Electrolyte for rechargeable lithium battery and rechargeable lithium battery including the same

Patent metadata

Field	Value
Publication number	US-2024072303-A1
Application number	US-202218012630-A
Country	US
Kind code	A1
Filing date	Mar 30, 2022
Priority date	Jul 22, 2021
Publication date	Feb 29, 2024
Grant date	—

Abstract

Provided are an electrolyte for a rechargeable lithium battery and a rechargeable lithium battery including the same, the electrolyte including a non-aqueous organic solvent, a lithium salt, and an additive, wherein the additive is a composition including a first compound and a second compound, the first compound is a cesium salt compound, and the second compound includes a composition including a second compound represented by Chemical Formula 1 or Chemical Formula 2.
Details of the Chemical Formula 1 and Chemical Formula 2 are as described in the specification.

First claim

1 . An electrolyte for a rechargeable lithium battery, comprising
a non-aqueous organic solvent, a lithium salt, and an additive, wherein the additive is a composition including a first compound and a second compound, the first compound is a cesium salt compound, and the second compound is represented by Chemical Formula 1 or Chemical Formula 2:

wherein, in Chemical Formula 1,
X 1 and X 2 are each independently a halogen, or —O-L-R 1 ,
at least one of X 1 to X 2 is —O-L 1 -R 1 ,
wherein L 1 is a single bond or a substituted or unsubstituted C1 to C10 alkylene group, and
R 1 s are each independently a cyano group (—CN), a difluorophosphite group (—OPF 2 ), a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, a substituted or unsubstituted C2 to C10 alkynyl group, a substituted or unsubstituted C3 to C10 cycloalkyl group, a substituted or unsubstituted C3 to C10 cycloalkenyl group, a substituted or unsubstituted C3 to C10 cycloalkynyl group, or a substituted or unsubstituted C6 to C20 aryl group, and
when X 1 and X 2 are simultaneously —O-L 1 -R 1 ,
R 1 s are each independently present, or
two R 1 s are linked to form a substituted or unsubstituted monocyclic or polycyclic aliphatic heterocycle or a substituted or unsubstituted monocyclic or polycyclic aromatic heterocycle; and

wherein, in Chemical Formula 2,
L 3 to L 5 are each independently be a single bond, a substituted or unsubstituted C1 to C10 alkylene group or a substituted or unsubstituted C6 to C30 arylene group, and
Y 1 to Y 3 are each independently be a cyano group (—CN), a substituted or unsubstituted C6 to C30 aryl group or a substituted or unsubstituted C2 to C30 heterocyclic group.

2 . The electrolyte for the rechargeable lithium battery of claim 1 , wherein
an anion of the cesium salt compound is an imide-based anion or a phosphate-based anion.

3 . The electrolyte for the rechargeable lithium battery of claim 1 , wherein
the cesium salt compound is represented by Chemical Formula 3 or Chemical Formula 4:

wherein, in Chemical Formula 3 and Chemical Formula 4,
R 15 to R 22 are each independently a fluoro group or a C1 to C4 fluoroalkyl group substituted with at least one fluoro group.

4 . The electrolyte for the rechargeable lithium battery of claim 3 , wherein
Chemical Formula 3 is represented by Chemical Formula 3-1 or Chemical Formula 3-2:

5 . The electrolyte for the rechargeable lithium battery of claim 1 , wherein
Chemical Formula 4 is represented by Chemical Formula 4-1:

6 . The electrolyte for the rechargeable lithium battery of claim 1 , wherein
the first compound is included in an amount of 0.05 to 3.0 parts by weight based on 100 parts by weight of the electrolyte for the rechargeable lithium battery.

7 . The electrolyte for the rechargeable lithium battery of claim 1 , wherein
one of X 1 and X 2 in Chemical Formula 1 is a fluoro group, and the other is —O-L 1 -R 1 , wherein L 1 is a single bond or a substituted or unsubstituted C1 to C10 alkylene group, and R 1 is a cyano group (—CN) or a difluorophosphite group (—OPF 2 ).

8 . The electrolyte for the rechargeable lithium battery of claim 1 , wherein
the second compound is represented by Chemical Formula 1-1:

wherein, in Chemical Formula 1-1,
m is one of integers 1 to 5, and
R 2 is a cyano group (—CN) or a difluorophosphite group (—OPF 2 ).

9 . The electrolyte for the rechargeable lithium battery of claim 1 , wherein
each of X 1 and X 2 in Chemical Formula 1 are —O-L 1 -R 1 , and two L 1 s are each independently a single bond or a substituted or unsubstituted C1 to C10 alkylene group, and two R 1 s are each independently a substituted or unsubstituted C1 to C10 alkyl group, or two R 1 s are linked to form a substituted or unsubstituted monocyclic aliphatic heterocycle or polycyclic aliphatic heterocycle.

10 . The electrolyte for the rechargeable lithium battery of claim 1 , wherein
the second compound is represented by Chemical Formula 1-2:

wherein, in Chemical Formula 1-2,
L 6 is a substituted or unsubstituted C2 to C5 alkylene group.

11 . The electrolyte for the rechargeable lithium battery of claim 10 , wherein
Chemical Formula 1-2 is represented by Chemical Formula 1-2a or Chemical Formula 1-2b:

wherein, in Chemical Formula 1-2a and Chemical Formula 1-2b,
R 5 to R 14 are each independently hydrogen, a halogen group, or a substituted or unsubstituted C1 to C5 alkyl group.

12 . The electrolyte for the rechargeable lithium battery of claim 1 , wherein
L 3 to L 5 in Chemical Formula 2 are each independently a single bond or a substituted or unsubstituted C1 to C10 alkylene group.

13 . The electrolyte for the rechargeable lithium battery of claim 1 , wherein
Y 1 to Y 3 in Chemical Formula 2 are each independently a cyano group (—CN) or a substituted or unsubstituted C6 to C30 aryl group.

14 . The electrolyte for the rechargeable lithium battery of claim 1 , wherein
the second compound is any one selected from the compounds listed in Group 1:

15 . The electrolyte for the rechargeable lithium battery of claim 1 , wherein
the second compound is included in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the electrolyte for the rechargeable lithium battery.

16 . The electrolyte for the rechargeable lithium battery of claim 1 , wherein
the composition includes the first compound and the second compound in a weight ratio of 1:0.1 to 1:10.

17 . The electrolyte for the rechargeable lithium battery of claim 1 , wherein
the composition includes the first compound and the second compound in a weight ratio of 1:0.5 to 1:2.

18 . The electrolyte for the rechargeable lithium battery of claim 1 , wherein
the composition is included in an amount of 0.2 to 8 parts by weight based on 100 parts by weight of the electrolyte for the rechargeable lithium battery.

19 . A rechargeable lithium battery, comprising
a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and the electrolyte for the rechargeable lithium battery of claim 1 .

20 . The rechargeable lithium battery of claim 19 , wherein
the positive electrode active material is represented by Chemical Formula 7:
Li x M 1 y M 2 z M 3 1-y-z O 2-a X a   [Chemical Formula 7]

Assignees

• Samsung Sdi Co Ltd

Inventors

• Kim Minseo
• Lee Tae Jin
• Kim Sanghyung
• Woo Myungheui
• Park Hyejin
• Kim Dahyun
• Ryu Bokyung

Classifications

• H01M10/4235

  Safety or regulating additives or arrangements in electrodes, separators or electrolyte (H01M10/4242 takes precedence) · CPC title

• H01M10/0525 Primary

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

• H01M10/0567 Primary

  characterised by the additives · CPC title

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title