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KR-20260066959-A - CURRENT COLLECTOR FOR DRY ELECTRODE, DRY ELECTRODE AND LITHIUM SECONDARY BATTERY COMPRISING THE SAME

KR20260066959AKR 20260066959 AKR20260066959 AKR 20260066959AKR-20260066959-A

Abstract

The present invention relates to a current collector for a dry electrode comprising: a current collector; and a buffer layer positioned on the current collector and containing a carbon-based conductive material and a cellulose-based binder, wherein the carbon-based conductive material is a carbon nanotube or graphene oxide, and the thickness ratio of the buffer layer to the current collector (buffer layer thickness/current collector thickness) is 0.05 to 0.4.

Inventors

  • 정용조
  • 홍기주
  • 배창근
  • 이재은

Assignees

  • 포스코홀딩스 주식회사

Dates

Publication Date
20260512
Application Date
20241105

Claims (10)

  1. The whole house; and It comprises a buffer layer located on the above current collector and containing a carbon-based conductive material and a cellulose-based binder, The above carbon-based conductive material is carbon nanotubes or graphene oxide, and A current collector for a dry electrode, wherein the thickness ratio of the buffer layer to the current collector (buffer layer thickness / current collector thickness) is 0.05 to 0.4.
  2. In paragraph 1, The above carbon-based conductive material is a current collector for dry electrodes, which is a carbon nanotube.
  3. In paragraph 1, A current collector for a dry electrode, wherein the content of the carbon-based conductive material is 68 to 87 weight percent based on the total weight of the carbon-based conductive material and the cellulose-based binder.
  4. In paragraph 2, The above carbon nanotube is a current collector for dry electrodes having an aspect ratio of 20 to 50.
  5. In paragraph 2, The above carbon nanotube is a current collector for dry electrodes having an average length of 500 nm to 1.5 μm.
  6. In paragraph 2, The above carbon nanotube is a current collector for dry electrodes having an average diameter of 5 to 25 nm.
  7. In paragraph 2, The above carbon nanotube is a current collector for dry electrodes having an average aspect ratio of 20 to 200.
  8. The whole house; A buffer layer located on the above current collector and containing a carbon-based conductive material and a cellulose-based binder; and It includes an electrode active material layer located on the above buffer layer and containing an electrode active material, The above carbon-based conductive material is carbon nanotubes or graphene oxide, and A dry electrode in which the thickness ratio of the buffer layer to the current collector (buffer layer thickness / current collector thickness) is 0.05 to 0.4.
  9. In paragraph 8, The above electrode active material is a dry electrode that is a positive electrode active material or a negative electrode active material.
  10. A lithium secondary battery comprising the dry electrode of claim 8.

Description

Current collector for dry electrode, dry electrode and lithium secondary battery comprising the same The present invention relates to a current collector for a dry electrode, a dry electrode, and a lithium secondary battery including the same. Recently, as the demand for portable electronic products such as laptops, video cameras, and mobile phones has increased rapidly, and the development of electric vehicles, energy storage batteries, robots, and satellites has accelerated, research on high-performance secondary batteries capable of repeated charging and discharging is actively underway. Currently commercialized secondary batteries include nickel-cadmium, nickel-hydrogen, nickel-zinc, and lithium secondary batteries. Among these, lithium secondary batteries are gaining attention for their advantages, such as the ability to freely charge and discharge with almost no memory effect compared to nickel-based secondary batteries, a very low self-discharge rate, and high energy density. Generally, a lithium secondary battery is structured such that a lithium electrolyte is impregnated into an electrode assembly comprising a positive electrode containing a lithium transition metal oxide as an electrode active material, a negative electrode containing a carbon-based active material, and a separator. A conventional method for manufacturing electrodes involves preparing an electrode composite by dispersing an electrode active material, a conductive material, a binder, etc., in a dispersion medium (solvent), and then coating and drying it on a current collector. However, when drying the electrode composite coated on the current collector, a migration phenomenon occurs in which the binder and the dispersion medium move together to the surface as the dispersion medium within the electrode composite evaporates. Consequently, the distribution of the binder within the electrode composite layer, particularly in the direction of the layer thickness, becomes uneven, leading to a deterioration in the adhesion of the electrode composite layer and a deterioration in the input/output characteristics of the battery. To solve these problems, a dry electrode technology has recently been proposed that manufactures electrodes through powder mixing without a dispersion medium as an electrode composite. A dry electrode is an electrode manufactured by drying an electrode slurry containing an electrode active material and then coating the resulting powdered electrode material onto a current collector. Since this dry electrode does not contain a dispersion medium (solvent) in the coating slurry, it alleviates the non-uniform distribution of the binder and increases binder uniformity, which has the advantage of being favorable for output and rapid charging. FIG. 1 is a conceptual diagram of a current collector for a dry electrode according to one embodiment of the present invention. FIG. 2 is a conceptual diagram of a dry electrode according to another embodiment of the present invention. Terms such as first, second, and third are used to describe various parts, components, regions, layers, and/or sections, but are not limited thereto. These terms are used solely to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, the first part, component, region, layer, or section described below may be referred to as the second part, component, region, layer, or section without departing from the scope of the present invention. The technical terms used herein are for the reference of specific embodiments only and are not intended to limit the invention. The singular forms used herein include plural forms unless phrases clearly indicate otherwise. As used in the specification, the meaning of "comprising" specifies certain characteristics, areas, integers, steps, actions, elements, and/or components, and does not exclude the presence or addition of other characteristics, areas, integers, steps, actions, elements, and/or components. When it is stated that one part is "above" or "on" another part, it may be directly above or on the other part, or other parts may be involved in between. In contrast, when it is stated that one part is "directly above" another part, no other parts are interposed in between. Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined. Also, unless otherwise specified, % means weight %, and 1 ppm is 0.0001 weight %. In this specification, the term “combination(s) of these” described in the Markush-type expression means one or more mixtures or combinations selected from the g