# US 2021/0242457 A1 · Negative electrode for lithium secondary battery, lithium secondary battery comprising same, and manufacturing method therefor

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- Number: US 2021/0242457 A1
- Document ID: US20210242457A1
- Status: Published application
- Kind: A1
- Application number: 17/255,670
- Filed: 2019-09-26
- Published: 2021-08-05
- Earliest claimed: 2018-10-31
- Assignees: LG Chem, Ltd.
- Applicants: LG Chem, Ltd.
- Inventors: Yeon Suk HONG; Ju Ri KIM
- Web page: https://patentgrep.com/patent/US20210242457A1

## CPC

- H01M 4/366: {as layered products}
- C23C 16/403: {of aluminium, magnesium or beryllium}
- C23C 16/405: {of refractory metals or yttrium}
- C23C 16/45525: {Atomic layer deposition [ALD]}
- C23C 16/45555: {applied in non-semiconductor technology}
- H01M 4/04: Processes of manufacture in general
- H01M 4/0404: {by coating on electrode collectors}
- H01M 4/0428: {Chemical vapour deposition}
- H01M 4/133: Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M 4/134: Electrodes based on metals, Si or alloys
- H01M 4/1393: of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M 4/1395: of electrodes based on metals, Si or alloys
- H01M 4/364: {as mixtures}
- H01M 4/382: {Lithium (H01M4/405 takes precedence)}
- H01M 4/483: {for non-aqueous cells (H01M4/485 takes precedence)}
- H01M 4/587: for inserting or intercalating light metals
- H01M 4/62: Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M 10/052: Li-accumulators
- H01M 10/058: Construction or manufacture
- H01M 4/131: Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
- H01M 4/1391: of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
- H01M 4/625: {Carbon or graphite}
- H01M 2004/021: {Physical characteristics, e.g. porosity, surface area}
- H01M 2004/027: {Negative electrodes}
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A negative electrode for a lithium secondary battery including a current collector; a negative electrode mixture layer disposed on at least one surface of the current collector; a lithium diffusion rate-controlling layer formed on a surface of the negative electrode mixture layer by atomic layer deposition opposite the current collector; and a lithium layer disposed on a surface of the lithium diffusion rate-controlling layer opposite the negative electrode mixture layer. A method for prelithiating the negative electrode for a lithium secondary battery and a method for manufacturing a lithium secondary battery comprising the negative electrode. The negative electrode includes a lithium diffusion rate-controlling layer between a lithium thin film and a negative electrode mixture layer, and thereby can control the lithium diffusion rate during a prelithiation process and inhibit lithium loss or side reactions of lithium, thus enhancing cycle characteristics.

## Claims

### Claim 1

A negative electrode for a lithium secondary battery, comprising:
a current collector;
a negative electrode mixture layer formed on at least one surface of the current collector;
a lithium diffusion rate control layer formed on a surface of the negative electrode mixture layer by atomic layer deposition opposite the current collector; and
a lithium layer formed on a surface of the lithium diffusion rate control layer opposite the negative electrode mixture layer.

### Claim 2 (depends on 1)

The negative electrode of claim 1, wherein the lithium diffusion rate control layer controls diffusion of lithium from the lithium layer to the negative electrode mixture layer until injection of an electrolyte.

### Claim 3 (depends on 1)

The negative electrode of claim 1, wherein the lithium diffusion rate control layer controls diffusion of lithium from the lithium layer to the negative electrode mixture layer until a first charge/discharge.

### Claim 4 (depends on 1)

The negative electrode of claim 1, wherein a thickness of the lithium diffusion rate control layer is 0.1 nm to 100 nm.

### Claim 5 (depends on 1)

The negative electrode of claim 1, wherein a thickness of the lithium diffusion rate control layer is 0.5 nm to 50 nm.

### Claim 6 (depends on 1)

The negative electrode of claim 1, wherein the negative electrode mixture layer comprises at least one compound selected from the group consisting of SiOx, wherein 0<x≤2 SnO and SnO2.

### Claim 7 (depends on 1)

The negative electrode of claim 1, wherein the lithium diffusion rate control layer includes comprises at least one or two or more selected from the group consisting of Al2O3, TiO2, ZrO2, HfO2, Ta2O5, Nb2O5, Y2O3, MbO, CeO2, SiO2, La2O3, Ln2O3, Lu2O3, PrAlO3, Er2O3, HfAlO, HfSiO, ZrSiO, ZrAlO, HfON, HfSiON, SrTiO3, BaTiO3, BST and laminates.

### Claim 8 (depends on 1)

The negative electrode of claim 1, wherein the lithium diffusion rate control layer comprises Al2O3.

### Claim 9 (depends on 1)

The negative electrode of claim 1, wherein a thickness ratio of the lithium diffusion rate control layer and the lithium layer is 1:100 to 1:20000.

### Claim 10

A method for manufacturing a lithium secondary battery, the method comprising:
a first step of forming a negative electrode mixture layer on a current collector;
a second step of forming a lithium thin film layer on a surface of a release plate;
a third step of forming a lithium diffusion rate control layer by repeating an atomic layer deposition process of introducing a metal oxide on the lithium thin film layer;
a fourth step of preparing a negative electrode by stacking products of the first step and the third step, wherein the negative electrode mixture layer and the lithium diffusion rate control layer face each other;
a fifth step of manufacturing an electrode assembly comprising the negative electrode prepared in the fourth step; and
a sixth step of injecting an electrolyte into the electrode assembly manufactured in the fifth step.

### Claim 11

A method for manufacturing a lithium secondary battery, the method comprising:
a first step of forming a negative electrode mixture layer on a current collector;
a second step of forming a lithium diffusion rate control layer by repeating an atomic layer deposition process of introducing a metal oxide on the negative electrode mixture layer;
a third step of manufacturing a negative electrode by laminating a lithium thin film on the lithium diffusion rate control layer;
a fourth step of manufacturing an electrode assembly comprising the negative electrode prepared in the third step; and
a fifth step of injecting an electrolyte into the electrode assembly.

### Claim 12 (depends on 10)

The method of claim 10, wherein the atomic layer deposition process is performed until the thickness of the lithium diffusion rate control layer ranges from 0.1 nm to 100 nm.

### Claim 13 (depends on 10)

The method of claim 10, wherein the atomic layer deposition process is performed until the thickness of the lithium diffusion rate control layer ranges from 0.5 nm to 50 nm.

### Claim 14 (depends on 10)

The method of claim 10, wherein the third step comprises:
a step of positioning the release plate having the lithium thin film layer formed in the second step in a chamber;
a step of supplying metal atoms into the chamber;
a step of supplying a purge gas into the chamber;
a step of supplying an oxidant into the chamber to form a metal oxide layer on the surface of the lithium thin film layer; and
a step of supplying the purge gas into the chamber to remove unreacted oxidant.

### Claim 15 (depends on 11)

The method of claim 11, wherein the second step comprises:
a step of positioning the current collector having the negative electrode mixture layer formed in the first step in a chamber;
a step of supplying metal atoms into the chamber;
a step of supplying a purge gas into the chamber;
a step of supplying an oxidant into the chamber to form a metal oxide layer on the surface of the negative electrode mixture layer; and
a step of supplying the purge gas into the chamber to remove unreacted oxidant.