KR-20260062842-A - NEGATIVE ELECTRODE FOR RECHARGEABLE LITHIUM BATTERY AND RECHARGEABLE LITHIUM BATTERY INCLUDING THE SAME

KR20260062842AKR 20260062842 AKR20260062842 AKR 20260062842AKR-20260062842-A

Abstract

The present invention relates to a negative electrode for a lithium secondary battery and a lithium secondary battery, wherein the negative electrode for the lithium secondary battery comprises: a negative electrode current collector comprising a first porous substrate and a carbon layer comprising a carbon-based material present within the first porous substrate, and a silicon layer comprising a silicon-based negative electrode active material present within the second porous substrate; and a negative electrode active material layer located on at least one surface of the negative electrode current collector and comprising a negative electrode active material.

Inventors

이승재
정명성
배난영
송예지
이상헌

Assignees

삼성에스디아이 주식회사

Dates

Publication Date: 20260507
Application Date: 20251017
Priority Date: 20241029

Claims (15)

A carbon layer comprising a first porous substrate and a carbon-based material present inside the first porous substrate, and A negative current collector comprising a second porous substrate and a silicon layer comprising a silicon-based negative active material present inside the second porous substrate; and A negative active material layer comprising a negative active material located on at least one surface of the above negative current collector, the negative active material layer comprising a negative active material; Negative electrode for lithium secondary batteries.
In paragraph 1, The first porous substrate and the second porous substrate each independently comprise a metal, and The above metal includes copper, nickel, stainless steel, titanium, aluminum, or a combination thereof. Negative electrode for lithium secondary batteries.
In Paragraph 1, The thickness of the first porous substrate and the second porous substrate is independently 5 μm to 500 μm, Negative electrode for lithium secondary batteries.
In paragraph 1, The porosity of the first porous substrate and the second porous substrate is independently 50% or more, Negative electrode for lithium secondary batteries.
In paragraph 1, The pore sizes within the first porous substrate and the second porous substrate are each independently 300 μm to 1,000 μm, Negative electrode for lithium secondary batteries.
In paragraph 1, The above carbon-based material includes amorphous carbon, Negative electrode for lithium secondary batteries.
In paragraph 1, The carbon layer further comprises a binder together with the carbon-based material, and The content of the carbon-based material in the carbon layer is 10% to 30% by weight with respect to 100% by weight of the carbon layer excluding the first porous substrate, and The content of the above binder is 70% to 90% by weight with respect to 100% by weight of the carbon layer excluding the first porous substrate, Negative electrode for lithium secondary batteries.
In paragraph 1, The above silicon-based negative electrode active material comprises a silicon-carbon composite, Negative electrode for lithium secondary batteries.
In paragraph 1, The silicon layer further comprises a binder and a conductive material together with the silicon-based negative electrode active material, and The content of the silicon-based negative electrode active material in the silicon layer is 89% to 99.9% by weight with respect to 100% by weight of the silicon layer excluding the first porous substrate, and The content of the above binder is 1% to 10% by weight with respect to 100% by weight of the silicon layer excluding the first porous substrate, and The content of the conductive material is 0.1% to 1% by weight relative to 100% by weight of the silicon layer excluding the first porous substrate. Negative electrode for lithium secondary batteries.
In Paragraph 1, The above-mentioned cathode current collector comprises a first' carbon layer, a silicon layer located on the first' carbon layer, and a first'' carbon layer located on the silicon layer. The above-mentioned first' carbon layer comprises a first' porous substrate and a first' carbon-based material existing inside the first' porous substrate, and The first carbon layer comprises a first porous substrate and a first carbon-based material present inside the first porous substrate. Negative electrode for lithium secondary batteries.
In Paragraph 10, The thickness of the silicon layer is 50% to 99% with respect to 100% thickness of the negative current collector, and The sum of the thicknesses of the first ' carbon layer and the first '' carbon layer is 1% to 50% with respect to 100% thickness of the cathode current collector, Negative electrode for lithium secondary batteries.
In Paragraph 10, The thickness ratio of the first' carbon layer and the first'' carbon layer is 1:9 to 9:1, Negative electrode for lithium secondary batteries.
In paragraph 1, The above negative electrode active material comprises a carbon-based negative electrode active material, a silicon-based negative electrode active material, or a combination thereof. Negative electrode for lithium secondary batteries.
In paragraph 1, The above-mentioned negative electrode active material layer has a structure of one layer or two or more layers, Negative electrode for lithium secondary batteries.
A positive electrode, a negative electrode according to any one of claims 1 to 14, and an electrolyte comprising, Lithium secondary battery.

Description

Negative electrode for rechargeable lithium battery and rechargeable lithium battery including the same The invention relates to a negative electrode for a lithium secondary battery and a lithium secondary battery including the same. Lithium-ion batteries are widely used as power sources for mobile information terminals such as smartphones and laptops because they offer high energy density and portability. Recently, active research is being conducted on lithium-ion batteries with high safety and high capacity for use as power sources for hybrid or electric vehicles, or for power storage. To develop electrodes for lithium secondary batteries that achieve high capacity and high energy density, it is necessary to increase the density of the electrode plates, and research is being conducted to lower the resistance of the electrode plates as the plates become more densified. Among these, a Carbon Layered Foil (CLF) substrate is being considered as a cathode current collector. The above Carbon Layered Foil (CLF) substrate is formed by coating a carbon layer onto a metal foil (e.g., copper foil) conventionally used as a cathode current collector, and has the advantage of improving adhesion between the electrode plate and the substrate and reducing interfacial resistance. However, when using CLF substrates as electrode current collectors, the thickness of the carbon layer coated on the metal foil acts as a negative factor in realizing the energy density of the battery; furthermore, if the density of the electrode plates is increased to mitigate this, the resistance of the plates increases, which consequently has an adverse effect on battery performance. FIG. 1 is a top view of a porous substrate according to one embodiment. FIG. 2 is a cross-sectional view schematically illustrating a cathode current collector according to one embodiment. FIGS. 3 to 6 are schematic drawings illustrating a lithium secondary battery according to one embodiment. Specific embodiments are described below in detail so that those skilled in the art can easily implement them. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. The terms used herein are for describing exemplary embodiments only and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. Here, "combinations of these" refers to mixtures of components, laminates, composites, copolymers, alloys, blends, reaction products, etc. The terms "include," "equip," or "have" used herein are intended to specify the existence of the implemented features, numbers, steps, components, or combinations thereof, and should be understood as not excluding in advance the existence or addition of one or more other features, numbers, steps, components, or combinations thereof. In the drawings, thicknesses have been enlarged to clearly represent various layers and regions, and the same reference numerals have been used for similar parts throughout the specification. When a part such as a layer, film, region, or plate is described as being "on" or "on" another part, this includes not only cases where it is "immediately on" another part, but also cases where there is another part in between. Conversely, when a part is described as being "immediately on" another part, it means that there is no other part in between. In addition, the term “layer” here includes not only the shape formed on the entire surface when viewed in a plan view, but also the shape formed on some surfaces. The average particle size can be measured by methods widely known to those skilled in the art, for example, by measuring with a particle size analyzer, or by using transmission electron microscope images or scanning electron microscope images. Alternatively, the average particle size value can be obtained by measuring using dynamic light scattering and performing data analysis to count the number of particles for each particle size range, and then calculating from this. Unless otherwise defined, the average particle size may refer to the diameter (D 50 ) of a particle whose cumulative volume is 50% of the particle size distribution. Additionally, unless otherwise defined, the average particle size may be obtained by randomly measuring the size (diameter or length of the major axis) of about 20 particles from a scanning electron microscope image to obtain a particle size distribution, and taking the diameter (D 50 ) of the particle whose cumulative volume is 50% of the particle size distribution as the average particle size. Here, “or” is not interpreted in an exclusive sense; for example, “A or B” is interpreted to include A, B, A+B, etc. The term “metal” is interpreted as a concept that includes common metals, transition metals, and metalloids (semimetals). cathode One embodiment provides a cathode comprising: a first porous substrate and a carbon layer comprising a carb