Nonaqueous secondary battery

Details Nonaqueous secondary battery Nonaqueous secondary battery

2000-03-23

2003-04-22

Kalafut, Stephen (Department: 1745)

Chemistry: electrical current producing apparatus, product, and

Current producing cell, elements, subcombinations and...

Electrode

C429S224000, C429S231100, C429S231200, C429S231300, C429S231500

Reexamination Certificate

active

06551743

ABSTRACT:

BACKGROUND OF THE INVENTION
This application claims the Paris convention priority of Japanese Patent Application No. 11-078997/1999 filed on Mar. 24, 1999, which is incorporated herein by reference.
The present invention relates to a nonaqueous secondary battery requiring charge before initial discharge, and more particularly, it relates to improvement of a positive electrode active material for the purpose of improving the charge-discharge cycle performance of such a nonaqueous secondary battery.
Known positive electrode active materials for a nonaqueous secondary battery are lithium cobaltate (LiCoO
2
), lithium nickelate (LiNiO
2
), a lithium-cobalt-nickel composite oxide (LiCo
1−x
Ni
x
O
2
, wherein 0<x<1), and a composite oxide obtained by substituting another element for a part of cobalt or nickel of such a compound. When any of these positive electrode active materials is used together with a negative electrode material such as metallic lithium, lithium alloy and a carbon material, a nonaqueous secondary battery having a high voltage and a high energy density can be obtained.
The materials for these positive electrode active materials are, however, rare resources and expensive, which disadvantageously increases the fabrication cost for the battery.
Recently, a lithium-manganese composite oxide, such as a spinel lithium-manganese composite oxide (LiMn
2
O
4
) and an orthorhombic lithium-manganese composite oxide (LiMnO
2
), has attracted attention as an inexpensive positive electrode active material for a nonaqueous secondary battery, which is made from manganese, that is, an abundant resource, instead of expensive cobalt and nickel.
A lithium-manganese composite oxide, however, is degraded during repeated charge and discharge cycles due to elution of manganese, resulting in decreasing the discharge capacity in a small number of cycles. Therefore, even when the lithium-manganese composite oxide itself is used as a positive electrode active material, the resultant nonaqueous secondary battery cannot attain good charge-discharge cycle performance.
Accordingly, an object of the invention is providing a nonaqueous secondary battery that can be fabricated at lower cost than a nonaqueous secondary battery using an expensive material such as lithium cobaltate as a positive electrode active material and can attain better charge-discharge cycle performance than a nonaqueous secondary battery using a lithium-manganese composite oxide as a positive electrode active material. This object is achieved by using a specific composite oxide as a positive electrode active material as described in detail below.
SUMMARY OF THE INVENTION
The nonaqueous secondary battery of this invention (present battery) requiring charge before initial discharge comprises a positive electrode, a negative electrode and a nonaqueous electrolyte, and the positive electrode includes, as an active material, a composite oxide represented by a composition formula, Li
x
Mn
2−y−z
Ni
y
M
z
O
q
, wherein M is at least one element selected from the group consisting of B, Mg, Al, Ti, V, Fe, Co, Cu, Zn, Ga, Y, Zr, Nb, Mo and In; 1.20≦x≦1.80; y≧0.10; z≧0; y+z≦1.90; and 3.70≦q≦4.30, in a discharge state during fabrication of the battery.
By using this composite oxide as the positive electrode active material, the nonaqueous secondary battery of this invention can attain good charge-discharge cycle performance and can be fabricated at low cost.


REFERENCES:
patent: 5514496 (1996-05-01), Mishima et al.
patent: 5561006 (1996-10-01), Lecerf et al.
patent: 5620812 (1997-04-01), Tahara et al.
patent: 5718989 (1998-02-01), Aoki et al.
patent: 5795558 (1998-08-01), Aoki et al.
patent: 5882218 (1999-03-01), Reimers
patent: 5948565 (1999-09-01), Kelder
patent: 6193946 (2001-02-01), Kawano et al.
patent: 6274278 (2001-08-01), Pistoia et al.
patent: 6-295726 (1994-10-01), None
patent: 9-270259 (1997-10-01), None
patent: 11-016571 (1999-01-01), None
patent: 11-073966 (1999-03-01), None

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