Electrode for secondary battery having improved energy density and lithium secondary battery including the same

Patent metadata

Field	Value
Publication number	US-9991507-B2
Application number	US-201414787154-A
Country	US
Kind code	B2
Filing date	Jul 25, 2014
Priority date	Jul 26, 2013
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

Disclosed are an electrode for a secondary battery having improved energy density and a lithium secondary battery including the same. More particularly, an electrode for a secondary battery, in which an electrode mix including an electrode active material, and a material having a shape easily rolled during electrode rolling as a conductive material is coated on an electrode current collector, and a lithium secondary battery including the same are provided.

First claim

The invention claimed is:

1. A positive electrode for a secondary battery, comprising:
an electrode layer having a positive electrode active material and a first conductive material; and
a positive electrode current collector,
wherein the first conductive material is one of natural graphite, artificial graphite thermally treated at 2800° C. or more, or a combination thereof, and present in an amount ranging from 0.1 wt % to 5 wt % based on a total weight of the electrode layer, and
wherein the first conductive material has an average particle diameter ranging from 3 micrometers to 20 micrometers,
wherein a specific surface area of the first conductive material is 5.0 m 2 /g to 8.0 m 2 /g,
wherein a tap density of the first conductive material is 0.8 g/ml to 1.2 g/ml,
wherein a true density of the first conductive material is 2.20 g/cc to 2.30 g/cc, and
wherein a spheroidization degree of the first conductive material is 10 to 100.

2. The positive electrode according to claim 1 , wherein the electrode active material comprises particles of positive electrode active material.

3. The positive electrode according to claim 1 , wherein the first conductive material is uniformly distributed in the electrode layer.

4. The positive electrode according to claim 1 , wherein the first conductive material is present on a surface of the electrode active material.

5. The positive electrode according to claim 1 , wherein the first conductive material has a scale shape, a spherical shape, an oval shape, a fiber shape, a spindle shape or an onion shape.

6. The positive electrode according to claim 1 , wherein the electrode active material comprises a lithium transition metal oxide represented by Formula 1 or 2 below:
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, Ti, Cu, B, Ca, Zn, Zr, Nb, Mo, Sr, Sb, W, Ti and Bi;
A is at least one monovalent or divalent anion; and
0.9≤ x≤ 1.2, 0< y< 2, and 0≤ z< 0.2,

(1− x )LiM′O 2-y A y −x Li 2 MnO 3-y′ 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.

7. The positive electrode according to claim 1 , wherein the electrode active material comprises first particles having average particle diameters (D50) of 10 nanometers to 50 nanometers and/or secondary particles, in which the first particles are agglomerated, having average particle diameters (D50) of 3 micrometers to 15 micrometers.

8. The positive electrode according to claim 1 , wherein a porosity of the electrode layer is 17% to 32%.

9. A secondary battery comprising the electrode according to claim 1 .

10. The secondary battery according to claim 9 , wherein the secondary battery is a lithium ion battery, a lithium ion polymer battery, or a lithium polymer battery.

11. A battery module comprising the secondary battery according to claim 9 as a unit cell.

12. A battery pack comprising the battery module according to claim 11 .

13. A device comprising the battery pack according to claim 12 as a power source.

14. The device according to claim 13 , wherein the device is an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a system for power storage.

15. The positive electrode according to claim 1 , wherein the first conductive material is present in an amount ranging from 0.5 wt % to 5 wt % based on a total weight of the electrode layer.

16. The positive electrode according to claim 1 , wherein the electrode layer further comprises a second conductive material different from the first conductive material.

17. The positive electrode according to claim 16 , wherein the second conductive material is selected from the group consisting of natural graphite that is not thermally treated, artificial graphite that is not thermally treated; carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, and mixtures thereof.

Assignees

• Lg Chemical Ltd

Inventors

• Uhm In Sung
• Kim Je Young
• Kwon Ji Yoon

Classifications

• H01M4/1391

  of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/131 Primary

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M4/625

  Carbon or graphite · CPC title

• H01M2004/028

  Positive electrodes · CPC title