Lithium battery

Patent metadata

Field	Value
Publication number	US-11942593-B2
Application number	US-202117545036-A
Country	US
Kind code	B2
Filing date	Dec 8, 2021
Priority date	Jul 27, 2018
Publication date	Mar 26, 2024
Grant date	Mar 26, 2024

Abstract

Provided herein is a lithium battery including: a cathode including a cathode active material; an anode including an anode active material; an electrolyte between the cathode and the anode; and a separator impregnated with the electrolyte, wherein the separator includes carboxyl group-containing microbial cellulose nanofibers, and wherein a differential scanning calorimetry (DSC) thermogram of the separator evinces an exothermic reaction peak, represented by a differential value (dH/dT), at a temperature in a range of about 150° C. to about 200° C.

First claim

What is claimed is:

1. A lithium battery comprising:
a cathode comprising a cathode active material;
an anode comprising an anode active material;
an electrolyte disposed between the cathode and the anode; and
a separator impregnated with the electrolyte,
wherein the separator comprises cellulose nanofibers, and
wherein a differential scanning calorimetry (DSC) thermogram of the separator impregnated with the electrolyte does not show an exothermic reaction peak as represented by a differential value (dH/dT) within a temperature range of about 150° C. to about 200° C.,
wherein the cellulose nanofibers comprise carboxyl group-containing microbial cellulose nanofibers,
wherein the carboxyl group of the carboxyl group-containing microbial cellulose nanofibers is bound to a carbon atom of a pyranose ring and is represented by Formula a or b below:
—R 1 —O—R 2 —COOM  <Formula a>

—O—R 2 —COOM,  <Formula b>

wherein R 1 and R 2 are each independently a substituted or unsubstituted C 1 -C 10 alkylene group, and M is hydrogen or an alkali metal.

2. The lithium battery of claim 1 , wherein the separator impregnated with the electrolyte has a crystalline index after exposure to heat at 170° C. for 3 hours under an inert atmosphere that is 50% or more of the crystalline index of the separator before the heat exposure, wherein the crystalline index of the separator is expressed as an intensity ratio ((I 002 −I AM )/I 002 ) of a crystalline peak intensity (I 002 −I AM ) to a total peak intensity I 002 of a (002) crystal plane in an X-ray diffraction (XRD) spectrum, and the crystalline peak intensity is a difference between the total peak intensity I 002 of the (002) crystal plane and a peak intensity lane of an amorphous phase.

3. The lithium battery of claim 1 , wherein, after the separator impregnated with the electrolyte is exposed to heat at 170° C. for 3 hours under an inert atmosphere, no carbonized areas are visible on a surface of the separator.

4. The lithium battery of claim 1 , wherein the electrolyte comprises at least one selected from an ionic metal complex represented by Formula 1 and a lithium salt containing a sulfonyl group (—S(═O) 2 —):

wherein, in Formula 1, Me is an element selected from transition metals and elements belonging to groups 13 to 15 of the Periodic Table;
M is a metal ion;
a is an integer of 1 to 3, b is an integer of 1 to 3, and s is an integer equal to the value obtained by dividing b by a;
p is 0 to 8, g is 0 or 1, and r is 1 to 4;
X 1 and X 2 are each independently O, S, or NR a ;
R 1 and R a are each independently a halogen, a C 1 -C 5 alkyl group unsubstituted or substituted with one or more halogens, or a C 1 -C 5 aryl group unsubstituted or substituted with one or more halogens; and
R 2 is a C 1 -C 5 alkylene group unsubstituted or substituted with a halogen, or a C 1 -C 5 arylene group unsubstituted or substituted with one or more halogens.

5. The lithium battery of claim 4 , wherein the ionic metal complex is represented by Formula 2:

wherein, in Formula 2, Me is Al, B, or P;
M is a metal ion;
p is 0 to 8, g is 0 or 1, and r is 1 to 4;
X 3 and X 4 are independently O or S;
R 3 is halogen; and
R 4 is a C 1 -C 5 alkylene group unsubstituted or substituted with one or more halogens, or a C 1 -C 5 arylene group unsubstituted or substituted with one or more halogens.

6. The lithium battery of claim 4 , wherein the ionic metal complex is represented by Formula 3 or 4:

wherein, in Formulae 3 and 4,
Me is Al, B, or P;
p is 0 to 8, and r is 1 to 4;
R 5 is a halogen; and
R 6 is a C 1 -C 5 alkylene group unsubstituted or substituted with one or more halogens.

7. The lithium battery of claim 4 , wherein the ionic metal complex is represented by one of Formulae 5 to 10:

8. The lithium battery of claim 4 , wherein the lithium salt containing the sulfonyl group is LiCF 3 SO 3 , LiC 4 F 9 SO 3 , Li(CF 3 SO 2 ) 2 N, Li(C 2 F 5 SO 2 ) 2 N, Li(FSO 2 ) 2 N, Li(CF 3 SO 3 ) 2 N, or LiN(C x F 2X+1 SO 2 )(C y F 2y+1 SO 2 ) wherein x and y are each independently an integer of 3 to 10.

9. The lithium battery of claim 4 , wherein a content of at least one selected from the ionic metal complex and the lithium salt containing the sulfonyl group is about 0.01 M to about 5 M based on a total weight of the electrolyte.

10. The lithium battery of claim 1 , wherein the electrolyte comprises an organic solvent.

11. The lithium battery of claim 10 , wherein the organic solvent includes at least one selected from the group comprising propylene carbonate, ethylene carbonate, fluoroethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, dibutyl carbonate, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, γ-butyrolactone, dioxolane, 4-methyldioxolane, N,N-dimethylformamide, dimethylacetamide, dimethylsulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, diethylene glycol, and dimethyl ether.

12. The lithium battery of claim 1 , wherein a content of a carboxyl group in the carboxyl group-containing cellulose nanofibers is 0.02 mmol/g to 10 mmol/g.

13. The lithium battery of claim 1 , wherein an average diameter of the carboxyl-group-containing cellulose nanofibers is about 45 nm or less.

14. The lithium battery of claim 1 , wherein a full width at half maximum (FWHM) in a diameter distribution graph of the carboxyl-group-containing cellulose nanofibers is about 50 nm or less.

15. The lithium battery of claim 1 , wherein the carboxyl-group-containing microbial cellulose has an absorption peak near 1572 cm −1 in an IR spectrum.

16. The lithium battery of claim 1 , wherein the separator further comprises wood-based cellulose nanofibers.

17. The lithium battery of claim 1 , wherein the separator has a tensile modulus of about 200 kgf/cm 2 to about 1000 kgf/cm 2 .

18. The lithium battery of claim 1 , wherein the separator has a pin-puncture strength of about 30 kgf/cm 2 to about 150 kgf/cm 2 .

19. The lithium battery of claim 1 , wherein the separator has a porosity of about 10% to about 90%.

20. The lithium battery of claim 1 , wherein the separator has an air permeability of about 50 seconds/100 cc to about 800 seconds/100 cc.

21. The lithium battery of claim 1 , wherein the separator has a contact angle with water at 20° C. of about 60° or less.

22. The lithium battery of claim 1 , wherein thermal shrinkage of the separator after incubating the porous film at 150° C. for 30 minutes is about 5% or lower.

23. The lithium battery of claim 1 , wherein the separator further comprises at least one selected from a cross-linking agent and a binder.

24. The lithium battery of claim 1 , wherein the carboxyl group-containing microbial cellulo

Assignees

• Samsung Electronics Co Ltd

Inventors

• Gwon Hyeokjo
• Kang Jinkyu
• Park Kitae
• Lee Hyunchul
• Kim Ryounghee
• Do Euncheol
• Park Soojin
• Ji Sangmin

Classifications

• H01M10/052 Primary

  Li-accumulators · CPC title

• H01M10/0567

  characterised by the additives · CPC title

• H01M50/417

  Polyolefins · CPC title

• H01M50/429

  Natural polymers · CPC title

• H01M50/44

  Fibrous material · CPC title