Anode for lithium secondary battery including stable solid electrolyte interphase layer and electrolyte composition for manufacturing same

Patent metadata

Field	Value
Publication number	US-2023027597-A1
Application number	US-202217865284-A
Country	US
Kind code	A1
Filing date	Jul 14, 2022
Priority date	Jul 16, 2021
Publication date	Jan 26, 2023
Grant date	—

Abstract

An electrolyte composition for a lithium secondary battery includes a lithium salt comprising a nitrogen element, a first additive having a LUMO (lowest occupied molecular orbital) value lower than a LUMO value of the lithium salt, and a second additive having a LUMO value higher than the LUMO value of the lithium salt.

First claim

What is claimed is:

1 . An electrolyte composition for a lithium secondary battery, comprising:
a lithium salt comprising a nitrogen element; a first additive having a LUMO (lowest occupied molecular orbital) value lower than a LUMO value of the lithium salt; and a second additive having a LUMO value higher than the LUMO value of the lithium salt.

2 . The electrolyte composition of claim 1 , wherein the lithium salt comprises:
a first lithium salt comprising at least one of lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), LiPF 6 , LiBF 4 , LiSbF 6 , LiAsF 6 , LiN(SO 2 CF 3 ) 2 , LiN(SO 3 C 2 F 5 ) 2 , LiC 4 F 9 SO 3 , LiClO 4 , LiAlO 2 , LiAICl 4 , LiCl, LiI, or any combination thereof; and a second lithium salt comprising LiNO 3 .

3 . The electrolyte composition of claim 2 , wherein a concentration of the first lithium salt ranges from about 0.5 mol/L to about 3 mol/L.

4 . The electrolyte composition of claim 2 , wherein a concentration of the second lithium salt ranges from about 0.1 mol/L to about 2 mol/L.

5 . The electrolyte composition of claim 1 , wherein the LUMO value of the lithium salt ranges from about −2 eV to about −1 eV.

6 . The electrolyte composition of claim 1 , wherein the LUMO value of the first additive ranges from about −4 eV to about −3 eV.

7 . The electrolyte composition of claim 1 , wherein the first additive comprises at least one of lithium bis(oxalato)borate (LiBOB), lithium difluoro bis(oxalato)phosphate (LiDFBP), lithium fluoro(oxalate)borate (LiFOB), or any combination thereof.

8 . The electrolyte composition of claim 1 , wherein an amount of the first additive ranges from about 0.1 wt % to about 10 wt % with respect to the electrolyte composition.

9 . The electrolyte composition of claim 1 , wherein the LUMO value of the second additive ranges from about −1.5 eV to about 2 eV.

10 . The electrolyte composition of claim 1 , wherein the second additive comprises at least one of LiPF 6 , LiPO 2 F 2 , lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), or any combination thereof.

11 . The electrolyte composition of claim 1 , wherein an amount of the second additive ranges from about 0.1 wt % to about 10 wt % with respect to the electrolyte composition.

12 . The electrolyte composition of claim 1 , further comprising an organic solvent comprising at least one of dimethyl ether, 1,2-dimethoxyethane (DME), 1,3-dioxolane, diethylene glycol, tetraethylene glycol, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, or any combination thereof.

13 . An anode for a lithium secondary battery, comprising:
a lithium electrode; and a solid electrolyte interphase (SEI) layer comprising a first layer disposed on the lithium electrode, a second layer disposed on the first layer and a third layer disposed on the second layer, wherein the first layer comprises at least one of LiF, Li x PO y F z (0.1≤x≤1, 2≤y≤3, 1≤z≤2), or any combination thereof, the second layer comprises Li 3 N, and the third layer comprises at least one of LiF, Li x PO y F z (0.1≤x≤1, 2≤y≤3, 1≤z≤2), or any combination thereof, and wherein the SEI layer is derived from the electrolyte composition of claim 1 .

14 . A method of manufacturing a lithium secondary battery, comprising:
preparing a lithium ion battery comprising a cathode, an anode comprising a lithium electrode, a separator interposed between the cathode and the anode, and the electrolyte composition of claim 1 ; and forming a solid electrolyte interphase (SEI) layer on a surface of the anode by performing a formation process on the lithium ion battery, wherein the SEI layer comprises a first layer disposed on the anode, a second layer disposed on the first layer and a third layer disposed on the second layer, and the first layer comprises at least one of LiF, Li x PO y F z (0.1≤x≤1, 2≤y≤3, 1≤z≤1), or any combination thereof, the second layer comprises Li 3 N, and the third layer comprises at least one of LiF, Li x PO y F z (0.1≤x≤1, 2≤y≤3, 1≤z≤2), or any combination thereof.

15 . The method of claim 14 , wherein the formation process is performed by repeating charging and discharging 1 to 5 times under conditions of a current density of about 0.5 to about 1 mA/cm 2 and a capacity per unit area of about 3 to about 10 mAh/cm 2 .

Assignees

• Hyundai Motor Co Ltd
• Kia Corp
• Ulsan National Institute Of Science And Tech

Inventors

• Lee Ji Yong
• Song Jong Chan
• Choi Nam Soon
• Kang Da Young
• Han Seung Hee
• Kim Sae Hun
• Lee Min Young

Classifications

• H01M10/0569

  characterised by the solvents · CPC title

• H01M10/058

  Construction or manufacture · CPC title

• H01M2300/0054

  Halogenides · CPC title

• H01M10/0567 Primary

  characterised by the additives · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title