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Battery negative electrode sheet, preparation method thereof, and lithium ion battery

A battery negative electrode and negative electrode technology, applied in battery electrodes, electrode manufacturing, electrode collector coating, etc., can solve the problem of unsatisfactory first-time coulombic efficiency cycle performance of lithium ions, inability to meet the change of silicon volume, and strong brittleness of the binder and other problems, to achieve good electrolyte infiltration and adsorption performance, avoid adverse effects, and good film-forming effect

Active Publication Date: 2021-05-04
SOUTH UNIVERSITY OF SCIENCE AND TECHNOLOGY OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] In view of the existing silicon-based lithium-ion batteries, the binder is brittle, easy to crack, and cannot meet the volume change of silicon during charging and discharging, which leads to the unsatisfactory first-time Coulombic efficiency and cycle performance of the obtained lithium-ion. The invention provides a battery negative electrode sheet and a preparation method thereof

Method used

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  • Battery negative electrode sheet, preparation method thereof, and lithium ion battery
  • Battery negative electrode sheet, preparation method thereof, and lithium ion battery
  • Battery negative electrode sheet, preparation method thereof, and lithium ion battery

Examples

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preparation example Construction

[0064] In one embodiment, the method for preparing the negative electrode sheet of the battery at least includes the following steps:

[0065] Step S01. Weigh the silicon material, conductive agent and binder according to the formula of the above-mentioned battery negative plate;

[0066] Step S02. Performing ball milling on the weighed silicon material and conductive agent to obtain a first mixed material;

[0067] Step S03. Mixing the first mixed material with the weighed binder and an appropriate amount of solvent to obtain negative electrode slurry;

[0068] Step S04. Coating the negative electrode slurry on the surface of the negative electrode current collector, and subjecting the negative electrode current collector coated with the negative electrode slurry to a first drying treatment, a tableting treatment, and a second drying treatment.

[0069]Specifically, in the above step S01, the formula of the negative electrode sheet of the battery is as described above, so it...

Embodiment 1

[0084] A battery negative electrode sheet, comprising copper foil and a negative electrode material layer attached to the surface of the copper foil, the material of the negative electrode material layer includes silicon material, a conductive agent, and a binder. Wherein, the silicon material is nano-scale silicon powder, the particle size is 20nm-60nm, the average particle size is 40nm, the conductive agent is carbon black conductive agent (Super P), and the binder is calcium lignosulfonate; In addition, the mass ratio of the negative electrode material in the negative electrode material layer is silicon material: conductive agent: binder = 3:1:1.

Embodiment 2

[0086] A battery negative electrode sheet, comprising copper foil and a negative electrode material layer attached to the surface of the copper foil, the material of the negative electrode material layer includes silicon material, a conductive agent, and a binder. Wherein, the silicon material is nano-scale silicon powder, the particle size is 30nm-50nm, the average particle size is 40nm, the conductive agent is carbon black conductive agent (Super P), and the binder is calcium lignosulfonate; In addition, the mass ratio of the negative electrode material in the negative electrode material layer is silicon material: conductive agent: binder = 7:2:2.

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Abstract

The invention relates to the technical field of lithium-ion batteries, and specifically provides a battery negative electrode sheet, a preparation method thereof, and a lithium-ion battery. The negative electrode sheet of the battery includes a negative electrode current collector and a negative electrode material layer attached to the surface of the negative electrode current collector. The material forming the negative electrode material layer includes a silicon material, a conductive agent, and a binder. The material forming the negative electrode material layer Among them, according to the mass ratio, the silicon material: conductive agent: binder = (5-10): (1-3): (1-3); the binder is a product of lignin cross-linking modification . The negative electrode sheet of the battery has excellent mechanical strength and mechanical compression resistance, and limits the silicon material to a certain area so that volume deformation occurs in a limited space, while preventing silicon particles from slipping or colliding with copper foil. This not only ensures the integrity of the electrode conductive network, but also maintains the mechanical integrity of the electrode, thereby greatly improving the electrochemical performance of the silicon negative electrode.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a battery negative plate, a preparation method thereof and a lithium ion battery. Background technique [0002] In recent years, developed countries in the world have invested heavily in the development of new energy electric vehicles to reduce CO 2 and other toxic and harmful gas emissions. In the research of electric vehicles, how to develop an energy storage device with high energy density and high power density has become a key point of technological breakthrough. [0003] In the past 50 years, due to the characteristics of high voltage, high specific energy, and good safety performance, lithium-ion batteries have become the focus of research on energy storage devices for electric vehicles. [0004] In lithium-ion battery technology, the negative electrode active material often used is graphite, but the theoretical specific capacity (372mAh / g) of g...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/62H01M4/134H01M4/1395H01M4/04H01M10/0525
CPCH01M4/0404H01M4/043H01M4/134H01M4/1395H01M4/621H01M10/0525H01M2220/20Y02E60/10
Inventor 邓永红朱庆卢周广石桥
Owner SOUTH UNIVERSITY OF SCIENCE AND TECHNOLOGY OF CHINA