Lithium metal composite negative electrode with lithium-philic and lithium-phobic gradient structure, and preparation method thereof

A gradient structure, lithium metal technology, applied in negative electrodes, structural parts, battery electrodes, etc., can solve problems such as low Coulombic efficiency, affecting battery cycle efficiency, pulverization, etc., to improve Coulombic efficiency, improve cycle stability, ease The effect of electrode pulverization

Active Publication Date: 2020-08-28
SUN YAT SEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The specific problems include: 1) Lithium metal is in direct contact with the electrolyte, which is prone to some complex side reactions, which increases the interface impedance of the battery and affects the cycle efficiency of the battery; 2) Lithium ions cannot be deposited uniformly and densely during the cycle 3) The repeated rupture and regeneration of the unstable SEI film formed on the surface of the lithium negative electrode will continue to consume the electrolyte, resulting in a decrease in low Coulombic efficiency and irreversible capacity fading; 4) The generation of lithium dendrites will pierce the separator, resulting in battery short circuit and safety hazards

Method used

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  • Lithium metal composite negative electrode with lithium-philic and lithium-phobic gradient structure, and preparation method thereof
  • Lithium metal composite negative electrode with lithium-philic and lithium-phobic gradient structure, and preparation method thereof
  • Lithium metal composite negative electrode with lithium-philic and lithium-phobic gradient structure, and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] A kind of preparation method of cuprous sulfide-foam copper-lithium metal composite negative electrode through lithiophilic modification, comprises the following steps:

[0042] (1) Cut the commercial copper foam into a rectangular piece of 4cm*5 cm, soak it in absolute ethanol, and ultrasonicate for 15 minutes to remove the grease impurities on the surface; then, immerse the foam copper after the first cleaning in the pre-washed In the prepared 1 M dilute hydrochloric acid solution, ultrasonic for 15 minutes to remove surface oxides; finally, ultrasonic cleaning with water for 15 minutes to remove residual hydrochloric acid on the surface of foamed copper. Blow dry in a nitrogen atmosphere and set aside;

[0043] (2) Accurately weigh 0.0210 g of thioacetamide (TAA) and 0.0490 g of tin tetrachloride pentahydrate (SnCl4 ·5H 2 O) In a conical flask, measure 70.0mL of polyethylene glycol 400 (PEG400) in the conical flask, stir magnetically for 10 minutes, heat in an oil b...

Embodiment 2

[0046] In view of the fact that Example 1 compares the difference between modifying the lithiophilic layer and not modifying the lithiophilic layer on the same foamed copper matrix skeleton, this embodiment studies the two-dimensional matrix (cuprous sulfide-copper foil) skeleton and the three-dimensional matrix skeleton (sulfurized Cuprous - copper foam) for the difference in the negative electrode. The preparation method comprises the following steps:

[0047] (1) take the method same as embodiment 1 to clean copper foil and copper foam;

[0048] (2) Prepare the same precursor solution as in Example 1, and transfer the solution to a reaction kettle lined with polytetrafluoroethylene;

[0049] (3) Put the pretreated copper foam or copper foil vertically into the precursor solution, transfer it to a muffle furnace, heat it up to 180 °C at 10 °C / min, keep it for 15 h, and cool naturally to obtain the same lithium-ophilic modification Two-dimensional cuprous sulfide-copper foi...

Embodiment 3

[0053] In this embodiment, a three-dimensional porous matrix framework (foamed nickel), a lithium-philic layer (Ni 3 S 2 Nanosheet structure) and lithium-phobic layer (multi-walled carbon nanotubes) were combined to prepare a lithium-metal composite anode with a lithium-phobic gradient structure. Include the following steps:

[0054] (1) Cut the commercial nickel foam into rectangular pieces of 4cm*5 cm, soak in absolute ethanol, and ultrasonicate for 15 minutes to remove the grease impurities on the surface; then, immerse the foam nickel after the first cleaning in the pre-washed In the prepared 2 M dilute hydrochloric acid solution, sonicate for 15 minutes to remove surface oxides; finally, ultrasonically clean with water for 15 minutes to remove residual hydrochloric acid on the surface of foamed nickel. Transfer the cleaned foamed nickel to a watch glass and place it in a fume hood for 8 hours, let it dry naturally, and set aside;

[0055] (2) Weigh 0.63 g of Na 2 S 2...

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Abstract

The invention discloses a lithium metal composite negative electrode with a lithium-philic and lithium-phobic gradient structure, and a preparation method thereof. The lithium metal composite negativeelectrode is of a three-layer structure, wherein the bottom layer is a 3D porous matrix framework, the middle layer is a lithium-philic layer compounded on the 3D porous matrix framework, and the toplayer is a lithium-phobic layer compounded on the surface of the lithium-philic layer. The preparation method comprises the following steps: (1) preparing a 3D porous matrix skeleton, and cleaning; (2) transferring the 3D porous matrix skeleton to a prepared precursor solution; (3) forming a lithium-philic layer on the 3D porous matrix skeleton in situ by adopting a solvothermal method; (4) modifying a lithium-phobic layer on the lithium-philic layer; and (5) finally filling with lithium by adopting an electro-deposition method. According to the invention, the overpotential in the lithium metal nucleation and deposition process can be reduced by utilizing the lithium-philic layer, and the uniform deposition and dissolution of the lithium metal in the continuous cycle process are realizedby utilizing the characteristic that the lithium ion diffusion is promoted by utilizing the lithium-phobic layer, so that the growth of dendritic crystals is effectively avoided, and the cycle life ofthe lithium metal battery is greatly prolonged.

Description

technical field [0001] The invention belongs to the technical field of batteries, and in particular relates to a lithium metal composite negative electrode and a lithium metal battery with a lithium-affinity gradient structure. Background technique [0002] Among the existing commercial secondary batteries, lithium-ion batteries have been widely used in our lives due to their high energy density, good safety performance, long charge and discharge life, and low self-discharge, such as mobile phones, portable computers, Video cameras, electric vehicles, etc. However, with the continuous update of digital products and the vigorous development of electric vehicles, the requirements for battery capacity are getting higher and higher. However, most of the current commercial lithium-ion battery anode materials are carbon materials, making it difficult to increase the overall capacity of lithium-ion batteries. It is an inevitable development trend to choose anode materials with hig...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/134H01M4/1395H01M10/052
CPCH01M4/134H01M4/1395H01M10/052H01M2004/021H01M2004/027Y02E60/10
Inventor 韩东梅罗亚秋孟跃中肖敏王拴紧任山郭林莉
Owner SUN YAT SEN UNIV
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