# US 9,040,197 B2 · Electrode structure and method for making the same

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- Number: US 9,040,197 B2
- Document ID: US9040197B2
- Status: Granted
- Kind: B2
- Application number: 13/850,437
- Filed: 2013-03-26
- Published: 2013-08-22
- Granted: 2015-05-26
- Earliest claimed: 2011-10-13
- Assignees: Sion Power Corporation
- Applicants: Sion Power Corporation
- Inventors: John D. Affinito; Gregory K. Lowe
- Web page: https://patentgrep.com/patent/US9040197B2

## CPC

- H01M 4/382: {Lithium (H01M4/405 takes precedence)}
- C23C 14/00: Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C 14/0641: {Nitrides (C23C14/0617 takes precedence)}
- H01M 4/0426: {Sputtering}
- H01M 4/13: Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M 4/134: Electrodes based on metals, Si or alloys
- H01M 4/1395: of electrodes based on metals, Si or alloys
- H01M 4/366: {as layered products}
- H01M 10/052: Li-accumulators
- H01M 10/056: characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M 10/0565: Polymeric materials, e.g. gel-type or solid-type
- Y02E 60/10: Energy storage using batteries
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- 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
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

Electrode structures, and more specifically, electrode structures for use in electrochemical cells, are provided. The electrode structures described herein may include one or more protective layers. In one set of embodiments, a protective layer may be formed by exposing a lithium metal surface to a plasma comprising ions of a gas to form a ceramic layer on top of the lithium metal. The ceramic layer may be highly conductive to lithium ions and may protect the underlying lithium metal surface from reaction with components in the electrolyte. In some cases, the ions may be nitrogen ions and a lithium nitride layer may be formed on the lithium metal surface. In other embodiments, the protective layer may be formed by converting lithium to lithium nitride at high pressures. Other methods for forming protective layers are also provided.

## Claims

### Claim 1

An article for use in an electrochemical cell, comprising:
a composite structure having a first side and a second, opposing side, the composite structure comprising:
at the first side, a predominantly lithium metal electroactive portion;
at the second side, a predominantly lithium nitride portion, wherein
at a location at least 10 microns from the first side toward the second side, the composite structure is free of Li3N or has a molar ratio of Li metal to Li3N of greater than 5:1, and
at a location at least 1 micron from the second side toward the first side, the composite structure has a molar ratio of Li metal to Li3N of less than 1:1000 and a lithium ion conductivity of at least 1×10−4 S/cm, and
a gradient region comprising both lithium metal and Li3N between the first side and the second side, the gradient region having a thickness of at least 0.005 microns;
an electrolyte layer adjacent the lithium nitride portion, wherein the electrolyte layer has a yield strength of greater than 50 N/cm2, and
wherein the article is under an applied anisotropic force, the anisotropic force having a component normal to a surface of the article, wherein the component defines a pressure of at least 80 N/cm2.

### Claim 2 (depends on 1)

An article of claim 1, wherein the article is under an applied anisotropic force, the anisotropic force having a component normal to a surface of the article, wherein the component defines a pressure of at least 160 N/cm2.

### Claim 3 (depends on 1)

An article of claim 1, wherein the lithium nitride portion is substantially impermeable to liquids.

### Claim 4 (depends on 1)

An article of claim 1, wherein the lithium nitride portion comprises pores.

### Claim 5 (depends on 4)

An article of claim 4, wherein at least a portion of the pores of the lithium nitride portion are filled, partially or completely, with a polymer.

### Claim 6 (depends on 1)

An article of claim 1, further comprising a polymer layer adjacent the lithium nitride portion.

### Claim 7 (depends on 1)

An article of claim 1, wherein the lithium metal portion has a thickness of at least 5 microns.

### Claim 8 (depends on 1)

An article of claim 1, wherein the lithium metal is doped with a metal.

### Claim 9 (depends on 1)

An article of claim 1, wherein the lithium metal portion is formed at least in part by condensing lithium vapor onto a substrate in the presence of a gaseous material to co-deposit the electroactive portion.

### Claim 10 (depends on 9)

An article of claim 9, wherein the gaseous material is selected from one or more of the group consisting of carbon dioxide, acetylene, nitrogen, nitrous oxide, nitrogen dioxide, ethylene, sulfur dioxide, hydrocarbons, alkyl phosphate esters, alkyl sulfite esters, and alkyl sulfate esters.

### Claim 11 (depends on 10)

An article of claim 10, wherein the gaseous material is nitrous oxide.

### Claim 12 (depends on 1)

An article of claim 1, further comprising a cathode comprising sulfur as an active cathode species.

### Claim 13 (depends on 12)

An article of claim 12, wherein the sulfur is elemental sulfur.

### Claim 14 (depends on 1)

An article of claim 1, wherein the electrolyte layer comprises a polymer gel and a lithium salt.

### Claim 15 (depends on 1)

An article of claim 1, wherein the electrolyte layer has a lithium ion conductivity of at least 1×10−4 S/cm.

### Claim 16 (depends on 1)

An article of claim 1, wherein the electrolyte layer has a yield strength of greater than 160 N/cm2.

### Claim 17 (depends on 1)

An article of claim 1, wherein the electrolyte layer has a yield strength of greater than 80 N/cm2.

### Claim 18 (depends on 1)

An article of claim 1, wherein the electrolyte layer has a yield strength greater than a yield strength of lithium metal.

### Claim 19 (depends on 1)

An article of claim 1, wherein the electrolyte layer has a yield strength of greater than 2 times the normal component of the pressure applied to the article.

### Claim 20 (depends on 1)

An article of claim 1, wherein the yield strength of the electrolyte layer is less than 20 times the normal component of the pressure applied to the article.

### Claim 21 (depends on 1)

An article of claim 1, further comprising a separator adjacent the electrolyte layer.

### Claim 22

An article for use in an electrochemical cell, comprising:
a composite structure comprising:
a lithium metal electroactive portion present at a first side of the composite structure, the lithium metal electroactive portion having a thickness of at least 10 microns;
a lithium nitride portion present at a second side of the composite structure, the lithium nitride portion having a thickness of greater than 1 micron and a lithium ion conductivity of at least 1×10−4 S/cm; and
a gradient region comprising both lithium metal and Li3N between the first side and the second side, the gradient region having a thickness of at least 0.005 microns;
an electrolyte layer adjacent the lithium nitride portion, wherein the electrolyte layer has a yield strength of greater than 50 N/cm2, and
wherein the article is under an applied anisotropic force, the anisotropic force having a component normal to a surface of the article, wherein the component defines a pressure of at least 80 N/cm2.

### Claim 23 (depends on 22)

An article of claim 22, wherein the lithium nitride portion is substantially impermeable to liquids.

### Claim 24 (depends on 22)

An article of claim 22, wherein the lithium nitride portion comprises pores.

### Claim 25 (depends on 24)

An article of claim 24, wherein at least a portion of the pores of the lithium nitride portion are filled, partially or completely, with a polymer.

### Claim 26 (depends on 22)

An article of claim 22, further comprising a cathode comprising sulfur as an active cathode species.

### Claim 27 (depends on 26)

An article of claim 26, wherein the sulfur is elemental sulfur.