# US 10,312,501 B2 · Electrolyte and negative electrode structure

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- Number: US 10,312,501 B2
- Document ID: US10312501B2
- Status: Granted
- Kind: B2
- Application number: 14/954,181
- Filed: 2015-11-30
- Published: 2016-06-16
- Granted: 2019-06-04
- Earliest claimed: 2014-12-10
- Assignees: GM Global Technology Operations LLC
- Applicants: GM Global Technology Operations LLC
- Inventors: Li Yang; Mei Cai; Fang Dai; Qiangfeng Xiao; Mark W. Verbrugge
- Web page: https://patentgrep.com/patent/US10312501B2

## CPC

- H01M 4/0452: {from solutions}
- 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 10/0562: Solid materials
- H01M 10/0567: characterised by the additives
- H01M 10/0568: characterised by the solutes
- H01M 10/0569: characterised by the solvents
- H01M 2220/20: Batteries in motive systems, e.g. vehicle, ship, plane
- H01M 2220/30: Batteries in portable systems, e.g. mobile phone, laptop
- H01M 2300/0028: characterised by the solvent
- H01M 2300/0037: Mixture of solvents
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

An example electrolyte includes a solvent, a lithium salt, and an additive selected from the group consisting of a silane with at least one Si—H group; a fluorinated methoxysilane; a fluorinated chlorosilane; and combinations thereof. The electrolyte may be used in a method for making a solid electrolyte interface (SEI) layer on a surface of a lithium electrode. A negative electrode structure may be formed from the method.

## Claims

### Claim 1

An electrolyte for forming a protective solid electrolyte interface layer on a surface of an electrode for an electrochemical cell, the electrolyte comprising:
a solvent;
a lithium salt; and
an additive selected from the group consisting of a silane with at least one Si—H group; a fluorinated methoxysilane; a fluorinated chlorosilane; and combinations thereof,
wherein the silane with at least one Si—H group is selected from the group consisting of H—Si((CH2)xCH3)2—R-Anion− Li+ and H—Si((CH2)xCH3)2—O—R-Anion− Li+, wherein x ranges from 0 to 2, R is any element or organic group, and the anion is selected from the group consisting of PF5−, BF3−, bis(trifluoromethane sulfonyl)imide (TFSI−), bis(fluorosulfonyl)imide (FSI−), and fluorine-malonato(difluoro)borate ((F)MDFB−),
wherein the fluorinated chlorosilane is represented by a formula (CH3)xSiCly—(CH2)m—(CF2)n—CF3, wherein x is 1 and y is 2 or x is 2 and y is 1, m ranges from 0 to 2, and n ranges from 1 to 20,
wherein the fluorinated methoxysilane is selected from the group consisting of:

### Claim 2 (depends on 1)

The electrolyte as defined in claim 1 wherein the fluorinated chlorosilane is selected from the group consisting of:

### Claim 3 (depends on 1)

The electrolyte as defined in claim 1 wherein:
the solvent is selected from the group consisting of ethylene carbonate, propylene carbonate, butylene carbonate, fluoroethylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, methyl formate, methyl acetate, methyl propionate, γ-butyrolactone, γ-valerolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, ethoxymethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,2-diethoxyethane, ethoxymethoxyethane, tetraethylene glycol dimethyl ether (TEGDME), polyethylene glycol dimethyl ether (PEGDME), and mixtures thereof; and
the lithium salt is selected from the group consisting of lithium bis(trifluoromethylsulfonyl)imide (LiN(CF3SO2)2 or LiTFSI), LiNO3, LiPF6, LiBF4, LiI, LiBr, LiSCN, LiClO4, LiAlCl4, LiB(C2O4)2 (LiBOB), LiB(C6H5)4, LiBF2(C2O4) (LiODFB), LiN(SO2F)2 (LiFSI), LiPF3(C2F5)3 (LiFAP), LiPF4(CF3)2, LiPF4(C2O4) (LiFOP), LiPF3(CF3)3, LiSO3CF3, LiCF3SO3, LiAsF6, and combinations thereof.

### Claim 4

A negative electrode structure, comprising:
a negative electrode including lithium as an active material; and
a solid electrolyte interface (SEI) layer formed on a surface of the negative electrode, the SEI layer formed from a silane with at least one Si—H group; a fluorinated methoxysilane; a fluorinated chlorosilane; and combinations thereof,
wherein the silane with at least one Si—H group is selected from the group consisting of H—Si((CH2)xCH3)2—R-Anion− Li+ and H—Si((CH2)xCH3)2—O—R-Anion− Li+, wherein x ranges from 0 to 2, R is any element or organic group, and the anion is selected from the group consisting of PF5−, BF3−, bis(trifluoromethane sulfonyl)imide (TFSI−), bis(fluorosulfonyl)imide (FSI−), and fluorine-malonato(difluoro)borate ((F)MDFB−),
wherein the fluorinated chlorosilane is represented by a formula (CH3)xSiCly—(CH2)m—(CF2)n—CF3, where x is 1 and y is 2 or x is 2 and y is 1, m ranges from 0 to 2, and n ranges from 1 to 20, and
wherein the fluorinated methoxysilane is selected from the group consisting of:

### Claim 5 (depends on 4)

The negative electrode structure as defined in claim 4 wherein the fluorinated chlorosilane is selected from the group consisting of:

### Claim 6

A method for making a solid electrolyte interface (SEI) layer on a surface of a lithium electrode, the method comprising:
exposing the lithium electrode to an electrolyte including:
a solvent;
a lithium salt; and
an additive selected from the group consisting of a silane with at least one Si—H group; a fluorinated methoxysilane; a fluorinated chlorosilane; and combinations thereof,
wherein the silane with at least one Si—H group is selected from the group consisting of H—Si((CH2)xCH3)2—R-Anion− Li+ and H—Si((CH2)xCH3)2—O—R-Anion− Li+, wherein x ranges from 0 to 2, R is any element or organic group, and the anion is selected from the group consisting of PF5−, BF3−, bis(trifluoromethane sulfonyl)imide (TFSI−), bis(fluorosulfonyl)imide (FSI−), and fluorine-malonato(difluoro)borate ((F)MDFB−),
wherein the fluorinated chlorosilane is represented by a formula (CH3)xSiCly—(CH2)m—(CF2)n—CF3, wherein x is 1 and y is 2 or x is 2 and y is 1, m ranges from 0 to 2, and n ranges from 1 to 20, and
wherein the fluorinated methoxysilane is selected from the group consisting of:

### Claim 7 (depends on 6)

The method as defined in claim 6 wherein the lithium electrode is exposed to the electrolyte in an electrochemical cell, and wherein the method further comprises applying a voltage to the electrochemical cell.

### Claim 8 (depends on 7)

The method as defined in claim 7 wherein the electrochemical cell is a Li—Li symmetrical electrochemical cell, and the electrolyte solvent is selected from the group consisting of 1,3-dioxolane (DOL or DIOX), dimethoxyethane (DME), tetrahydrofuran, 2-methyltetrahydrofuran, 1,2-diethoxyethane, ethoxymethoxyethane, tetraethylene glycol dimethyl ether (TEGDME), polyethylene glycol dimethyl ether (PEGDME), ethylene carbonate (EC), propylene carbonate, butylene carbonate, fluoroethylene carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC), methyl formate, methyl acetate, methyl propionate, γ-butyrolactone, γ-valerolactone, and mixtures thereof.

### Claim 9 (depends on 7)

The method as defined in claim 7 wherein the electrochemical cell is a Li—S electrochemical cell, and the electrolyte solvent is selected from the group consisting of 1,3-dioxolane (DOL), dimethoxyethane (DME), tetrahydrofuran, 2-methyltetrahydrofuran, 1,2-diethoxyethane, ethoxymethoxyethane, tetraethylene glycol dimethyl ether (TEGDME), polyethylene glycol dimethyl ether (PEGDME), and mixtures thereof.

### Claim 10 (depends on 7)

The method as defined in claim 7 wherein the electrochemical cell is a lithium ion battery, and the electrolyte solvent is selected from the group consisting of ethylene carbonate (EC), propylene carbonate, butylene carbonate, fluoroethylene carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC), methyl formate, methyl acetate, methyl propionate, γ-butyrolactone, γ-valerolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, ethoxymethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, and mixtures thereof.

### Claim 11 (depends on 6)

The method as defined in claim 6 wherein the lithium electrode is exposed to the electrolyte outside of an electrochemical cell and wherein the electrolyte solvent is selected from the group consisting of 1,3-dioxolane (DOL or DIOX), dimethoxyethane (DME), tetrahydrofuran, 2-methyltetrahydrofuran, 1,2-diethoxyethane, ethoxymethoxyethane, tetraethylene glycol dimethyl ether (TEGDME), polyethylene glycol dimethyl ether (PEGDME), ethylene carbonate (EC), propylene carbonate, butylene carbonate, fluoroethylene carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC), methyl formate, methyl acetate, methyl propionate, γ-butyrolactone, γ-valerolactone, and mixtures thereof.

### Claim 12 (depends on 6)

The method as defined in claim 6 wherein the lithium salt is selected from the group consisting of LiClO4, LiAlCl4, LiI, LiBr, LiSCN, LiBF4, LiB(C6H5)4, LiAsF6, LiCF3SO3, LiN(FSO2)2 (LIFSI), LiN(CF3SO2)2 (LITFSI or lithium bis(trifluoromethylsulfonyl)imide), LiPF6, LiB(C2O4)2 (LiBOB), LiBF2(C2O4) (LiODFB), LiPF3(C2F5)3 (LiFAP), LiPF4(CF3)2, LiPF4(C2O4) (LiFOP), LiPF3(CF3)3, LiSO3CF3, LiNO3, and mixtures thereof.

### Claim 13 (depends on 1)

The electrolyte as defined in claim 1 wherein the R of the silane with at least one Si—H group is —(CH2)2—Si((CH2)xCH3)3—, where x is from 0 to 2.

### Claim 14 (depends on 4)

The negative electrode structure as defined in claim 4 wherein the R of the silane with at least one Si—H group is —(CH2)2—Si((CH2)xCH3)3—, where x is from 0 to 2.