Electrode material and method for producing the same

Patent metadata

Field	Value
Publication number	US-9698425-B2
Application number	US-201414567384-A
Country	US
Kind code	B2
Filing date	Dec 11, 2014
Priority date	Dec 17, 2010
Publication date	Jul 4, 2017
Grant date	Jul 4, 2017

Abstract

The present invention provides an electrode material in which unevenness in a supporting amount of a carbonaceous film is less when using an electrode-active material having a carbonaceous film on a surface thereof as the electrode material, and which is capable of improving conductivity, and a method for producing the electrode material. The electrode material includes an aggregate formed by aggregating an electrode-active material in which a carbonaceous film is formed on a surface. In the electrode material, an average particle size of the aggregate is 0.5 to 100 μm, a volume density of the aggregate is 50 to 80 vol % of a volume density in a case in which the aggregate is a solid, and 80% or more of the surface of the electrode-active material is covered with the carbonaceous film. Alternatively, the electrode material includes an aggregate formed by aggregating electrode-active material particles in which a carbonaceous film is formed on a surface. In the electrode material, an average particle size of the aggregate is 0.5 to 100 μm, a pore size (D50) when an accumulated volume percentage of a pore size distribution of the aggregate is 50% is 0.1 to 0.2 μm, and porosity of the aggregate is 15 to 50 vol % with respect to a volume in a case in which the aggregate is a solid.

First claim

We Claim:

1. A positive electrode material, comprising:
an aggregate formed by aggregating electrode-active material particles having a carbonaceous film formed on a surface,
wherein an average particle size of the aggregate is 0.5 to 100 μm,
a pore size (D50) when an accumulated volume percentage of a pore size distribution of the aggregate is 50% is 0.1 to 0.2 μm,
porosity of the aggregate is 15 to 50 vol % with respect to a volume of an aggregate in which a void is not present,
the aggregate has a plurality of voids at the inside, including a shell-like aggregate having a void at the inside, and a ratio of an average film thickness of the carbonaceous film in an outer peripheral portion and an inner peripheral portion of an outer shell of the shell-like aggregate (a thickness of the carbonaceous film in the inner peripheral portion/a thickness of the carbonaceous film in the outer peripheral portion) is 0.7 to 1.3,
a tap density of the aggregate is 1.0 to 1.5 g/cm 3 ,
the electrode-active material comprises Li x A y D z PO 4 as a main component, wherein A is one or more selected from the group consisting of Co, Mn, Ni, Fe, Cu, and Cr; D is one or more selected from the group consisting of Mg, Ca, S, Sr, Ba, Ti, Zn, B, Al, Ga, In, Si, Ge, Sc, Y, and rare-earth elements; 0<x<2; 0<y<1.5; and 0<z<1.5,
an amount of carbon in the carbonaceous film is 0.8 to 2.5 parts by mass on the basis of 100 parts by mass of the electrode-active material,
80% or more of the surface of the electrode-active material is covered with the carbonaceous film, and
an average particle size of primary particles of the electrode-active material particles is 0.02 to 5 μm.

2. The positive electrode material according to claim 1 , wherein the aggregate has a structure in which the electrode-active materials having the carbonaceous film formed on a surface thereof are aggregated in a point contact state, and thus a contact portion of the electrode-active materials forms a neck shape, whereby channel-shaped voids inside the aggregate have a three-dimensionally expanded structure.

3. The positive electrode material according to claim 1 , wherein the aggregate is a shell-like aggregate and the size of the void that is formed inside the aggregate is 80% or less of a diameter of aggregate particles.

4. The positive electrode material according to claim 1 , wherein the electrode active material has a spherical shape.

5. A method for producing a positive electrode material according to claim 1 , comprising:
spraying and drying slurry which contains an electrode-active material or a precursor of the electrode-active material, and an organic compound, and in which a ratio (D90/D10) of a particle size (D90) when an accumulated volume percentage of a particle size distribution of the electrode-active material or the precursor of the electrode-active material is 90% to a particle size (D10) when the accumulated volume percentage is 10% is 5 to 30; and
baking the resultant dried product that is obtained at 500° C. to 1,000° C. in a non-oxidizing atmosphere to obtain the electrode material;
wherein the electrode-active material comprises Li x A y D z PO 4 as a main component, wherein A is one or more selected from the group consisting of Co, Mn, Ni, Fe, Cu, and Cr; D is one or more selected from the group consisting of Mg, Ca, S, Sr, Ba, Ti, Zn, B, Al, Ga, In, Si, Ge, Sc, Y, and rare-earth elements; 0<x<2; 0<y<1.5; and 0<z<1.5.

6. The method for producing a positive electrode material according to claim 5 , wherein the ratio (D90/D10) of D90 to D10 of a particle size distribution of the electrode-active material or the precursor of the electrode-active material is 7 to 25.

Assignees

• Sumitomo Osaka Cement Co Ltd

Inventors

• Kitagawa Takao
• Yasumiishi Hirofumi
• Uehara Masaru

Classifications

• H01M4/366

  as layered products · CPC title

• H01M4/131

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

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M4/625 Primary

  Carbon or graphite · CPC title

• C01B31/02

  Chemistry & Metallurgy · mapped topic