Metal lithium composite cathode as well as preparation method and application thereof

A metal lithium and metal lithium layer technology, which is applied in electrode manufacturing, electrode rolling/calendering, battery electrodes, etc., can solve the problems of easy flying of lithium powder, powder failure of negative electrode sheets, uneven thickness, etc., to improve charging and discharging. Efficiency, improving the density of the negative electrode, and the effect of uniform and flat lithium layer

Inactive Publication Date: 2019-03-01
天齐锂业(江苏)有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Lithium sources for negative electrode pre-lithiation include: lithium powder, lithium strip, etc. Among them, passivated lithium powder is mostly used as lithium source in traditional metal lithium composite negative electrodes, which is coated on the surface of the negative electrode sheet or mixed into the battery slurry. It is easy to implement, but its disadvantage is that lithium powder is easy to fly during use, causing great environmental pollution, low safety performance, and high cost of lithium powder
However, using ultra-thin lithium strips as a lithium sourc

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  • Metal lithium composite cathode as well as preparation method and application thereof
  • Metal lithium composite cathode as well as preparation method and application thereof
  • Metal lithium composite cathode as well as preparation method and application thereof

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[0022] As an aspect of the technical solution of the present invention, it relates to a method for preparing a metal lithium composite negative electrode, which includes:

[0023] At least using a vacuum physical deposition method to deposit a metal lithium layer on the surface of the polymer film to obtain a composite belt;

[0024] A composite tape is set on both sides of a negative electrode sheet, and the metallic lithium layer in each composite tape is in contact with the negative electrode sheet, and then pressure is applied to the composite structure composed of the negative electrode sheet and the composite tape to obtain both sides A negative electrode sheet combined with a lithium metal layer is the metal lithium composite negative electrode.

[0025] In some embodiments, the preparation method includes: at least using a magnetron sputtering method or an evaporation method to deposit a lithium metal layer on the surface of the polymer film.

[0026] Further, the material of ...

Embodiment 1

[0050] Apply white oil evenly on the PI (polyimide) film as a base material for vacuum evaporation of lithium. A vacuum evaporation equipment is used to deposit a 1 μm lithium metal layer on the PI film to obtain a lithium metal / PI film. Then like figure 1 As shown, the upper and lower two bands of metal lithium / PI film are rolled together with the graphite negative electrode, the rolling pressure is 0.1 MPa, and the rolling speed is 0.1 m / min. Lithium metal adheres to the negative electrode. Finally, the PI film was peeled off to obtain a graphite negative electrode coated with 1μm lithium metal on both sides. The compact density of the graphite negative electrode reached 1.4g / cm. -3 . The graphite metal lithium composite negative electrode and the lithium iron phosphate positive electrode form a single cell with an energy density of 130wh / kg. The first charge and discharge efficiency of the negative electrode is increased to 99.9%, such as figure 2 Shown.

Embodiment 2

[0052] A small amount of lithium fluoride powder is sprayed on the PET (polyethylene terephthalate) film as a substrate for vacuum evaporation of lithium. A vacuum evaporation equipment was used to deposit a 45 μm lithium metal layer on the PET film to obtain a lithium metal / PET film. Then like figure 1 As shown, the upper and lower two belts of metal lithium / PET film and the hard carbon negative electrode are rolled together, the rolling pressure is 400 MPa, and the rolling speed is 60 m / min. Lithium metal adheres to the negative electrode, and finally the PET film is peeled off to obtain a hard carbon negative electrode coated with lithium metal of 45 μm on both sides. The hard carbon metal lithium composite negative electrode and the sulfur positive electrode are assembled into a single battery, which can work normally with an initial energy density of 500wh / kg.

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Abstract

The invention discloses a metal lithium composite cathode as well as a preparation method and application thereof. The preparation method comprises the following steps: forming a metal lithium layer on the surface of a polymer film in a depositing manner at least by adopting a vacuum physical deposition method, and obtaining a composite band; respectively arranging one composite band at two sidesof a cathode piece, enabling the metal lithium layer in each composite band to contact the cathode piece, applying pressure to a composite structure consisting of the cathode piece and the composite band, obtaining the cathode piece with two side surfaces being respectively combined with the metal lithium layer, thus obtaining the metal lithium composite cathode. The lithium band is prepared through the vacuum physical deposition method, and a pressure-rolling process is combined, so that the metal lithium layer can be uniformly, continuously and thinly covered on the cathode, thereby obtaining a pre-lithiated cathode. The defect that the lithium band is easily broken is avoided, and at the same time the cathode is compacted, and the density of the cathode is increased. The metal lithium composite cathode is utilized to improve the first-time charge/discharge efficiency of a cathode material, can serve as a lithium-containing cathode and be matched with a lithium-free anode, and has abroad application prospect.

Description

Technical field [0001] The invention relates to a method for preparing a lithium-containing negative electrode, in particular to a metal lithium composite negative electrode and a preparation method thereof, and its application in a lithium battery, belonging to the technical field of lithium ion batteries. Background technique [0002] Currently marketed lithium secondary batteries widely use carbon materials such as graphite as a negative electrode. Although graphite has higher safety than metal lithium, its theoretical specific capacity is lower, only 372mAh / g. Therefore, the development of high-capacity anode materials has attracted attention. For example, the theoretical specific capacity of silicon is as high as 4200mAh / g, and metal lithium deposition is not easy to occur during the charging and discharging process, and its capacity and safety are higher than graphite. The theoretical specific capacity of hard carbon is 500-700mAh / g. The common problem with these materia...

Claims

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Application Information

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IPC IPC(8): H01M4/04H01M4/139H01M10/052
CPCH01M4/0423H01M4/0435H01M4/139H01M10/052Y02E60/10
Inventor 聂阳邹崴詹彬鑫曹乃珍
Owner 天齐锂业(江苏)有限公司
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