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Negative pole piece, preparation method thereof and electrochemical device

A negative electrode sheet and negative electrode technology, applied in the direction of electrochemical generators, negative electrodes, electrode manufacturing, etc., can solve the problems of increasing the irreversible capacity of electrochemical devices, deteriorating the safety performance of electrochemical devices, short-circuiting electrochemical devices, etc., achieving excellent Safety performance and cycle performance, improvement of kinetic performance, and effect of suppressing gas production

Active Publication Date: 2020-01-07
CONTEMPORARY AMPEREX TECH CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, during the circulation process of the existing electrochemical devices, there are many side reactions between the interface between the electrolyte and the negative electrode, which causes the electrolyte to decompose and produce gas, which deteriorates the safety performance of the electrochemical device. At the same time, the electrolyte cations on the negative electrode are continuously consumed. The irreversible capacity of the device continues to increase, resulting in a rapid decline in its cycle life
Moreover, due to the poor transport performance of electrolyte cations at the negative electrode, it will also lead to the formation of metal dendrites at the negative electrode interface, which is prone to short circuits in the electrochemical device and further deteriorates the safety performance of the electrochemical device.

Method used

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  • Negative pole piece, preparation method thereof and electrochemical device
  • Negative pole piece, preparation method thereof and electrochemical device
  • Negative pole piece, preparation method thereof and electrochemical device

Examples

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Effect test

preparation example Construction

[0058] The embodiment of the present invention also provides a method for preparing the negative electrode sheet 10, the method comprising the following steps:

[0059] Step S100, disposing a negative electrode active material layer on at least one surface of the negative electrode current collector.

[0060] Step S100 can be implemented in any of the following ways:

[0061]Negative electrode active material and optional binding agent and conductive agent are dispersed in solvent, and solvent can be deionized water or N-methylpyrrolidone (NMP) for example, forms uniform negative electrode slurry; Negative electrode slurry is coated or It is sprayed on the surface of the negative electrode collector, and after drying and other processes, a negative electrode active material layer is prepared on at least one surface of the negative electrode collector.

[0062] The negative electrode active material is directly prepared on the negative electrode current collector to obtain a n...

Embodiment 1

[0107] Preparation of negative electrode sheet

[0108] Step S110, mix the negative electrode active material, the conductive agent acetylene black, the binder styrene-butadiene rubber (SBR), and the thickener sodium carboxymethylcellulose (CMC) according to the weight ratio of 96:1:2:1, and add a solvent to remove Ionized water, stirred and mixed evenly to obtain negative electrode slurry. Wherein the negative electrode active material is artificial graphite.

[0109] Step S120 , uniformly coating the negative electrode slurry on both surfaces of the negative electrode current collector copper foil, drying at 80° C. to 90° C. after coating, and then cold pressing to obtain a negative electrode active material coating.

[0110] Step S200 , using a plasma-assisted electron beam evaporation method to prepare an inorganic dielectric layer on the surface of the negative electrode active material coating. Specifically include:

[0111] Step S210', vacuumize the reaction chambe...

Embodiment 2~7

[0122] The difference from Example 1 is that the relevant parameters in the preparation steps of the negative electrode sheet are adjusted.

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Abstract

The invention discloses a negative pole piece, a preparation method thereof and an electrochemical device. The negative pole piece comprises a negative pole current collector, a negative pole active material layer and an inorganic dielectric layer which are stacked; the negative pole active material layer comprises a first surface and a second surface which are opposite to each other, wherein thefirst surface is far away from the negative pole current collector; the inorganic dielectric layer is arranged on the first surface of the negative pole active material layer; the inorganic dielectriclayer is composed of an inorganic dielectric material; the inorganic dielectric layer comprises a first dielectric layer located on the outer surface of the negative pole active material layer; the thickness of the first dielectric layer is 30-1000 nm; the compaction density of the negative pole piece is 1.2 g / cm <3>-2.0 g / cm<3>; the porosity of the negative pole piece is 25%-45%; and the electrolyte infiltration rate of every 10cm*10cm area of the negative pole piece is greater than or equal to 2 microgram / s. The negative pole piece provided by the invention is used for an electrochemical device, so that the electrochemical device has excellent safety performance and high cycle performance at the same time.

Description

technical field [0001] The invention belongs to the technical field of energy storage devices, and in particular relates to a negative pole piece, a preparation method thereof and an electrochemical device. Background technique [0002] Electrochemical devices can convert chemical energy into electrical energy, have stable voltage and current, reliable performance, simple structure, and easy to carry. They have become the main power source of various consumer electronics and electric products, and are widely used in people's production and every aspect of life. In recent years, the market has put forward higher and higher requirements for the cycle performance and safety performance of electrochemical devices. [0003] However, during the circulation process of the existing electrochemical devices, there are many side reactions between the interface between the electrolyte and the negative electrode, which causes the electrolyte to decompose and produce gas, which deteriora...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/02H01M4/04
CPCH01M4/02H01M4/0404H01M2004/027H01M2004/021H01M4/587H01M4/133H01M10/0525H01M4/043H01M2004/8684Y02E60/50Y02E60/10C23C14/0021C23C14/081C23C14/30H01M4/0423H01M4/1393H01M4/628
Inventor 李铖盛长亮黄华锋黄起森
Owner CONTEMPORARY AMPEREX TECH CO
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