Lithium secondary battery having improved output characteristics

Patent metadata

Field	Value
Publication number	US-10411249-B2
Application number	US-201615542994-A
Country	US
Kind code	B2
Filing date	Jan 21, 2016
Priority date	Jan 21, 2015
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

The present disclosure relates to a lithium secondary battery using lithium titanium oxide (LTO) as a negative electrode active material. More specifically, the present disclosure relates to a secondary battery having improved input and output characteristics through the optimization of the pore ratio of the LTO. The lithium secondary battery including the lithium titanium oxide negative electrode active material according to the present disclosure provides an effect of significantly improved output density through the maximization of reaction active sites with electrolyte due to a porous structure.

First claim

What is claimed is:

1. A negative electrode for a lithium secondary battery comprising:
a current collector, and a negative electrode active material layer formed on at least one side surface of the current collector,
wherein the negative electrode active material layer comprises lithium titanium oxide expressed with chemical formula 1 as follows as a negative electrode active material,
the negative electrode active material comprises secondary particles in which primary particles of lithium titanium oxide (LTO) are agglomerated,
the negative electrode active material layer is present with a plurality of pores, and
a volume of a meso pore having a long diameter of the pores of 0.1 μm or greater accounts for 10 vol % to 50 vol % in 100 vol % of entire pores present in the negative electrode active material layer
Li x Ti y O z M w   [Chemical formula 1]

where, M is one or a mixture of two or more selected from a group consisting of Zr, B, Sn, S, Be, Ge and Zn, 0.5≤x≤3, 1≤y≤5, 2≤z≤12, 0≤w<0.1.

2. The negative electrode of claim 1 , wherein the meso pore comprises a primary pore and/or a secondary pore, wherein the primary pore is a pore formed on a surface and in a body of the primary particle, and the secondary pore is a pore formed between the adjacent primary particle and/or secondary particle.

3. The negative electrode of claim 2 , wherein the negative electrode active material layer comprises 50 vol % or more of the secondary pore compared to 100 vol % of the meso pore.

4. The negative electrode of claim 1 , wherein the negative electrode active material layer has a porosity of 40% to 60%.

5. The negative electrode of claim 1 , wherein lithium titanium oxide expressed with the chemical formula 1 is one or more selected from a group consisting of Li 0.8 Ti 2.2 O 4 , Li 2.67 Ti 1.33 O 4 , Li 1.33 Ti 1.67 O 4 , Li 1.14 Ti 1.71 O 4 , Li 4 Ti 5 O 12 , and Li 2 TiO 3 .

6. The negative electrode of claim 1 , wherein the lithium titanium oxide primary particle has a diameter D 50 of 0.01 μm to 1 μm.

7. The negative electrode of claim 1 , wherein the lithium titanium oxide secondary particle has a diameter D 50 of 2 μm to 20 μm.

8. The negative electrode of claim 1 , wherein the lithium titanium oxide primary particle is a porous particle having a plurality of pores formed on a surface and in a body of the particle.

9. The negative electrode of claim 1 , wherein the lithium titanium oxide secondary particle is a porous particle having a plurality of pores formed on a surface and in a body of the particle.

10. The negative electrode of claim 1 , wherein a pore of the negative electrode active material layer comprises a pore formed on a surface and in a body of the primary particle, a pore formed between the primary particles, a pore formed between the primary particle and the secondary particle, and a pore formed between the secondary particles.

11. The negative electrode of claim 1 , wherein the negative electrode active material has lithium carbonate in an amount of 2 wt % or less compared to 100 wt % of total lithium titanium oxide.

12. The negative electrode of claim 1 , wherein the lithium titanium oxide has an x-ray diffraction measurement average crystallite size of 800 Å to 1300 Å.

13. A lithium secondary battery comprising the negative electrode according to claim 1 .

Assignees

• Lg Chemical Ltd

Inventors

• Lim Soo-Hyun
• Kim Dae-Hong
• Jeong Won-Hee
• Park Tae-Jin

Classifications

• H01M4/405

  Alloys based on lithium · CPC title

• H01M4/485

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title

• H01M2004/021

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

• H01M10/052

  Li-accumulators · CPC title

• H01M2004/027

  Negative electrodes · CPC title