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Composite negative pole piece, preparation method thereof and lithium ion battery

A technology of negative pole piece and composite substrate, applied in the direction of negative electrode, battery electrode, secondary battery, etc., can solve the problems of poor integrity and compatibility, deterioration of full battery cycle, weakening the advantages of lithium metal, etc., and achieve cycle life. Increase, is conducive to stable and uniform deposition, improve the effect of cycle stability

Active Publication Date: 2020-11-06
ZHUHAI COSMX BATTERY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

First, during the cycle, due to the local polarization caused by the uneven deposition of lithium ions on the surface of lithium metal, lithium dendrites grow on the surface of lithium metal, and when the lithium dendrites grow to a certain extent, they may penetrate the separator. , leading to a short circuit in the battery, which raises safety concerns
Second, if lithium dendrites break, "dead lithium" will form, resulting in a loss of battery capacity
Third, on the road to industrial application, the mechanical properties of traditional lithium metal negative electrodes are poor, which is not conducive to the welding of tabs and the assembly of large batteries
However, the three-dimensional carrier materials in the prior art often have a large self-weight (such as porous copper foil, copper foam, nickel foam, etc.), which greatly increases the weight of the electrode, thus weakening the advantages of lithium metal as a high specific capacity electrode material.
Secondly, due to the active nature of lithium metal, it is very easy to have side reactions with the electrolyte, which leads to the deterioration of the integrity and compatibility of the system, thereby deteriorating the cycle of the full battery.

Method used

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  • Composite negative pole piece, preparation method thereof and lithium ion battery
  • Composite negative pole piece, preparation method thereof and lithium ion battery
  • Composite negative pole piece, preparation method thereof and lithium ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0053] Embodiment 1 proposes a kind of composite negative pole sheet and lithium ion battery, and its preparation method comprises the following steps:

[0054] 1. Preparation of composite negative electrode sheet

[0055] (1) Mix carbon fibers, PLA, surfactants, and toughening compatibilizers in a mass ratio of 5.3:1.8:0.2:0.1 and place them in a beaker, add a certain amount of chloroform, Stir evenly at a speed of 500rpm for 3 hours to form a homogeneous solution. After the stirring is completed, the slurry is fully volatilized to obtain a block-shaped solid, vacuum-dried at 50°C for 12 hours, and sheared and ground to obtain a granular 3D printing material precursor. body.

[0056] (2) Shear and grind the precursor of the granular 3D printing material and send it into the screw extruder for blending and silk making. The diameter of the wire is 0.40 mm, and the wire is coiled.

[0057] (3) Cold-press metal lithium foil and Cu current collector into a Li-Cu layered structu...

Embodiment 2

[0065] Embodiment 2 proposes a kind of composite negative pole sheet and soft pack polymer lithium ion battery, and its preparation method comprises the following steps:

[0066] 1. Preparation of composite negative electrode sheet

[0067] (1) Mix carbon fiber, polycaprolactone (PCL) and surfactant according to the mass ratio of 6:1.8:0.1 and put them in a beaker. Stir at a uniform speed for 3 hours to form a homogeneous solution. After the stirring is completed, the slurry is fully volatilized to obtain a block-shaped solid, vacuum-dried at 59°C for 18 hours, and sheared and ground to obtain a granular 3D printing material precursor.

[0068] (2) The precursor of the granular 3D printing material is sheared and ground and sent to the screw extruder for blending and silk making. The silk making temperature is 73°C, and it is pulled by a tractor at a speed of 22cm / min, and extruded The diameter of the wire is 0.80 mm, and the wire is coiled.

[0069] (3) Metal lithium foil a...

Embodiment 3

[0077] Embodiment 3 proposes a composite negative pole piece and an all-solid-state abrasive lithium-ion battery, and its preparation method comprises the following steps:

[0078] 1. Preparation of composite negative electrode sheet

[0079] (1) Mix carbon fiber, acrylonitrile-butadiene-styrene plastic (ABS), surfactant, and toughening compatibilizer according to the ratio of 5.1:1.3:0.15:0.05 by mass and put them in a beaker. Add a certain amount of dichloromethane, and stir evenly at room temperature at a speed of 800rpm for 6h to form a homogeneous solution. After the stirring is completed, the slurry is fully volatilized to obtain a block-shaped solid, vacuum-dried at 50°C for 11h, and Granular 3D printing material precursors were obtained after shearing and grinding.

[0080] (2) The precursor of the granular 3D printing material is sheared and ground and sent to the screw extruder for blending and silk making. The silk making temperature is 226°C, and it is pulled by a...

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Abstract

The invention relates to a composite negative pole piece, a preparation method thereof and a lithium ion battery. The negative pole piece comprises a current collector metal-metal lithium composite substrate and a carbon fiber-lithium-containing metal composite structure arranged on the current collector metal-metal lithium composite substrate. The carbon fiber-lithium-containing metal composite structure comprises a three-dimensional skeleton and lithium-containing metal, wherein the mass ratio of the three-dimensional skeleton to the lithium-containing metal is (1-18): 6. Gaps of the skeleton are filled with the lithium-containing metal. The three-dimensional skeleton comprises carbon fiber, a polymer, a surfactant and a toughening agent in a mass ratio of (60-80): (10-30): (1-5): (0-5).According to the composite negative pole piece, a three-dimensional skeleton is filled with metal lithium, the composite negative pole piece with light weight and high strength is obtained, stable and uniform deposition of metal lithium is facilitated under high current density, the integrity and uniformity of an SEI film are improved, the conditions of pulverization and lithium death of a lithium piece are improved, the growth of lithium dendrites can be inhibited to a certain extent, and meanwhile, the composite negative pole piece has good interface performance with an electrolyte.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a composite negative pole piece, a preparation method thereof and a lithium ion battery. Background technique [0002] In recent years, with the rapid development of electric vehicles and high-end portable electronic devices, people's requirements for battery energy density continue to increase. At present, the industrialized lithium-ion batteries with graphite as the negative electrode have been difficult to meet the increasing demand for specific energy, so Lithium metal anodes with high specific capacity have entered the field of vision of researchers. Lithium metal has a specific capacity of 3860mAh / g and an electrochemical potential of -3.04V (vs the standard hydrogen electrode), making it an ideal anode material for lithium batteries. To use lithium metal as an anode material for lithium-ion batteries, we still need to overcome the following diffi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/134H01M4/1395H01M4/38H01M4/62H01M10/0525
CPCH01M4/134H01M4/1395H01M4/382H01M4/625H01M4/628H01M10/0525H01M2004/027Y02E60/10
Inventor 张赵帅赵伟李素丽李俊义徐延铭
Owner ZHUHAI COSMX BATTERY CO LTD
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