Positive electrode material for lithium ion secondary batteries, and method for producing same

Patent metadata

Field	Value
Publication number	US-2016126549-A1
Application number	US-201414895650-A
Country	US
Kind code	A1
Filing date	Jun 5, 2014
Priority date	Jun 6, 2013
Publication date	May 5, 2016
Grant date	—

Abstract

The present invention relates to a lithium manganese composite oxide having a metal-containing compound film and a carbon coating, in which at least a part of a surface of the lithium manganese composite oxide represented by Formula (1) is coated with the metal-containing compound film, and at least a part of the surface thereof is further coated with the carbon coating. The present invention can provide a positive electrode material capable of improving the discharge characteristics and the capacity retention rate after cycles of lithium ion secondary batteries.
Li 1+x (Fe y Ni z Mn 1-y-z ) 1-x O 2   (1),
where 0<x<⅓, 0≦y, 0≦z<0.5, and y+z<1.

First claim

1 . A lithium manganese composite oxide having a metal-containing compound film and a carbon coating, wherein
at least a part of a surface of the lithium manganese composite oxide represented by Formula (1):
Li 1+x (Fe y Ni z Mn 1-y-z ) 1-x O 2   (1),

where 0<x<⅓, 0≦y, 0≦z<0.5, and y+z<1
is coated with the metal-containing compound film, and at least a part of the surface thereof is further coated with the carbon coating.

2 . The lithium manganese composite oxide having a metal-containing compound film and a carbon coating according to claim 1 , wherein
the metal-containing compound is one or more selected from the group consisting of oxides and phosphate compounds of a metal, and the metal is at least one selected from the group consisting of Ti, Al, Fe, Mg, K, Na, Zn, Ce, Ca, Zr, Ge and Sn.

3 . The lithium manganese composite oxide having a metal-containing compound film and a carbon coating according to claim 1 , wherein
the metal-containing compound film and the carbon coating each has a mass of not more than 20 mass % with respect to a mass of the lithium manganese composite oxide represented by Formula (1).

4 . The lithium manganese composite oxide having a metal-containing compound film and a carbon coating according to claim 1 , wherein the metal-containing compound film is formed by heat treatment of one or more metal compounds selected from the group consisting of metal inorganic salts, metalorganometallic compounds, metal complexes, and metal alkoxides, and a metal constituting the metal compound is at least one selected from the group consisting of Ti, Al, Fe, Mg, K, Na, Zn, Ce, Ca, Zr, Ge, and Sn.

5 . The lithium manganese composite oxide having a metal-containing compound film and a carbon coating according to claim 1 , wherein
the carbon coating is formed by heat treatment of at least one selected from the group consisting of porphyrin compounds, phthalocyanine compounds, and polycyclic aromatic hydrocarbons.

6 . The lithium manganese composite oxide having a metal-containing compound film and a carbon coating according to claim 1 , wherein
the carbon coating is formed by a chemical vapor deposition method.

7 . A lithium ion secondary battery comprising the lithium manganese composite oxide having a metal-containing compound film and a carbon coating according to claim 1 as an electrode active material.

8 . A method for producing a lithium manganese composite oxide having a metal-containing compound film and a carbon coating, comprising the steps of:
coating at least a part of a surface of the lithium manganese composite oxide represented by Formula (2):
Li 1+x (Fe y Ni z Mn 1-y-z ) 1-x O 2   (2):

where 0<x<⅓, 0≦y, 0≦z<0.5, and y+z<1
with the metal-containing compound, and
further coating, with the carbon coating, at least a part of the surface of the lithium manganese composite oxide coated with the metal-containing compound.

9 . The method for producing a lithium manganese composite oxide having a metal-containing compound film and a carbon coating according to claim 8 , wherein
the step of coating with the metal-containing compound comprises:
a first step of allowing at least one metal compound selected from the group consisting of metal inorganic salts, organometallic compounds, metal complexes, and metal alkoxides to be adsorbed by a liquid phase method onto the surface of the lithium manganese composite oxide represented by Formula (2): and
a second step of heat-treating to form the metal-containing compound film on at least a part of the surface of the lithium manganese composite oxide represented by Formula (2), and
the step of coating with the carbon coating comprises:
a third step of allowing at least one selected from the group consisting of porphyrin compounds, phthalocyanine compounds, and polycyclic aromatic hydrocarbons to be adsorbed by the liquid phase method onto the surface of the lithium manganese composite oxide having the metal-containing compound film obtained by the second step; and
a fourth step of heat-treating to form the carbon coating on at least a part of the surface of the lithium manganese composite oxide having the metal-containing compound film.

10 . The method for producing a lithium manganese composite oxide having a metal-containing compound film and a carbon coating according to claim 8 , wherein
the step of coating with the metal-containing compound comprises:
a first step of allowing at least one metal compound selected from the group consisting of metal inorganic salts, organometallic compounds, metal complexes, and metal alkoxides to be adsorbed by a liquid phase method onto the surface of the lithium manganese composite oxide represented by Formula (2): and
a second step of heat-treating to form the metal-containing compound film on at least a part of the surface of the lithium manganese composite oxide represented by Formula (2), and
the step of coating with the carbon coating comprises:
a third step of forming the carbon coating by a chemical vapor deposition method on at least a part of the surface of the lithium manganese composite oxide having the metal-containing compound film obtained by the second step

Assignees

• Nec Corp

Inventors

• Yuge Ryota
• Nakahara Kentaro
• Hattori Sadanori

Classifications

• C01P2004/62

  Submicrometer sized, i.e. from 0.1-1 micrometer · CPC title

• H01M4/525 Primary

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M10/0525

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

• C01G53/50

  of the type (MnO2)n-, e.g. Li(NixMn1-x)O2 or Li(MyNixMn1-x-y)O2 · CPC title

• H01M4/131

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