.

[0028] The present invention adopts the method of in-situ coating, and utilizes the cheap LiPF 6 A layer of LiF is coated on the surface of the prepared graphite material. The LiF coating layer can improve the compatibility between the graphite negative electrode material and the electrolyte; in addition, LiF itself has high strength and can maintain its structural integrity during the expansion and contraction of the graphite negative electrode, which improves the cycle performance and rate performance of the graphite negative electrode. .

[0029] The invention has simple operation and simple required equipment. LiPF 6 The in-situ coating method can make the formed LiF layer and graphite more tightly combined, improve the compat...

Embodiment 1

[0051] Under an argon atmosphere, weigh 10g of graphite anode material and 0.608g of LiPF by electronic balance 6 Place in a beaker, and add 100mL of ethyl methyl carbonate to it, stir continuously to mix evenly; at a temperature of 50°C, stir magnetically for 100min; centrifuge the mixture in the above steps at 2000r / min, and remove the lower layer The precipitate was placed in a vacuum tube furnace, and calcined at 350°C for 4 hours under an argon atmosphere; finally, the high-energy ball milling method was used at 300r / min for 6 hours, and passed through a 250-mesh sieve to obtain a 1wt% LiF-coated graphite anode material.

Embodiment 2

[0053] Under an argon atmosphere, weigh 12g of graphite anode material and 0.8g of LiPF by electronic balance 6 Put it in a beaker, and add 100mL of ethyl methyl carbonate into it, stir continuously to mix evenly; at a temperature of 60°C, stir magnetically for 80min; centrifuge the mixture in the above steps at 1800r / min, and remove the lower layer The precipitate was placed in a vacuum tube furnace and calcined at 400°C for 5 hours under an argon atmosphere; finally, the high-energy ball milling method was used at 350r / min for 7 hours to pass through a 250-mesh sieve to obtain a 1wt% LiF-coated graphite anode material.

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Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a negative electrode material and a preparation method thereof, a negative plate and a lithium ion battery, LiPF6 powder and a graphite material are dissolved in a solvent in an inert gas environment, stirred and mixed, stirred and centrifuged, and calcined in the inert gas environment to obtain the negative electrode material. According to the preparation method of the negative electrode material, a LiPF6 in-situ coating method can enable a generated LiF layer to be combined with graphite more tightly, the problem that an SEI film is low in mechanical strength is solved, meanwhile, the compatibility of the graphite and the negative electrode material is improved, generation of the SEI film is reduced, and the first charge-discharge efficiency of the electrode material is improved; meanwhile, the lithium ion conductivity is relatively high, so that the lithium ion deintercalation rate on the surface of the graphite can be improved, and the cycle performance and the rate capability are improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a negative electrode material, a preparation method thereof, a negative electrode sheet and a lithium ion battery. Background technique [0002] In order to solve the increasingly severe environmental problems, the performance requirements of lithium-ion batteries are getting higher and higher. As the most widely used commercial lithium-ion battery anode material, graphite firmly controls the market advantage due to its high electronic conductivity, stable voltage platform, abundant resources, low price and many other advantages. However, graphite anode itself still has disadvantages such as low ionic conductivity and poor compatibility with electrolyte. [0003] During the first charging and discharging process of the lithium-ion battery, that is, before the lithium ions start to intercalate into the graphite electrode, the electrode material and the o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B32/205C01D15/04H01M4/13H01M4/36H01M4/58H01M10/0525
CPCC01B32/205C01D15/04H01M4/364H01M4/58H01M4/13H01M10/0525C01P2004/80C01P2006/40
Inventor 王震陈杰项海标
Owner HUIZHOU LIWINON NEW ENERGY TECH CO LTD