Sandwiched-structure composite metal lithium negative electrode and preparation method thereof

A composite metal, sandwich technology, applied in electrode manufacturing, structural parts, electrode rolling/calendering, etc., can solve the problem of difficult to achieve uniform mixing of metal lithium and composite, difficult to ensure batch reproducibility product consistency, difficult to achieve Large-scale production and other problems, to achieve the effect of improving lithium dendrite growth, reducing surface current density, and ensuring consistency

Active Publication Date: 2018-07-31
TSINGHUA UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Each of these methods has certain limitations. For example, the molten lithium filling method needs to melt metal lithium first, so there is a big safety hazard; the electrochemical pre-deposition lithium method involves the disassembly and reassembly of the battery, so the operation is complicated and difficult. Realize large-scale production; it is difficult to achieve uniform mixing between metal lithium and the compound in the repeated rolling method (patent application number 201710051717.2)
In addition, these methods are difficult to guarantee batch-to-batch reproducibility and product consistency

Method used

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  • Sandwiched-structure composite metal lithium negative electrode and preparation method thereof
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  • Sandwiched-structure composite metal lithium negative electrode and preparation method thereof

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preparation example Construction

[0025] A method for preparing a composite metal lithium negative electrode with a sandwich structure provided by the present invention is characterized in that the method comprises the following steps:

[0026] 1) Dispersing the interface layer material in water or an organic solvent to prepare a slurry, the solid content of the slurry is preferably 3-10%;

[0027] The prepared slurry is evenly coated on the metal foil or diaphragm by a coating machine, and dried for use; a certain amount of binder can also be added between the slurry, and the interface layer material and the binder The mass ratio is preferably 1:0.01~0.4; the binder is usually one or more of polyvinylidene fluoride, sodium carboxymethyl cellulose and styrene-butadiene rubber; the organic solvent can be ethanol, iso One or more mixtures of propanol and N-methylpyrrolidone.

[0028] 2) Stack the current collector, the lithium strip, and the metal foil or separator coated with the interface layer material obtai...

Embodiment 1

[0033] A copper mesh / lithium strip / graphene composite metal lithium negative electrode, the preparation process of which is as follows:

[0034] Mix graphene and polyvinylidene fluoride with a mass ratio of 1:0.4 evenly, then add N-methylpyrrolidone to prepare a slurry, the solid content of the slurry is 5%, and coat the slurry on the copper foil with a coating machine (referred to as carbon-coated copper foil), and placed in an oven at 90 degrees Celsius to dry for 2 hours for later use.

[0035] Copper mesh (400 mesh), lithium strip (50 μm), and carbon-coated copper foil are aligned and stacked (the carbon layer of the carbon-coated copper foil is placed toward the ultra-thin lithium strip), and rolled by a rolling mill.

[0036] After rolling, the copper foil on the upper layer of the sandwich structure is peeled off (the graphene layer sticks to the surface of the ultra-thin lithium strip after rolling), and finally a composite metal lithium negative electrode with a coppe...

Embodiment 2

[0039] A copper foil / lithium strip / reduced graphene oxide (rGO) composite lithium metal negative electrode, the preparation process of which is as follows:

[0040]The mixture of reduced graphene oxide, sodium carboxymethyl cellulose and styrene-butadiene rubber with a mass ratio of 1:0.1 (the mass ratio of sodium carboxymethyl cellulose and styrene-butadiene rubber in the mixture is 1:1) was mixed evenly, and then super Pure water is prepared into a slurry, the solid content of the slurry is 5%, the slurry is coated on the diaphragm (referred to as carbon-coated diaphragm) with a coating machine, and placed in a vacuum oven at 60 degrees Celsius to dry for 6 hours for later use.

[0041] Copper foil, lithium strip (30 μm), and carbon-coated separator are aligned and stacked (the carbon layer of the carbon-coated separator is placed toward the ultra-thin lithium strip), and rolled by a rolling mill.

[0042] After rolling, the separator on the upper layer of the sandwich struc...

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Abstract

A sandwiched-structure composite metal lithium negative electrode and a preparation method thereof belong to the technical field of a secondary battery. The sandwiched-structure composite negative electrode is formed by laminating a current collector, a lithium belt and an interface layer from bottom to top. The preparation method of the sandwiched-structure composite metal lithium negative electrode comprises the steps of firstly, preparing paste from an interface layer material, coating the paste on a metal foil or a separator, and drying for use; secondly, sequentially laminating the current collector, the lithium belt and the metal foil or the separator coated with the interface layer material, and rolling the three layers by a rolling machine; and finally, stripping the metal foil orthe separator of a sandwiched-structure surface layer obtained by pressing to further obtain the composite metal lithium negative electrode with the interface layer. The preparation method is convenient to operate and simple in process, automatic roll formation and continuous production can be achieved, and meanwhile, the product consistency and the reproducibility among batches can be ensured. With the sandwiched-structure composite metal lithium negative electrode obtained by the method, the lithium dendrites growth can be improved, and the cycle lifetime of the battery is prolonged.

Description

technical field [0001] The invention relates to a metal lithium negative electrode of a secondary battery and a preparation method thereof, in particular to a roll-to-roll continuous preparation of a composite metal lithium negative electrode with a sandwich structure and the preparation thereof, belonging to the technical field of secondary batteries. Background technique [0002] Metal-lithium batteries (such as lithium-sulfur batteries, lithium-air batteries) have become a research hotspot in the field of chemical power sources because of their higher theoretical energy density than existing commercial lithium-ion batteries. Metal lithium anode is a key component of metal lithium batteries, and its safe application has become a decisive factor for the next generation of high energy density metal lithium batteries. [0003] Metal lithium anode has a very high theoretical specific capacity (3860mAh g -1 ) and extremely low potential (-3.04 V, compared to standard hydrogen ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/134H01M4/1395H01M4/04H01M10/052
CPCH01M4/0435H01M4/134H01M4/1395H01M10/052Y02E60/10
Inventor 张强李滔程新兵石鹏
Owner TSINGHUA UNIV
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