Negative electrode active material for secondary batteries having improved lifespan characteristics

Patent metadata

Field	Value
Publication number	US-10439208-B2
Application number	US-201414892872-A
Country	US
Kind code	B2
Filing date	Jul 24, 2014
Priority date	Jul 31, 2013
Publication date	Oct 8, 2019
Grant date	Oct 8, 2019

Abstract

Disclosed is a negative electrode active material for secondary batteries having improved lifespan characteristics. In particular, provided is a negative electrode active material, for secondary batteries, including silicon (Si), and amorphous hard carbon or low-crystalline soft carbon.

First claim

The invention claimed is:

1. A negative electrode active material for secondary batteries, the negative electrode active material consisting of silicon (Si), and low-crystalline soft carbon,
wherein the silicon is dispersed on surfaces of the low-crystalline soft carbon,
wherein the low-crystalline soft carbon is formed from a carbon precursor comprising at least one selected from the group consisting of sucrose, methylene diphenyl diisocyanate, polyurethane, polyvinyl alcohol, polyvinylchloride, furfuryl alcohol, polyacrylonitrile, polyamide, furan resin, cellulose, styrene, polyimide, epoxy resin, vinyl chloride resin, coal tar pitch, petroleum based pitch, mesophase pitch, and tar, and
wherein the negative electrode active material consists of 2 wt% to 40 wt% of silicon, and 60 wt% to 98 wt% of low-crystalline soft carbon.

2. The negative electrode active material according to claim 1 , wherein the low-crystalline soft carbon has a capacity of 350 mAh/g to 500 mAh/g.

3. The negative electrode active material according to claim 1 , wherein the silicon is dispersed on a surface of the low-crystalline soft carbon by mixing a mixture, which comprises a viscoelastic polymer, with the low-crystalline soft carbon, and by thermally treating the same.

4. The negative electrode active material according to claim 3 , wherein the negative electrode active material is thermally treated at 800 ° C. to 1200 ° C.

5. The negative electrode active material according to claim 1 , wherein the silicon is a nanoparticle type.

6. The negative electrode active material according to claim 5 , wherein a size of the silicon nanoparticles is 5 nanometers to 30 nanometers.

7. The negative electrode active material according to claim 1 , wherein the silicon has a nanowire shape.

8. The negative electrode active material according to claim 7 , wherein a diameter of the silicon nanowire is 10 nanometers to 500 nanometers, and a length of the silicon nanowire is 20 nanometers to 1000 nanometers.

9. The negative electrode active material according to claim 7 , wherein the silicon nanowire is dispersed to a spiral structure on a surface of the low-crystalline soft carbon.

10. A negative electrode comprising the negative electrode active material according to claim 1 .

11. The negative electrode according to claim 10 , wherein the negative electrode has an energy density of 1.0 mAh/cm 2 to 9.0 mAh/cm 2.

12. A secondary battery according to claim 10 , wherein an electrode assembly, which comprises the negative electrode according to claim 10 , a positive electrode and a separator disposed between the negative electrode and the positive electrode, is impregnated with an electrolyte solution.

13. The secondary battery according to claim 12 , wherein the positive electrode comprises a lithium transition metal oxide represented by Formula 1 or 2 below as a positive electrode active material:
Li x M y Mn 2-y O 4-z A z   (1),

wherein M is at least one element selected from the group consisting of Al, Mg, Ni, Co, Fe, Cr, V, Cu, B, Ca, Zn, Zr, Nb, Mo, Sr, Sb, W, Ti and Bi; and
A is at least one monovalent or divalent anion; 0.9≤x ≤1.2, 0 < y<2, and 0 ≤z<0.2,
(1-x)LiM'O 2-y A y -xLi 2 MnO 3-3 , , A y ,   (2),

wherein M′ is Mn a M b ;
M is at least one selected from the group consisting of Ni, Ti, Co, Al, Cu, Fe, Mg, B, Cr, Zr, Zn and Period II transition metals;
A is at least one selected from the group consisting of anions such as PO 4 , BO 3 , CO 3 , F and NO 3 ; and
0<x<1, 0<y ≤0.02, 0<y′≤0.02, 0.5 ≤a ≤1.0, 0 ≤b ≤0.5, and a+b=1.

14. The secondary battery according to claim 12 , wherein the secondary battery is a lithium ion battery, a lithium ion polymer battery or a lithium polymer battery.

15. A battery module comprising the secondary battery according to claim 12 as a unit cell.

16. A battery pack comprising the battery module according to claim 15 .

17. A device comprising the battery pack according to claim 16 as a power source.

18. The device according to claim 17 , wherein the device is an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle or a system for storing power.

Assignees

• Lg Chemical Ltd

Inventors

• Uhm In Sung
• Yoo Jungwoo
• Kim Je Young
• Hah Hoe Jin
• Kwon Ji Yoon

Classifications

• H01M4/366 Primary

  as layered products · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/62

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

• H01M10/052

  Li-accumulators · CPC title

• H01M2220/20

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