Positive pole piece, preparation method thereof and lithium ion battery

A technology of positive electrode sheet and conductive agent, applied in the field of positive electrode sheet and its preparation, can solve problems such as restricting the development of lithium ion batteries, and achieve the effect of improving specific capacity and cycle stability, high capacity advantage, and improving cycle stability

Pending Publication Date: 2021-07-13
SUNWODA ELECTRIC VEHICLE BATTERY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These various unfavorable factors have greatly limited the development of lithium-ion batteries based on high-nickel cathodes.

Method used

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  • Positive pole piece, preparation method thereof and lithium ion battery
  • Positive pole piece, preparation method thereof and lithium ion battery

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Experimental program
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Effect test

preparation example Construction

[0055] In the second aspect of this application, the preparation method of the positive electrode sheet is provided, including the following steps:

[0056] S1: The polycrystalline active material, the first adhesive, and the first conductive agent are dissolved in the first solvent, and mixed uniform mixed by stirring to obtain a first slurry;

[0057] S2: The polycrystalline active material, the single crystal active material is dissolved in the second solvent, and mixed with stirring is mixed, and the second slurry is obtained;

[0058] S3: The single crystal active material, the second adhesive, and the second conductive agent are dissolved in the third solvent, mixed uniform mixed by stirring, to obtain a third slurry;

[0059] S4: Apply the first slurry obtained by step S1 to the surface of the current collector, forming the first material layer, applying the second slurry material obtained in step S2 to the outer surface of the first material layer, forming a transition lay...

Embodiment 1

[0072] (1) Preparation of the positive electrode plate

[0073] S1: Polycrystalline active material lini 0.8 CO 0.1 Mn 0.1 O 2 The first binder PVDF and the first conductive agent acetyxyn black are dissolved in N-methylpyrrolidone according to the mass of 97: 1: 2, and mixed with N-methylpyrrolidone, and mixed with a solid content of 40%;

[0074] S2: Polycrystalline active material lini 0.8 CO 0.1 Mn 0.1 O 2 , Single crystal active material Lini 0.8 CO 0.1 Mn 0.1 O 2 According to the volume of 1: 1 is soluble in N-methylpyrrolidone, it is mixed and mixed, and the second slurry is obtained;

[0075] S3: Lini of single crystal active materials 0.9 CO 0.05 Mn 0.05 O 2 The second adhesive PVDF and the second conductive agent acetylene black, carbon nanotubes are well dissolved in N-methylpyrrolidone according to 96.5: 1: 1.5: 1, and mixed with N-methylpyrrolidone, mixed with mixing, 50% solid content of 40%. Third slurry;

[0076] S4: The first slurry obtained by step S1 is applied ...

Embodiment 2

[0082] Based on Example 1, the difference is only: in Example 2, the polycrystalline active material Lini 0.8 CO 0.1 Mn 0.1 O 2 The mass ratio of the first binder PVDF and the first conductive agent acetylene is 96: 1: 3.

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Abstract

The invention discloses a positive pole piece, a preparation method thereof and a lithium ion battery. The positive pole piece comprises a current collector, a first material layer coated on the current collector, a transition layer coated on the first material layer, and a second material layer coated on the transition layer, the first material layer comprises a polycrystalline active material, the second material layer comprises a single crystal active material, and the transition layer is a mixed layer of a single crystal active material and a polycrystal active material. The cycle performance, the energy density and the dynamic performance of the battery are improved through the synergistic effect of the first material layer, the second material layer and the transition layer.

Description

Technical field [0001] The present application relates to the field of lithium-ion battery, and in particular, a positive electrode plate and a preparation method thereof, a lithium ion battery. Background technique [0002] With the development of electric vehicles, consumers and downstream cars have put forward higher requirements for the battery life of electric vehicles. Based on this objective fact, lithium-ion batteries equipped with high nickel positive are more favored. Because by increasing the ratio of nickel in the layered material, the specific capacity of the battery can be improved, thereby increasing its energy density. However, while increasing the energy density of the battery, the cycle stability of the high nickel positive is also sacrificed. On the one hand, the high-cost nickel has strong oxidation resistance. It is not friendly for a carbonate solvent with a weak antioxidant capacity, and the side effect of the electrode interface will generate a thicker int...

Claims

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Application Information

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IPC IPC(8): H01M4/66H01M4/04H01M10/0525
CPCH01M4/667H01M4/0404H01M10/0525Y02E60/10
Inventor居小康张友为胡梦张耀
OwnerSUNWODA ELECTRIC VEHICLE BATTERY CO LTD