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CN-121992360-A - Alkali metal vapor deposition device, pre-lithiation method, and pre-lithiated anode

CN121992360ACN 121992360 ACN121992360 ACN 121992360ACN-121992360-A

Abstract

The invention provides an alkali metal vapor deposition device, comprising an unwinding mechanism, a winding chamber for accommodating the winding mechanism, and a vapor deposition chamber for accommodating the alkali metal vapor deposition mechanism between the unwinding mechanism and the winding chamber, wherein an atmosphere separation mechanism is arranged between the winding chamber and the vapor deposition chamber, and the winding chamber is provided with a decompression mechanism capable of moving the winding chamber under the condition of maintaining the internal decompression state. The present invention also provides a pre-lithiation method using an alkali metal vapor deposition apparatus, a pre-lithiated negative electrode obtained by the pre-lithiation method, and a lithium ion secondary battery including the pre-lithiated negative electrode.

Inventors

  • Haruki Akiyoshi
  • Jin Sichen
  • WU CHEN
  • LI HAIMING
  • QIU XINPING

Assignees

  • 株式会社爱发科

Dates

Publication Date
20260508
Application Date
20241108

Claims (11)

  1. 1. An alkali metal vapor deposition apparatus comprising an unwinding mechanism, a winding chamber accommodating the winding mechanism, and a vapor deposition chamber accommodating the alkali metal vapor deposition mechanism between the unwinding mechanism and the winding chamber, An atmosphere separation mechanism is provided between the winding chamber and the vapor deposition chamber, and the winding chamber is provided with a decompression mechanism capable of moving the winding chamber while maintaining an internal decompression state or a mechanism capable of moving the winding chamber while maintaining an internal inert atmosphere.
  2. 2. The alkali metal vapor deposition device according to claim 1, wherein, The internal pressure-reduced state of the winding chamber means that the total pressure is in the range of 1.0E-5Pa to 10Pa, the oxygen partial pressure is in the range of 1.0E-7Pa to 1.0E-3Pa, and the water partial pressure is in the range of 1.0E-7Pa to 1.3E-3 Pa.
  3. 3. The alkali metal vapor deposition device according to claim 1 or 2, wherein, The pressure reducing mechanism is a cooling trap or an exhaust pump.
  4. 4. The alkali metal vapor deposition device according to claim 3, wherein, The cooling liquid in the cooling trap is a cooling liquid capable of achieving a temperature of-40 ℃ or lower.
  5. 5. The alkali metal vapor deposition device according to claim 3, wherein, The exhaust pump is a turbo molecular pump, a dry vacuum pump or a low-temperature pump.
  6. 6. The alkali metal vapor deposition device according to any one of claims 1 to 5, The alkali metal vapor deposition apparatus is further provided with a mechanism for unwinding and winding the mask to pattern the alkali metal film formed by vapor deposition.
  7. 7. The alkali metal vapor deposition device according to any one of claims 1 to 6, The alkali metal is sodium or lithium.
  8. 8. The alkali metal vapor deposition device according to any one of claims 1 to 7, The inert atmosphere includes a rare gas atmosphere or a nitrogen atmosphere.
  9. 9. A method of pre-lithiation by depositing lithium on a negative electrode substrate using the alkali metal deposition apparatus according to any one of claims 1 to 8.
  10. 10. The method of prelithiation as set forth in claim 9, wherein, The negative electrode is a graphite negative electrode or a silicon-based negative electrode.
  11. 11. A prelithiated anode made by using the prelithiation method of claim 9 or 10.

Description

Alkali metal vapor deposition device, pre-lithiation method, and pre-lithiated anode Technical Field The present invention relates to an apparatus for vapor deposition of an alkali metal on a flexible substrate (typically, a mesh substrate) and a vapor deposition method thereof. A typical example of the vapor deposition apparatus is an apparatus that performs vapor deposition in a roll-to-roll manner. The evaporation device can be used for example in thin film solar cell production, thin film cell production and flexible display production. Background In recent years, secondary batteries using energy storage technology of alkali metals such as lithium have been attracting attention. Among them, lithium ion batteries have a high energy density, and thus are applied to electronic devices, electric vehicles, and the like. Graphite is mainly used in the negative electrode material of the lithium ion battery, however, the theoretical capacity of graphite is only 372mAh/g. In order to meet the demand for increasing the energy density of lithium ion batteries in recent years, a negative electrode material having a higher capacity is desired. Therefore, in recent years, silicon-based negative electrodes have received attention. The theoretical capacity of pure silicon is 3579mAh/g (Li 15Si4), and that of silicon monoxide (SiO) is 2680mAh/g, which have a higher theoretical capacity than graphite. However, in the practical use of a silicon-based negative electrode, silicon is generally used as a silicon-based negative electrode in which silicon is used as an active material particle and the volume of the active material particle is greatly expanded and contracted during charge and discharge, and there are problems to be overcome such as breakage of the particle during charge and discharge, breakage of an interface coating film, and separation from a current collector. Further, there is a problem in handling the silicon-based anode in that the initial irreversible capacity of the silicon-based anode is larger than that of the graphite anode. This is because lithium ions react with an electrolyte or SiO material during initial charge to form a Solid Electrolyte Interface (SEI) layer mainly comprising lithium silicate (Li 4SiO4) and lithium oxide (Li 2 O). The initial coulombic efficiency (ICE: the ratio of initial discharge capacity to initial charge capacity upon initial charge-discharge, wherein the larger the irreversible capacity, the smaller the initial coulombic efficiency) of the graphite anode is 90 to 95%, and the ICE of the silicon-based anode is 70 to 90%, lower than that of graphite. In order to solve this problem, a technique called prelithiation (Pre-lithiation) has been proposed in the process of manufacturing a lithium ion battery (refer to patent document 1). The prelithiation technique refers to a process of adding lithium of irreversible capacity to the negative electrode before the battery is manufactured. The pre-lithiation technology can improve the energy density of the lithium ion battery and prolong the cycle life of the lithium ion battery. The irreversible capacity refers to lithium capacity consumed by a solid-electrolyte interlayer (SEI) formed on a negative electrode, which is mainly caused by decomposition of an electrolyte at the time of initial charge, and formation of the SEI is generally unavoidable in a secondary lithium battery. For example, several prelithiation methods have been reported as follows. (1) A prelithiation technique in which a metallic lithium foil is stuck or transferred to the surface of a negative electrode (refer to patent document 2 and patent document 3). (2) A technique of pre-lithiating a negative electrode by an electrochemical reaction with a counter electrode lithium metal by placing the negative electrode in an electrolyte tank (refer to patent document 4). (3) A technique of pre-lithiating a negative electrode by a direct oxidation-reduction reaction by immersing the negative electrode in a strongly reducing lithium-containing solution (see patent document 5). (4) A technique of applying a printable lithium composition containing a surface-Stabilized Lithium Metal Powder (SLMP) to the surface of a negative electrode to thereby obtain prelithiation (see patent documents 6 and 7). (5) A technique of pre-lithiating a negative electrode material by reacting the negative electrode material with a lithium metal source in a negative electrode powder material forming step or a negative electrode mixture forming step (refer to patent documents 8, 9 and 10). Here, the Physical Vapor Deposition (PVD) technique used is a production method advantageous in the thin film field, capable of filling the amount of lithium required for prelithiation with high accuracy, and highly active lithium metal is not easily affected by atmospheric gases due to the treatment under vacuum, and therefore is promising as a method for improving the energy density of a lithium ion battery.