Positive electrode active material with high capacity and lithium secondary battery including the same

Patent metadata

Field	Value
Publication number	US-9324994-B2
Application number	US-201113167460-A
Country	US
Kind code	B2
Filing date	Jun 23, 2011
Priority date	Feb 24, 2010
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

A high capacity lithium secondary battery includes a lithium manganese oxide having a layered structure exhibiting a great irreversible capacity in the event of overcharging at a high voltage and a spinel-based lithium manganese oxide. Because it is activated at a high voltage of 4.45 V or higher based on a positive electrode potential, additional lithium for utilizing a 3V range of the spinel-based lithium manganese oxide can be provided and an even profile in the entire SOC area can be obtained. Because the lithium secondary battery includes the mixed positive electrode active material including the spinel-based lithium manganese oxide and the lithium manganese oxide having a layered structure, and is charged at a high voltage, its stability can be improved. Also, the high capacity battery having a large available SOC area and improved stability without causing an output shortage due to a rapid voltage drop in the SOC area can be implemented.

First claim

What is claimed is:

1. A lithium secondary battery, comprising a positive electrode mix comprising a conductive material, binder and mixed positive electrode active material,
wherein the mixed positive electrode active material comprises:
a complex of a spinel-based lithium manganese oxide represented by [Chemical Formula 1] shown below with a carbon-based material in the range of 1 wt % to 15 wt % as a total weight of the complex, wherein in the complex, the carbon-based material is coated on the surface of particles of the spinel-based lithium manganese oxide, and
a lithium manganese oxide having a layered structure represented by [Chemical Formula 2] shown below:
wherein the mixed positive electrode active material includes 10 wt % to 40 wt % of the complex and 60 wt % to 90 wt % of the lithium manganese oxide having a layered structure represented by [Chemical Formula 2] over 100 wt % as a total weight of the mixed positive electrode active material; and
wherein the carbon-based material is one or more selected from the group consisting of graphene and conductive polymer,
wherein the mixed positive electrode active material further comprises any one or two or more lithium-containing metal oxides selected from the group consisting of a lithium cobalt oxide, a lithium nickel oxide, a lithium manganese oxide, a lithium cobalt-nickel oxide, a lithium cobalt-manganese oxide, a lithium manganese-nickel oxide, a lithium cobalt-nickel-manganese oxide, and an oxide formed by substituting these with other elements or formed by doping other element(s) therein;
Li 1+y Mn 2−y−z M z O 4−x Q x   [Chemical Formula 1]

wherein 0≦x≦1, 0≦y≦0.3, and 0≦z≦1, and M is one or more selected from the group consisting of Mg, Al, Ni, Co, Fe, Cr, Cu, B, Ca, Nb, Mo, Sr, Sb, W, B, Ti, V, Zr, and Zn, and Q is one or more selected from the group consisting of N, S, and Cl, and
a Li 2 MnO 3 -(1- a )LiMO 2   [Chemical Formula 2]

wherein 0<a<1 and M is any one selected from the group consisting of Al, Mg, Mn, Ni, Co, Cr, V, Fe, Cu, Zn, Ti, and B, or two or more them simultaneously applied.

2. The lithium secondary battery of claim 1 , wherein the other element(s) may be any one or two or more elements selected from the group consisting of Al, Mg, Mn, Ni, Co, Cr, V, and Fe.

3. The lithium secondary battery of claim 1 , wherein the lithium-containing metal oxide is included to be 50 wt % or less over the total weight of the mixed positive electrode active material.

4. The lithium secondary battery of claim 1 , wherein the lithium secondary battery is used as a unit cell of a battery module as a power source of a midsize or large device.

5. The lithium secondary battery of claim 4 , wherein the midsize or large device is a power tool; an electric vehicle including an electric vehicle (EV), a hybrid electric vehicle (HEV), and a plug-in hybrid electric vehicle (PHEV); an electric two-wheeled vehicle including an E-bike and an E-scooter; an electric golf cart; an electric truck; or an electric commercial vehicle or a power storage system.

6. A method for manufacturing a lithium secondary battery, the method comprising:
fabricating a mixed positive electrode active material by mixing a complex of a spinel-based lithium manganese oxide represented by [Chemical Formula 1] shown below with a carbon-based material or a precursor of the carbon-based material and a lithium manganese oxide having a layered structure represented by [Chemical Formula 2] shown below,
mixing the mixed positive electrode active material with a conductive material and binder to prepare a positive electrode mix;
fabricating a lithium secondary battery including the positive electrode mix;
charging the lithium secondary battery at a voltage of 4.45 V or higher based on a positive electrode potential; and
performing degassing,
wherein the mixed positive electrode active material includes 10 wt % to 40 wt % of the complex and 60 wt % to 90 wt % of the lithium manganese oxide having a layered structure represented by [Chemical Formula 2] over 100 wt % as a total weight of the mixed positive electrode active material,
wherein the mixed positive electrode active material further comprises any one or two or more lithium-containing metal oxides selected from the group consisting of a lithium cobalt oxide, a lithium nickel oxide, a lithium manganese oxide, a lithium cobalt-nickel oxide, a lithium cobalt-manganese oxide, a lithium manganese-nickel oxide, a lithium cobalt-nickel-manganese oxide, and an oxide formed by substituting these with other elements or formed by doping other element(s) therein,
wherein the carbon-based material is one or more selected from the group consisting of graphene and conductive polymer,
wherein in the complex, the carbon-based material is coated on the surface of particles of the spinel-based lithium manganese oxide represented by [Chemical Formula 1];
Li 1+y Mn 2−y−z M z O 4−x Q x   [Chemical Formula 1]

wherein 0≦x≦1, 0≦y≦0.3, and 0≦z≦1, and M is one or more selected from the group consisting of Mg, Al, Ni, Co, Fe, Cr, Cu, B, Ca, Nb, Mo, Sr, Sb, W, B, Ti, V, Zr, and Zn, and Q is one or more selected from the group consisting of N, S, and Cl, and
a Li 2 MnO 3 -(1- a )LiMO 2   [Chemical Formula 2]

wherein 0<a<1 and M is any one selected from the group consisting of Al, Mg, Mn, Ni, Co, Cr, V, Fe, Cu, Zn, Ti, and B, of two or more them simultaneously applied.

7. The method of claim 6 , wherein, in charging the lithium secondary battery, the lithium secondary battery is charged at a voltage of 4.45V or higher based on the positive electrode potential in a formation operation, or in every several cycles or in every cycle following the formation operation.

8. The method of claim 6 , wherein the complex is fabricated according to a dry method through high energy milling.

9. The method of claim 6 , wherein the complex is fabricated according to a wet method of dispersing the carbon-based material and the spinel-based lithium manganese oxide represented by [Chemical Formula 1] in a solvent, coating the surface of the precursor of the carbon-based material, drying the same, and retrieving the solvent.

10. The method of claim 6 , wherein the complex is fabricated by mixing a lithium precursor and a manganese precursor, synthetic raw materials of the spinel-based lithium manganese oxide represented by [Chemical Formula 1], and the carbon-based material or the precursor of the carbon-based material and firing the mixture at a temperature range of 650° C. to 800° C. in which the carbon-based material or the precursor is not oxidized.

Assignees

• Oh Song Taek
• Kim Sun Kyu
• Chung Geun Chang
• Kim Sin Kyu
• Lee Hyun Seok
• Youn Bong Kook
• Lg Chemical Ltd

Inventors

• Oh Song Taek
• Kim Sun Kyu
• Chung Geun Chang
• Kim Sin Kyu
• Lee Hyun Seok
• Youn Bong Kook

Classifications

• Y02P70/54

  Cross-Sectional Technologies · mapped topic

• H01M4/505 Primary

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M10/0525

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

• H01M4/364

  as mixtures · CPC title

• H01M4/0447

  of complete cells or cells stacks · CPC title