Electrolyte for lithium metal battery and lithium metal battery comprising same

Patent metadata

Field	Value
Publication number	US-2020203759-A1
Application number	US-201816643819-A
Country	US
Kind code	A1
Filing date	Oct 8, 2018
Priority date	Oct 17, 2017
Publication date	Jun 25, 2020
Grant date	—

Abstract

An electrolyte for a lithium metal battery and a lithium metal battery including the same, more specifically an electrolyte for a lithium metal battery including a lithium salt, an organic solvent and an additive, wherein the additive includes a functional group that binds to lithium metal at one end thereof and a fluorinated hydrocarbon group at the other end. The electrolyte for the lithium metal battery includes an additive including particular functional groups to improve the stability of the lithium metal and suppress the side reaction at the surface, thereby enabling the lithium metal battery to have high capacity, high stability, and long life.

First claim

1 . An electrolyte for a lithium metal battery comprising:
a lithium salt; an organic solvent and an additive, wherein the additive comprises a first end and a second end opposite the first end, wherein a functional group that binds to lithium metal is present at the first end and a fluorinated hydrocarbon group is present at the second end.

2 . The electrolyte for the lithium metal battery according to claim 1 , wherein the functional group that binds to the lithium metal comprises at least one selected from the group consisting of a thiol group, an amine group and a hydroxy group.

3 . The electrolyte for the lithium metal battery according to claim 1 , wherein the additive is represented by the following Formula 1:

wherein A is an alkyl group having 1 to 20 carbon atoms which is substituted or unsubstituted with fluorine; an alkenyl group having 2 to 20 carbon atoms which is substituted or unsubstituted with fluorine; an alkynyl group having 2 to 20 carbon atoms which is substituted or unsubstituted with fluorine; a cycloalkyl group having 3 to 20 carbon atoms which is substituted or unsubstituted with fluorine; or an aryl group having 6 to 40 carbon atoms which is substituted or unsubstituted with fluorine,
B is a single bond; an alkanediyl group having 1 to 10 carbon atoms which is substituted or unsubstituted with fluorine; an alkenediyl group having 2 to 10 carbon atoms which is substituted or unsubstituted with fluorine; an unsubstituted alkynediyl group having 2 to 10 carbon atoms; a cycloalkyl group having 3 to 20 carbon atoms which is substituted or unsubstituted with fluorine; or an arylene group having 6 to 40 carbon atoms which is substituted or unsubstituted with fluorine,
at least one of A and B is substituted with fluorine,
O is oxygen,
X is independently selected from a thiol group, an amine group or a hydroxy group,
m is 0 or 1, and
n is an integer of 1 to 3.

4 . The electrolyte for the lithium metal battery according to claim 1 , wherein the additive comprises at least one selected from the group consisting of 1H,1H2H,2H,3H,3H-perfluoroundecylthiol, 1H,1H,2H,2H-perfluorodecanethiol, 1H,1H,2H,2H-perfluorononanethiol, 1H,1H,2H,2H-perfluoro-1-octanethiol, 1H,1H-perfluorooctylthiol, 1H,1H-perfluoropropylthiol, 2,2,2-trifluoroethanethiol, 1H,1H,2H,2H-perfluoro-1-hexanethiol, 2,3,4,5,6-pentafluorothiophenol, 2,3,5,6-tetrafluorobenzenethiol, 2,4-difluorothiophenol, 3,4-difluorothiophenol, 2-fluorothiophenol, 3-fluorothiophenol, 4-fluorothiophenol, 2-(trifluoromethoxy)thiophenol, 3-(trifluoromethoxy)thiophenol, 2-(trifluoromethyl)benzenethiol, 2,6-difluorobenzyl mercaptan, 3,4-difluorobenzyl mercaptan, 3,5-difluorobenzyl mercaptan, 4-fluorobenzyl mercaptan, 3,5-bis(trifluoromethyl)benzenethiol, 4-trifluoromethylbenzyl mercaptan, 1H,1H-perfluorooctylamine, 1H,1H-heptafluorobutylamine, 1H,1H-perfluorononylamine, 4-(1H, 1H,2H,2H-perfluorodecyl)benzylamine, 2,2,3,3,4,4,4-heptafluorobutylamine, 2,2,3,3,3-pentafluoropropylamine, 3,3,3-trifluoropropylamine, 4-fluoro-α-methylbenzyl alcohol, 2-fluoro-3-methylbenzyl alcohol, 4-fluoro-3-methylbenzyl alcohol, 5-fluoro-2-methylbenzyl alcohol, 4-fluoro-3-nitrobenzyl alcohol, 2-fluoro-5-nitrobenzyl alcohol, 2-fluoro-3-(trifluoromethoxy)benzyl alcohol, 2-fluoro-3-nitrobenzyl alcohol, 2-fluoro-5-methoxybenzyl alcohol, 3-fluoro-5-(trifluoromethyl)benzyl alcohol, 3-fluoro-5-methoxybenzyl alcohol, 4-fluoro-3-(trifluoromethyebenzyl alcohol, 4-fluoro-3-methoxybenzyl alcohol, 5-fluoro-2-(trifluoromethyl)benzyl alcohol, 5-fluoro-2-nitrobenzyl alcohol, DL-4-fluoro-α-propylbenzyl alcohol, 3-fluorobenzyl alcohol and 4-fluorophenethyl alcohol.

5 . The electrolyte for the lithium metal battery according to claim 1 , wherein the additive is present in an amount of from 0.01% by weight to 5% by weight, based on a total weight of the electrolyte for the lithium metal battery.

6 . The electrolyte for the lithium metal battery according to claim 1 , wherein the lithium salt comprises at least one selected from the group consisting of LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiC 4 BO 8 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2 ) 2 NLi, (C 2 F 5 SO 2 ) 2 NLi, (SO 2 F) 2 NLi, (CF 3 SO 2 ) 3 CLi, lithium chloroborane, lithium lower aliphatic carboxylate having 4 or less carbon atoms, 4-phenyl lithium borate and lithium imide.

7 . A lithium metal battery comprising:
a positive electrode comprising a positive electrode active material; a negative electrode comprising lithium metal or lithium alloy; and the electrolyte according to claim 1 .

8 . The lithium metal battery according to claim 7 , wherein the positive electrode active material comprises at least one selected from the group consisting of an elemental sulfur and a sulfur-containing compound.

Assignees

• Lg Chemical Ltd

Inventors

• Kim Kihyun
• Shin Dongseok
• Yang Doo Kyung
• Jin Sun Mi
• Park Intae

Classifications

• H01M4/405

  Alloys based on lithium · CPC title

• H01M2300/0025

  Organic electrolyte · CPC title

• H01M4/60

  of organic compounds · CPC title

• H01M4/5815

  Sulfides · CPC title

• H01M4/382

  Lithium (H01M4/405 takes precedence) · CPC title