Negative electrode and lithium secondary battery comprising same

A negative electrode and negative electrode active material technology, applied in the direction of secondary batteries, lithium batteries, negative electrodes, etc., can solve the problems of solid-electrolyte interphase instability, poor cycle performance, phosphorus use restrictions, etc., to achieve excellent fast charging characteristics and Effects of lifetime, high energy density, and excellent Li+ conductivity

Pending Publication Date: 2021-05-28
TIANJIN ENERGIES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But the atomic reorganization near the zigzag diffusion channels of phosphorus nanoflakes hinders Li + Kinetics of transfer across the surface
In addition, the volume change of phosphorus during the charge-discharge cycle destabilizes the solid-electrolyte interphase (SEI), resulting in poor cycle performance
Therefore, the use of phosphorus in lithium secondary batteries is limited

Method used

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  • Negative electrode and lithium secondary battery comprising same
  • Negative electrode and lithium secondary battery comprising same
  • Negative electrode and lithium secondary battery comprising same

Examples

Experimental program
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Effect test

preparation example Construction

[0038] The preparation method of the phosphorus-carbon composite with an organic coating on the surface: (1) A certain proportion of bulk phosphorus and carbon mixture is ball-milled with a planetary ball mill, and the revolution speed is 50-300 / min. The rotation speed is 100-500r / min, and the ball milling time is 8-48h to form a phosphorus-carbon compound; (2) In a vacuum glove box, add the organic matter that forms the organic coating into the ball mill tank containing the phosphorus-carbon compound, and ball mill again , the revolution speed is 10-100r / min, the rotation is 50-200r / min, and the ball milling time is 2-6h, forming a phosphorus-carbon composite with an organic coating on the surface.

[0039] In addition, the mass ratio of the first negative electrode active material layer to the second negative electrode active material layer is less than or equal to 1:1, that is, the layer density of the second negative electrode active material is higher than the first negati...

Embodiment 1

[0056] The mixture of artificial graphite and natural graphite as the weight ratio of negative active material of 80:20, the SBR as binder, the CMC as thickener and the carbon black as conductive material are 95.4:2.3 by weight: 1.3:1.0 in a weight ratio, and water was added thereto as a solvent to prepare the first negative electrode slurry. The mixture of artificial graphite and black phosphorus as the weight ratio of the negative electrode active material of 20:80, the SBR as the binding agent, the CMC as the thickener and the carbon black as the conductive material are 95.5:2.3 by weight: Mixed at a weight ratio of 1.3:1.0, wherein based on the weight of the phosphorus-carbon composite, the surface contained 10% polyaniline, and water was added thereto as a solvent to prepare the second negative electrode slurry. The first negative electrode slurry and the second negative electrode slurry were applied to a copper foil having a thickness of 8 μm at a weight ratio of 1:1. D...

Embodiment 2

[0060] Embodiment 2: Changing the ratio of negative electrode active material black phosphorus and graphite in the second negative electrode active material layer

[0061] The negative electrode was prepared in the same manner as in Example 1, except that a mixture of artificial graphite and azurite phosphorus with a weight ratio of 10:90 was used as the negative active material of the second negative electrode slurry.

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Abstract

The invention provides a negative electrode and a lithium secondary battery comprising the same. The negative electrode comprises a current collector, a first negative electrode active material layer and a second negative electrode active material layer, wherein the first negative electrode active material layer is formed on at least one surface of the current collector, and comprises a mixture of natural graphite and artificial graphite as a negative electrode active material and a first adhesive; and the second negative electrode active material layer is formed on the first negative electrode active material layer and includes a phosphorus-carbon composite as a negative electrode active material and a second binder. According to the invention, the phosphorus-carbon compound which has high energy density and excellent Li<+> conductivity and contains an organic coating on the surface is used as the negative electrode material, and the lithium ion secondary battery with high energy density, fast charge characteristic and excellent service life can be prepared by adopting the design of a double-layer negative electrode structure.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, in particular to a negative electrode and a lithium secondary battery containing the negative electrode. Background technique [0002] Generally, a secondary battery consists of a positive electrode, a negative electrode, an electrolyte, and a separator. In the secondary battery, energy transfer occurs while lithium ions reciprocate between opposite electrodes, so that by the first charge, lithium ions from the positive electrode active material are intercalated in the negative electrode active material such as carbon particles, and after discharge Lithium ions are deintercalated during this time, and in this way, the secondary battery can be charged and discharged. [0003] As lithium secondary batteries are more and more widely used in the power vehicle industry, there are higher requirements for high energy density, long cycle life and high rate charge and discharge performance of lithium...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/13H01M4/133H01M4/62H01M10/052H01M10/0525
CPCH01M4/13H01M4/133H01M4/628H01M10/052H01M10/0525H01M2004/021H01M2004/027Y02E60/10
Inventor 王俊姿邓海福李兴旺李文文
Owner TIANJIN ENERGIES
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