Search

KR-20260067435-A - A NEGATIVE ELECTRODE AND A PREPARATION METHOD THEREOF

KR20260067435AKR 20260067435 AKR20260067435 AKR 20260067435AKR-20260067435-A

Abstract

The present invention relates to a cathode and a method for manufacturing the same. The cathode comprises a coating layer containing a ferromagnetic material on the surface of the cathode active layer, thereby enabling electrostatic repulsion against oxygen ions during the charging and discharging of a secondary battery. Accordingly, the cathode can improve the movement of lithium ions caused by oxygen ions, thus having the advantage of exhibiting excellent cycle characteristics.

Inventors

  • 김성현
  • 김형권

Assignees

  • 주식회사 엘지에너지솔루션

Dates

Publication Date
20260513
Application Date
20241104

Claims (15)

  1. cathode current collector, A cathode active layer located on at least one surface of the above-mentioned cathode current collector and comprising a cathode active material, and It includes a coating layer located on the above-mentioned cathode active layer and comprising a paramagnetic material; The above coating layer is a negative electrode having an electrostatic repulsion against oxygen ions during charging and discharging of a secondary battery.
  2. In paragraph 1, The above paramagnetic material is a cathode comprising one or more of Fe₃O₄ , Pt-Ni alloy, Fe-based alloy, Tb-based alloy, Nd-based alloy , and Sm-based alloy.
  3. In paragraph 1, The above paramagnetic body is a cathode having a secondary particle form in which paramagnetic primary particles aggregate to form a hollow structure.
  4. In paragraph 1, A cathode having an average particle size (D 50 ) of the paramagnetic material in the range of 0.5 μm to 50 μm.
  5. In paragraph 1, A cathode having an average thickness of the coating layer in the range of 10 μm to 500 μm.
  6. In paragraph 1, The above coating layer is a cathode having a thickness ratio of 5% to 30% based on the average thickness of the cathode active layer.
  7. In paragraph 1, The above-mentioned cathode active material comprises one or more carbon-based cathode active materials selected from natural graphite, artificial graphite, Kish graphite, pyrolytic carbon, carbon microbeads, mesophase calcined carbon made from tar and pitch, and graphitized coke.
  8. In paragraph 1, The above-mentioned cathode active material further comprises one or more silicon-based cathode active materials selected from Si, SiC and SiO q (wherein 0.5≤q≤2.5).
  9. Step (S1) of applying a cathode slurry containing a cathode active material to at least one surface of a cathode current collector, A step (S2) of coating a coating solution containing a paramagnetic material onto an applied cathode slurry, and The method includes a step (S3) of drying the above cathode slurry and coating solution, and The above coating is a method for manufacturing a cathode performed by spray drying.
  10. In Paragraph 9, A method for manufacturing a cathode in which the above spray drying is performed at a temperature in the range of 150℃ to 300℃.
  11. In Paragraph 9, A method for manufacturing a cathode in which the above coating solution is sprayed at a flow rate in the range of 100 to 300 m/min.
  12. In Paragraph 9, A method for manufacturing a cathode comprising one or more of the paramagnetic materials selected from Fe₃O₄ , Pt-Ni alloy, Fe-based alloy, Tb-based alloy, Nd-based alloy , and Sm-based alloy.
  13. In Paragraph 9, A method for manufacturing a cathode comprising 60 to 99 parts by weight of paramagnetic primary particles and 1 to 40 parts by weight of a binder, wherein the above coating solution comprises 60 to 99 parts by weight of paramagnetic primary particles.
  14. In Paragraph 13, A method for manufacturing a cathode in which the above paramagnetic primary particles have an average particle size (D 50 ) in the range of 50 nm to 10 μm.
  15. In Paragraph 9, The above coating solution is a method for manufacturing a cathode having a solid content in the range of 5% or more and less than 50%.

Description

A negative electrode and a preparation method thereof The present invention relates to a cathode and a method for manufacturing the same. Recently, lithium-ion batteries are being widely applied not only to small devices such as portable electronic devices but also to medium-to-large devices such as battery packs or power storage systems for hybrid and electric vehicles. In particular, with the recent increase in concern for environmental issues, the demand base for high-capacity batteries is expanding due to the growth of the market for devices employing high-capacity batteries, such as electric vehicles and hybrid electric vehicles, which can replace fossil fuel-using vehicles like gasoline and diesel cars—a major cause of air pollution. To manufacture lithium-ion batteries that serve as the power source for these devices, there is a demand for high-capacity electrode designs that possess high energy density, high output, and high discharge voltage. Generally, a lithium secondary battery has a structure in which an electrode assembly consisting of a positive electrode, a negative electrode, and a separator is impregnated in a lithium electrolyte. At this time, each electrode is manufactured by coating an electrode slurry onto a current collector. The electrode slurry is prepared by mixing an electrode active material for storing energy, a conductive material for providing electrical conductivity, and a binder for adhering to the current collector and providing mutual bonding force in a solvent such as NMP (N-methyl pyrrolidone). During charging, a lithium desorption reaction is induced in the positive electrode, where lithium contained in the positive electrode active material is oxidized and released, while a lithium insertion reaction occurs in the negative electrode, where lithium is reduced and enters the negative electrode active material. Generally, since the desorption reaction in the positive electrode active material is faster than the insertion reaction in the negative electrode active material, the charge/discharge performance of the lithium secondary battery is primarily determined by the negative electrode. Meanwhile, high-Ni cathode active materials are frequently applied to achieve high capacity and high energy density in conventional lithium secondary batteries. However, due to structural instability, high-Ni cathode active materials tend to release oxygen ions as charge-discharge cycles progress. Before forming oxygen gas, these released oxygen ions damage the surface of the active layer containing the cathode active material and decompose the electrolyte during charging and discharging. Furthermore, these oxygen ions act as a factor hindering the movement of lithium ions on the anode surface, increasing resistance at the anode surface and thereby lowering the cycle characteristics of the anode. The present invention is capable of various modifications and may have various embodiments, and specific embodiments are to be described in detail in the detailed description. In the present invention, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not excluding in advance the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof. In this specification, "include as a main component" may mean including a defined component in an amount of 50 wt% or more (or 50 volume% or more), 60 wt% or more (or 60 volume% or more), 70 wt% or more (or 70 volume% or more), 80 wt% or more (or 80 volume% or more), 90 wt% or more (or 90 volume% or more), or 95 wt% or more (or 95 volume% or more) with respect to the total weight (or total volume). For example, "include carbon atoms as a main component" may mean including 50 wt% or more, 60 wt% or more, 70 wt% or more, 80 wt% or more, 90 wt% or more, or 95 wt% or more based on the total weight of the carbon-based compound. In some cases, it may mean that the entire carbon-based compound consists of carbon atoms and is included in an amount of 100 wt%. In addition, in this specification, "average particle size (D 50 )" refers to the particle size at which the cumulative value of the particle size distribution is 50%, and this is also referred to as the median diameter. The average particle size may be measured in a manner commonly applied in the art. For example, the average particle size may be measured using a particle size analyzer or an analytical instrument utilizing the laser diffraction scattering particle size distribution method. In the present invention, it may be a value measured by an analytical instrument utilizing the laser diffraction scattering particle size distribution method. In this specification, "primary particle" may refer to an ultimate particle, meaning an aggregate of crystal particles having a crystal struct