Positive electrode and secondary battery using same

Patent metadata

Field	Value
Publication number	US-10693123-B2
Application number	US-201515502123-A
Country	US
Kind code	B2
Filing date	Aug 6, 2015
Priority date	Aug 7, 2014
Publication date	Jun 23, 2020
Grant date	Jun 23, 2020

Abstract

The present invention relates to a positive electrode comprising a Mn composite oxide having a tetragonal structure represented by formula (1): Li a (M x Mn 2-x-y Y y )(O 4-w Z w )(wherein 1<a≤2.6, 0≤x≤1.2, 0≤y, x+y<2, 0≤w≤1; M is at least one selected from the group consisting of Co, Ni, Fe, Cr and Cu; Y is at least one selected from the group consisting of Li, B, Na, Mg, Al, Ti, Si, K and Ca; Z is at least one of F or Cl; and a composite oxide having a layered structure represented by formula (2): Li(Li x M 1-x-y Y y )O 2 (wherein 0≤x<0.3, 0≤y<0.3; M is at least one selected from the group consisting of Co, Fe, Ni and Mn; Y is at least one selected from the group consisting of Mg, Al, Zr, Ti and Zn. According to the present invention, a lithium secondary battery having a high capacity and being excellent in cycle life can be provided.

First claim

The invention claimed is:

1. A positive electrode comprising:
a Mn composite oxide having a tetragonal structure (active material (3)) represented by the following formula (3):
Li a Ni x Mn 2-x-y A y O 4   formula (3)

wherein in the formula (3), 1<a≤2.6, 0.4<x<0.6, 0<y<0.3, A is at least one selected from the group consisting of B, Na, Mg, Al, Ti and Si; and
a composite oxide having a layered structure (active material (2)) represented by
Li(Li x M 1-x-y Y y )O 2   formula (2)

wherein in the formula (2), 0≤x<0.3, 0≤y<0.3; M is at least one selected from the group consisting of Co, Fe, Ni and Mn; Y is at least one selected from the group consisting of Mg, Al, Zr, Ti and Zn.

2. The positive electrode according to claim 1 , wherein in the formula (3), a is 1.05≤a≤2.0.

3. The positive electrode according to claim 1 , wherein in the formula (3), x satisfies 0.5≤x<0.6.

4. The positive electrode according to claim 1 , wherein in the formula (2), x satisfies 0<x<0.3.

5. The positive electrode according to claim 1 , wherein the active material (2) is a composite oxide having a layered structure represented by the following formula (4):
Li(Li x M1 1-x-z Mn z )O 2   formula (4)

wherein in the formula (4), 0≤x<0.3, 0.3≤z≤0.7; M1 is at least one selected from the group consisting of Co, Ni and Fe.

6. The positive electrode according to claim 5 , wherein in the formula (4), x satisfies 0<x<0.3.

7. The positive electrode according to claim 1 , wherein the total content of the layered composite oxide represented by the formula (2) in the positive electrode active material is 2 to 70 wt %.

8. The positive electrode according to claim 1 , wherein the total content of the layered composite oxide represented by the formula (2) in the positive electrode active material is 5 to 50 wt %.

9. A lithium ion secondary battery, comprising the positive electrode according to claim 1 and a negative electrode.

10. The lithium ion secondary battery according to claim 9 , wherein the negative electrode comprises a metal that can be alloyed with lithium or a metal oxide that can absorb and desorb a lithium ion.

11. The lithium ion secondary battery according to claim 9 , wherein the negative electrode comprises Si oxide.

12. A vehicle equipped with the secondary battery according to claim 9 .

Assignees

• Nec Corp

Inventors

• Takahashi Makiko
• Noguchi Takehiro
• Katou Yuukou

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• Y02T10/70

  Energy storage systems for electromobility, e.g. batteries · CPC title

• Y02P70/50

  Manufacturing or production processes characterised by the final manufactured product · CPC title

• C01G53/54

  of the type (Mn2O4)-, e.g. Li(NixMn2-x)O4 or Li(MyNixMn2-x-y)O4 · CPC title

• H01M4/386

  Silicon or alloys based on silicon · CPC title