Surface-coated positive electrode active material particles and secondary battery comprising the same

Patent metadata

Field	Value
Publication number	US-10879529-B2
Application number	US-201716079247-A
Country	US
Kind code	B2
Filing date	Mar 21, 2017
Priority date	Mar 21, 2016
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

The present invention relates to surface-coated positive electrode active material particles and a secondary battery including the same, and specifically, it provides surface-coated positive electrode active material particles including positive electrode active material particles and a coating layer applied on a surface of the positive electrode active material particles, wherein the coating layer includes a polyimide comprising one or more structures selected from the group consisting of pyrrole, aniline, and carbazole. The surface-coated positive electrode active material particles according to the present invention includes a coating layer including a polyimide and metal ions; and since a direct contact between the positive electrode active material particles and an electrolyte can be prevented, a side reaction therebetween can be inhibited, and both excellent lithium ion mobility and excellent electron conductivity can be exhibited. Accordingly, a secondary battery with improved battery life and cycle characteristics at high-voltage and high-temperature conditions can be obtained.

First claim

The invention claimed is:

1. Surface-coated positive electrode active material particles comprising:
positive electrode active material particles; and
a coating layer applied on a surface of the positive electrode active material particles,
wherein the coating layer includes a polyimide comprising one or more structures selected from the group consisting of pyrrole, aniline, and carbazole, and
wherein the coating layer has a thickness of 1 to 200 nm.

2. The surface-coated positive electrode active material particles according to claim 1 , wherein the coating layer includes metal ions.

3. The surface-coated positive electrode active material particles according to claim 1 , wherein the polyimide included in the coating layer includes aniline.

4. The surface-coated positive electrode active material particles according to claim 2 , wherein the polyimide and the metal ions included in the coating layer are in a state in which the metal ions are captured by unshared electrons present in a nitrogen atom of aniline in the polyimide.

5. The surface-coated positive electrode active material particles according to claim 4 , wherein the unshared electrons present in a nitrogen atom of aniline have been generated as NH dissociates to release the H as H + .

6. The surface-coated positive electrode active material particles according to claim 1 , wherein the polyimide is represented by Chemical Formula 4 and has been produced by a condensation polymerization of pyromellitic dianhydride (PMDA) and 4,4′-iminodianiline (IDA).

7. The surface-coated positive electrode active material particles according to claim 2 , wherein the metal ions are ions of one or more metals selected from the group consisting of magnesium, aluminum, zirconium, and lithium.

8. The surface-coated positive electrode active material particles according to claim 2 , wherein the metal ions are included in an amount of 3 parts by weight or less with respect to 100 parts by weight of the polyimide.

9. The surface-coated positive electrode active material particles according to claim 1 , wherein the polyimide is included in an amount of 0.05 part by weight to 5 parts by weight with respect to 100 parts by weight of the positive electrode active material particles.

10. The surface-coated positive electrode active material particles according to claim 1 , wherein the positive electrode active material particles comprise one or more selected from the group consisting of oxides represented by Chemical Formulas 1 to 3, and V 2 O 5 , TiS, and MoS:
Li 1+x [Ni a Co b Mn c ]O 2   <Chemical Formula 1>

(−0.5≤x≤0.6, 0≤a, b, c≤1, and x+a+b+c=1);
LiMn 2−x M x O 4   <Chemical Formula 2>

(M is one or more elements selected from the group consisting of Ni, Co, Fe, P, S, Zr, Ti, and Al, and 0≤x≤2);
Li 1+a Fe 1−x M x (PO 4−b )X b   <Chemical Formula 3>

(M is one or more elements selected from the group consisting of Al, Mg, Ni, Co, Mn, Ti, Ga, Cu, V, Nb, Zr, Ce, In, Zn, and Y, X is one or more elements selected from the group consisting of F, S, and N, and −0.5≤a≤+0.5, 0≤x≤0.5, and 0≤b≤0.1).

11. A method of producing surface-coated positive electrode active material particles of claim 1 , the method comprising:
preparing a mixed solution by mixing a polyamic acid including one or more structures selected from the group consisting of pyrrole, aniline, and carbazole with an organic solvent (process 1);
dispersing positive electrode active material particles in the mixed solution to form a coating layer including the polyamic acid on a surface of the positive electrode active material particles (process 2); and
carrying out an imidation of the positive electrode active material particles including the coating layer applied thereon (process 3).

12. The method according to claim 11 , which forms a coating layer including a polyamic acid and additional metal ions through the process 2 by mixing the polyamic acid and the additional metal ions with the organic solvent during the process 1.

13. The method according to claim 12 , wherein the metal ions have been generated from a metal ion precursor,
wherein the metal ion precursor is one or more selected from the group consisting of an inorganic acid salt, an organic acid salt, and a metal complex of the metal ions.

14. The method according to claim 13 , wherein the inorganic acid salt of the metal ions is one selected from the group consisting of magnesium nitrate, zirconium sulfate, and a mixture thereof.

15. The method according to claim 11 , wherein the polyamic acid is produced by reacting a same equivalent amount of an aromatic anhydride and a diamine.

16. The method according to claim 15 , wherein at least one of the aromatic anhydride and the diamine include one or more structures selected from the group consisting of pyrrole, aniline, and carbazole.

17. The method according to claim 15 , wherein the diamine is 4,4′-iminodianiline.

18. The method according to claim 11 , wherein the polyamic acid is used in an amount of 0.1 part by weight to 1 part by weight with respect to 100 parts by weight of the organic solvent.

19. A secondary battery comprising:
a positive electrode including a positive electrode mixture including the surface-coated positive electrode active material particles according to claim 1 applied thereon;
a negative electrode; and
a separator interposed between the positive electrode and the negative electrode.

Assignees

• Lg Chemical Ltd

Inventors

• Jang Wook
• Cho Seung Beom
• Park Jin Young
• Kim Kyung Jun
• Ahn Jun Seong

Classifications

• H01M2220/20

  Batteries in motive systems, e.g. vehicle, ship, plane · CPC title

• H01M10/0525

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

• H01M4/62 Primary

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M4/366 Primary

  as layered products · CPC title