Cathode material and lithium ion battery

1. A cathode material comprising an aggregate formed by aggregating active material particles,

wherein the active material particle is a particle including a cathode active material as a formation material, and a carbonaceous material is provided on a surface of the particle,

the amount of the carbonaceous material is in a range of 0.6 to 2.08% by mass with respect to 100 parts by mass of the cathode active material,

a ratio between a mass ratio (% by mass) of carbon contained in the aggregate to a BET specific surface area (m 2 /g) of the cathode material is in a range of 0.08 to 0.2,

a tap density is in a range of 0.9 g/m 3 to 1.5 g/cm 3 ,

an oil absorption amount for which N-methyl-2-pyrrolidone is used is 70 cc/100 g or less,

the active material particle includes

a central particle formed of the cathode active material and a coating layer which is formed on a surface of the central particles and is formed of the carbonaceous material,

wherein the central particle includes

a first layer including Li x A y D z PO 4 wherein A represents two or more metal elements selected from a group consisting of Co, Mn, Ni, Fe, Cu, and Cr, D represents one or more elements selected from a group consisting of Mg, Ca, Sr, Ba, Ti, Zn, B, Al, Ga, In, Si, Ge, Sc, Y and rare earth elements, 0.8<x<1.5, 0<y≤1 and 0≤z<1.5), and

a second layer which coats the first layer and includes LiFePO 4 as carbonization catalyst.

2. A lithium ion battery comprising the cathode material according to claim 1 .

3. The cathode material according to claim 1 wherein the central particle is formed of LiFe 0.2 Mn 0.8 PO 4 .

4. The cathode material according to claim 1 , wherein the oil absorption amount for which N-methyl-2-pyrrolidone is used is 48.3 to 70 cc/100 g.