JP-2026514532-A - Negative electrode for lithium-free secondary batteries and lithium-free secondary batteries containing the same

Abstract

The present invention relates to a negative electrode for a lithium-free secondary battery, a method for manufacturing the same, and a lithium-free secondary battery, which can improve the electrochemical properties and life characteristics of the lithium-free secondary battery. The negative electrode may include a conductive metal layer and a lithium electrodeposition induction layer formed on the conductive metal layer and containing an intermetallic compound to which copper and zinc are bonded.

Inventors

• サンハ・キム
• ドンヨン・ウォン
• インヨン・ヤン

Assignees

• エルジー エナジー ソリューション リミテッド
• 韓国科学技術院

Dates

Publication Date

20260511

Application Date

20240508

Priority Date

20230509

Claims (11)

1. A negative electrode for a lithium-free secondary battery, comprising a conductive metal layer; and a lithium electrodeposition induction layer formed on the conductive metal layer and containing an intermetallic compound to which copper and zinc are bonded.
2. The conductive metal layer comprises copper, as described in claim 1, for a lithium-free secondary battery negative electrode.
3. The lithium electrodeposition induction layer comprises an intermetallic compound in which copper and zinc are bonded in a weight ratio of 2:8 to 9.5:0.5, as described in claim 1, for a lithium-free secondary battery negative electrode.
4. The lithium electrodeposition induction layer is bonded with copper and zinc in a weight ratio of 3:7 to 9:1, and contains 0.01 to 5% by weight of an oxygen-containing intermetallic compound based on the total weight of the intermetallic compound, as described in claim 1, for a lithium-free secondary battery negative electrode.
5. The lithium electrodeposition induction layer has a thickness of 0.05 μm to 2 μm, as described in claim 1, for a lithium-free secondary battery negative electrode.
6. A method for producing a negative electrode for a lithium-free secondary battery according to any one of claims 1 to 5, comprising the step of electrically depositing copper and zinc onto a conductive metal layer using an electrolyte containing a copper precursor, a zinc precursor, and pyrophosphate.
7. The method for manufacturing a negative electrode for a lithium-free secondary battery according to claim 6, wherein the electrodeposition step is carried out by applying a voltage to an electrodeposition system comprising a working electrode containing the conductive metal layer; a relative electrode containing a copper-zinc alloy; and the electrolyte.
8. The method for producing a negative electrode for a lithium-free secondary battery according to claim 6, wherein the electrolyte is an aqueous solution containing a metal pyrophosphate at a concentration of 70 mM to 800 mM, a copper precursor at a concentration of 10 mM to 50 mM, and a zinc precursor at a concentration of 10 mM to 50 mM.
9. The method for manufacturing a negative electrode for a lithium-free secondary battery according to claim 6, further comprising the step of heat-treating the electrodeposited material at a temperature of 200°C or higher under a vacuum or inert gas atmosphere after the electrodeposited step.
10. Positive electrode containing positive electrode active material; A lithium-free secondary battery comprising a negative electrode according to any one of claims 1 to 5; and a separation membrane or electrolyte layer interposed between the positive electrode and the negative electrode.
11. The lithium-free secondary battery according to claim 10, further comprising a lithium metal layer that is electrodeposited onto the lithium electrodeposition induction layer of the negative electrode by charging the lithium-free secondary battery.

Description

[Cross-reference of related applications] This application claims priority rights based on Korean Patent Application No. 10-2023-0059728 dated 9 May 2023 and Korean Patent Application No. 10-2024-0053381 dated 22 April 2024, and all content disclosed in the documents of said Korean Patent Applications is incorporated herein by reference. This invention relates to a negative electrode for lithium-free secondary batteries, a method for manufacturing the same, and a lithium-free secondary battery, which can improve the electrochemical properties and lifespan characteristics of lithium-free secondary batteries. Lithium metal batteries utilize lithium metal (Li-metal) as the negative electrode active material. Compared to conventional batteries using graphite-based or lithium alloy-based negative electrodes, they theoretically offer significantly higher energy density and capacity. Therefore, research and development of such lithium metal batteries continue, as they are being applied to batteries requiring high energy density. However, lithium metal batteries have several drawbacks, including large volume changes in the negative electrode during charging and discharging, the growth of needle-shaped lithium metal layers (such as lithium dendrites), and, due to the highly reactive properties of lithium metal, side reactions between the lithium metal layer and the electrolyte, resulting in a large irreversible capacity. Consequently, lithium metal batteries have a high probability of electrode short circuits and insufficient stability and lifespan characteristics, and therefore have not yet been commercialized. Recently, as an alternative to the aforementioned lithium metal batteries, there has been growing research and interest in lithium-free secondary batteries (node-free secondary batteries) that form the negative electrode using the negative electrode current collector itself, without forming a separate lithium metal layer or other negative electrode active material layer on the negative electrode current collector. Such lithium-free secondary batteries can be defined as batteries that utilize lithium metal as the negative electrode active material by electrodepositing lithium onto the negative electrode current collector during charging. However, existing lithium-free secondary batteries, or those utilizing lithium metal as the negative electrode active material, still carry the risk of problems such as the uneven growth of lithium metal leading to the growth of lithium dendrites. To overcome these technical limitations, techniques have been reported such as fabricating current collectors with lithium-hydrophilic materials and increasing the surface area of the current collector to induce uniform lithium electrodeposition. However, the processes applied to the fabrication of current collectors containing lithium-friendly materials or three-dimensional current collectors with high surface area almost always suffer from disadvantages such as long process times, extremely high costs, and low mass production capabilities. Furthermore, these methods present additional problems, such as difficulty in fabricating thin current collectors and difficulty in fully utilizing the high energy density of lithium-free secondary batteries. This diagram schematically shows an example of an electro-deposition system used for manufacturing a negative electrode according to an embodiment of the present invention.Figures 2a and 2c are photographs of electron microscope analysis of the negative electrode surfaces formed in Comparative Example 2 (Figure 2a), Example 1 (Figure 2b), and Example 2 (Figure 2c), respectively.Figures 2a and 2c are photographs of electron microscope analysis of the negative electrode surfaces formed in Comparative Example 2 (Figure 2a), Example 1 (Figure 2b), and Example 2 (Figure 2c), respectively.Figures 2a and 2c are photographs of electron microscope analysis of the negative electrode surfaces formed in Comparative Example 2 (Figure 2a), Example 1 (Figure 2b), and Example 2 (Figure 2c), respectively.This photograph shows the changes in the film quality of the lithium electrodeposition induction layer before and after heat treatment during the manufacturing process of the negative electrode in Example 5, as analyzed by electron microscope.This graph shows the overvoltage evaluation results during lithium electrodeposition for half-cells including the negative electrodes of Comparative Example 1 and Example 2.This graph shows the results of evaluating the life characteristics of half-cells including the negative electrodes of Comparative Examples 1 and 2, and Examples 1 and 2. In this specification, when a part "includes" a component, unless otherwise stated, it means that it may include other components rather than excluding them. Terms of degree used throughout this specification, such as “approximately,” “substantially,” etc., are used with respect to the manufacturing and material tolerances inherent