Electrode material and method for producing the same

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.

1 . An 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, and   a volume density of the aggregate is 50 to 80 vol % of the volume density in a case in which the aggregate is a solid.   
     
     
         2 . The electrode material according to  claim 1 ,
 wherein 80% or more of the surface of the electrode-active material is covered with the carbonaceous film.   
     
     
         3 . The electrode material according to  claim 1 ,
 wherein the aggregate is 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.   
     
     
         4 . The electrode material according to  claim 1 ,
 wherein an amount of carbon in the carbonaceous film is 0.6 to 10 parts by mass on the basis of 100 parts by mass of the electrode-active material.   
     
     
         5 . The electrode material according to  claim 1 , wherein a tap density of the aggregate is 1.0 to 1.5 g/cm 3 . 
     
     
         6 . The electrode material according to  claim 1 ,
 wherein the electrode-active material contains one kind selected from the group consisting of lithium cobaltate, lithium nickelate, lithium manganate, lithium titanate, and Li x A y D z PO 4  (provided that, A is one or more kinds selected from the group consisting from Co, Mn, Ni, Fe, Cu, and Cr, D is one or more kinds 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) as a main component.   
     
     
         7 . A method for producing an electrode material, comprising:
 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 D90 to D10 of a particle size distribution of the electrode-active material or the precursor of the electrode-active material 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.   
     
     
         8 . An 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, 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.   
     
     
         9 . The electrode material according to  claim 8 ,
 wherein 80% or more of the surface of the electrode-active material is covered with the carbonaceous film.   
     
     
         10 . The electrode material according to  claim 8 ,
 wherein the aggregate is 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.   
     
     
         11 . The electrode material according to  claim 8 ,
 wherein an amount of carbon in the carbonaceous film is 0.6 to 10 parts by mass on the basis of 100 parts by mass of the electrode-active material.   
     
     
         12 . The electrode material according to  claim 8 ,
 wherein a tap density of the aggregate is 1.0 to 1.5 g/cm 3 .   
     
     
         13 . The electrode material according to  claim 8 ,
 wherein the electrode-active material contains one kind selected from the group consisting of lithium cobaltate, lithium nickelate, lithium manganate, lithium titanate, and Li x A y D z PO 4  (provided that, A is one or more kinds selected from the group consisting from Co, Mn, Ni, Fe, Cu, and Cr, D is one or more kinds 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) as a main component.   
     
     
         14 . A method for producing an electrode material, comprising:
 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.