EP-4738452-A1 - NEGATIVE ELECTRODE FOR RECHARGEABLE LITHIUM BATTERY AND RECHARGEABLE LITHIUM BATTERY INCLUDING THE SAME

Abstract

A negative electrode for a rechargeable lithium battery and a rechargeable lithium battery including the negative electrode are provided. The negative electrode includes: a negative electrode current collector including a carbon layer including a first porous substrate and a carbon-based material existing inside the first porous substrate and a silicon layer including a second porous substrate and a silicon-based negative electrode active material existing inside the second porous substrate; and a negative electrode active material layer arranged on a surface of the negative electrode current collector and including a negative electrode active material.

Inventors

• LEE, SEUNGJAE
• JUNG, MYUNG-SUNG
• BAE, Nanyoung
• SONG, YEJI
• LEE, SANGHEON

Assignees

• SAMSUNG SDI CO., LTD.

Dates

Publication Date

20260506

Application Date

20251021

Claims (15)

1. A negative electrode (20) for a rechargeable lithium battery (100), comprising: a negative electrode current collector (1) comprising a carbon layer comprising a first porous substrate and a carbon-based material inside the first porous substrate, and a silicon layer (3) comprising a second porous substrate and a silicon-based negative electrode active material inside the second porous substrate; and a negative electrode active material layer comprising a negative electrode active material and arranged on a surface of the negative electrode current collector (1).
2. The negative electrode (20) as claimed in claim 1, wherein the first porous substrate and the second porous substrate each independently comprise a metal, and the metal comprises copper, nickel, stainless, titanium, aluminum, or a combination thereof.
3. The negative electrode (20) as claimed in claim 1 or 2, wherein a thickness of the first porous substrate is about 5 µm to about 500 µm, and/or a thickness of the second porous substrate is about 5 µm to about 500 µm.
4. The negative electrode (20) of any one of the preceding claims, wherein a porosity of the first porous substrate is greater than or equal to about 50%, and/or a porosity of the second porous substrate is greater than or equal to about 50%.
5. The negative electrode (20) of any one of the preceding claims, wherein pores (5) inside the first porous substrate each have a size of about 300 µm to about 1,000 µm, and/or pores (5) inside the second porous substrate each have a size of about 300 µm to about 1,000 µm.
6. The negative electrode (20) of any one of the preceding claims, wherein the carbon-based material comprises amorphous carbon.
7. The negative electrode (20) of any one of the preceding claims, wherein the carbon layer further comprises a binder, an amount of the carbon-based material in the carbon layer is about 10 wt% to about 30 wt% based on a total weight of 100 wt% of the carbon layer excluding the first porous substrate, and an amount of the binder is about 70 wt% to about 90 wt% based on the total weight of 100 wt% of the carbon layer excluding the first porous substrate.
8. The negative electrode (20) of any one of the preceding claims, wherein the silicon-based negative electrode active material comprises a silicon-carbon composite.
9. The negative electrode (20) of any one of the preceding claims, wherein the silicon layer (3) further comprises a binder and a conductive material, an amount of the silicon-based negative electrode (20) active material is about 89 wt% to about 99.9 wt% based on a total weight of 100 wt% of the silicon layer (3) excluding the second porous substrate in the silicon layer (3), an amount of the binder is about 1 wt% to about 10 wt% based on the total weight of 100 wt% of the silicon layer (3) excluding the second porous substrate in the silicon layer (3), and an amount of the conductive material is about 0.1 wt% to about 1 wt% based on the total weight of 100 wt% of the silicon layer (3) excluding the second porous substrate in the silicon layer (3).
10. The negative electrode (20) of any one of the preceding claims, wherein: the carbon layer comprises a first carbon layer (1A) and a first carbon layer (1B); the first porous substrate comprises a first porous substrate (1A) and a first porous substrate (1B); and the carbon-based material comprises a first carbon-based material (1A) and a carbon-based material (1B), wherein the silicon layer (3) is on the first carbon layer (1A), and the first carbon layer (1B) is on the silicon layer (3), and wherein the first carbon layer (1A) comprises the first porous substrate (1A) and the first carbon-based material (1A) inside the first porous substrate (1A), and the first carbon layer (1B) comprises the first porous substrate (1B) and the first carbon-based material (1B) inside the first porous substrate (1B).
11. The negative electrode (20) as claimed in claim 10, wherein a thickness of the silicon layer (3) is about 50 thickness% to about 99 thickness% based on 100 thickness% of the negative electrode current collector (1), and a thickness sum of the first carbon layer (1A) and the first carbon layer (1B) is about 1 thickness% to about 50 thickness% based on 100 thickness% of the negative electrode current collector (1).
12. The negative electrode (20) as claimed in claim 10 or 11, wherein the first carbon layer (1A) and the first carbon layer (1B) have a thickness ratio of about 1:9 to about 9:1.
13. The negative electrode (20) of any one of the preceding claims, wherein the negative electrode active material comprises a carbon-based negative electrode active material, a silicon-based negative electrode active material, or a combination thereof.
14. The negative electrode (20) of any one of the preceding claims, wherein the negative electrode active material layer has a structure of one layer or two or more layers.
15. A rechargeable lithium battery (100), comprising a positive electrode (10), the negative electrode (20) according to any one of the preceding claims, and an electrolyte.

Description

BACKGROUND 1. Field One or more embodiments of the present disclosure relate to a negative electrode for a rechargeable lithium battery and a rechargeable lithium battery including the same. 2. Description of the Related Art Rechargeable lithium batteries, known for their portability and high energy density, are widely used as power sources in mobile information devices (terminals) such as smart phones, laptops, and/or the like. Recently, there has been active research into developing rechargeable lithium batteries with enhanced (high) safety and (high) capacity for applications as power sources for hybrid vehicles and/or electric vehicles or power storage apparatuses for storing electric power (e.g., power storage systems). To develop an electrode for rechargeable lithium batteries that deliver high capacity and energy density, it is desirable to use electrode plates with high density. However, as electrode plates become more densely packed, efforts have been made to reduce their internal resistance. Among various approaches, the use of a carbon layered foil (CLF) substrate has been considered for the negative electrode current collector. A CLF substrate is formed by coating a carbon layer onto a metal foil (e.g., copper foil), which is generally used as a negative electrode current collector, and has advantages such improved adhesion between the electrode plate and the substrate, and/or reduced interfacial resistance. However, the CLF substrate may adversely affect the energy density of the battery due to the thickness of the carbon coating. To mitigate this issue, increasing the density of the electrode plate has been proposed. Nevertheless, this may lead to increased resistance, which may negatively impact overall battery performance. SUMMARY In accordance with the present disclosure, a negative electrode as set forth in independent claim 1 and a rechargeable lithium battery as set forth in independent claim 15, are provided. Currently preferred embodiments are described in the dependent claims. One or more aspects of embodiments of the present disclosure are directed toward a negative electrode for a rechargeable lithium battery capable of improving adhesive strength and reducing interfacial resistance without affecting the energy density of the rechargeable lithium battery. One or more aspects of embodiments of the present disclosure are directed toward a rechargeable lithium battery having excellent or suitable battery performance by including the negative electrode. Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments. According to one or more embodiments of the present disclosure, a negative electrode for a rechargeable lithium battery includes: a negative electrode current collector including a carbon layer including a first porous substrate and a carbon-based material inside (e.g., in) the first porous substrate, and a silicon layer including a second porous substrate and a silicon-based negative electrode active material inside (e.g., in) the second porous substrate; and a negative electrode active material layer including a negative electrode active material and on (e.g., arranged on or disposed on) a (e.g., at least one) surface of the negative electrode current collector. According to one or more embodiments of the present disclosure, a rechargeable lithium battery includes a positive electrode, the negative electrode, and an electrolyte. The negative electrode for a rechargeable lithium battery according to one or more embodiments may improve adhesive strength and interfacial resistance without affecting the energy density of the rechargeable lithium battery. The rechargeable lithium battery according to one or more embodiments may have excellent or suitable battery performance by including the aforementioned negative electrode and the positive electrode. For example, the integration of the negative electrode structure-featuring a carbon-based material and a silicon-based negative electrode active material within porous substrates-should significantly enhance the overall electrochemical stability and efficiency of the battery system. This configuration not only improves the mechanical integrity and adhesion between electrode layers but also facilitates efficient lithium-ion transport and charge transfer during cycling. As a result, the battery may achieve higher capacity retention, reduced internal resistance, and/or improved rate capability, all of which contribute to enhanced performance in both high-power and long-duration applications. Furthermore, the enhanced electrode design may support the development of compact and lightweight battery cells, making them advantageous for use in electric vehicles, portable electronics, and/or energy storage systems. BRIEF DESCRIPTION OF DRAWINGS The accompanying drawings are included to provide a further understandin