Electrode material, electrode and lithium ion battery
An electrode material contains an agglomerate formed by agglomerating a plurality of agglomerated particles formed by agglomerating a plurality of particles of a carbonaceous coated electrode active material having a carbonaceous coat formed on a surface, the agglomerate is made up of hollow-structured particles and solid-structured particles, the average particle diameter of the agglomerate is in a range of 0.5 μm to 100 μm, the volume density of the agglomerate is in a range of 50% by volume to 80% by volume, the micropore distribution of micropores present in the agglomerate is monomodal, the average micropore diameter in the micropore distribution is 0.3 μm or less, and the NMP oil absorption amount of the agglomerate is in a range of 40 g/100 g to 100 g/100 g.
1. An electrode material comprising:
an agglomerate formed by agglomerating a plurality of agglomerated particles formed by agglomerating a plurality of particles of a carbonaceous coated electrode active material having a carbonaceous coat formed on a surface,
wherein the agglomerate is made up of hollow-structured particles containing voids and solid-structured particles,
an average particle diameter of the agglomerate is in a range of 0.5 μm to 100 μm,
a volume density of the agglomerate is in a range of 50% by volume to 80% by volume of a theoretical density of the electrode active material,
a micropore distribution of micropores present in the agglomerate is monomodal, an average micropore diameter in the micropore distribution is 0.3 μm or less, and
an N-methyl-2-pyrollidone oil absorption amount of the agglomerate is in a range of 40 g/100 g to 100 g/100 g,
a diameter of the voids in the hollow-structured particles is in a range of 3.5 μm to 5.5 μm, and
a ratio of a number of the hollow-structured particles of the agglomerates to a number of both of the hollow-structured particles and the solid-structured particles of the agglomerates is in the range of 15/50 to 24/50.
2. The electrode material according to claim 1 ,
wherein a ratio of a film thickness of a carbonaceous coat in an inner circumferential portion to the film thickness of the carbonaceous coat in an outer circumferential portion of an outer shell of the agglomerate is in a range of 0.7 to 2.0.
3. An electrode comprising:
electrode material according to claim 1 .
4. A lithium ion battery comprising:
a positive electrode made of the electrode according to claim 3 .
5. The electrode material according to claim 1 , wherein
the plurality of particles of the carbonaceous coated electrode active material are strongly bonded together through the carbonaceous coats forming a neck-like shape with a small cross-sectional area, and
channel-like or net-like micropores spread three-dimensionally inside an outer shell of the agglomerate, and
the voids formed in the agglomerate and an outer space of the agglomerate are coupled through the channel-like or net-like micropores.
6. The electrode material according to claim 1 , wherein the electrode active material comprises one element selected from a group of Li x A y D z PO 4 as a principal component, wherein A represents one or more selected from a group consisting of Co, Mn, Ni, Fe, Cu and Cr; D represents one or two or more selected from a group consisting of Mg, Ca, S, Sr, Ba, Ti, Zn, B, Al, Ga, In, Si, Ge, Sc, Y and rare earth elements; and 0<x<2, 0<y<1.5, and 0<z<1.5.
7. The electrode material according to claim 1 , wherein 80% or more of the surfaces of the particles of a carbonaceous coated electrode active material are coated with the carbonaceous coat.
8. The electrode material according to claim 1 , wherein a micropore diameter (D90) at which a cumulative volume percentage from a small micropore diameter side becomes 90% is 1.0 μm or less.
9. The electrode material according to claim 1 , wherein a micropore diameter (D50) at which a cumulative volume percentage from a small micropore diameter side becomes 50%, is preferably 0.3 μm or less.
10. The electrode material according to claim 1 , an internal resistance of the electrode material is 20Ω or less.
11. The electrode material according to claim 1 , wherein an average particle diameter of primary particles size of the electrode active material is in a range of 0.01 μm to 20 μm.
12. The electrode material according to claim 1 , wherein the electrode active material comprises at least one kind of particles selected from the group consisting of spherical particles, rectangular particles and rod-like particles.
13. The electrode material according to claim 1 , wherein the electrode materials is obtained by a manufacturing method which comprises steps of
producing a slurry by mixing an electrode active material or a precursor thereof, an organic compound and a solvent,
spraying and drying the slurry to obtain a dried substance, and
firing the dried substance at a temperature in a range of 500° C. to 1000° C. in a non-oxidizing atmosphere.
14. The electrode material according to claim 13 , wherein the organic compound comprise any one or more compound selected from the group consisting of polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl acetate, cellulose, carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose and hydroxylethyl cellulose, glucose, fructose, galactose, mannose, maltose, sucrose and lactose, starch, gelatin, polyacrylic acid, polystyrene sulfonate, polyacrylamide, glycogen, pectin, alginic acid, glucomannan, chitin, hyaluronic acid, chondroitin, agarose, polyethers and ethylene glycol,and glycerin.
15. The electrode material according to claim 13 , wherein a mixing ratio of the organic compound to the electrode active material is in a range of 0.6 parts by mass to 10 parts by mass.