Positive electrode material for lithium ion secondary battery, positive electrode for lithium ion secondary battery, and lithium ion secondary battery

1. A positive electrode material for a lithium ion secondary battery comprising:

an olivine-type phosphate-based compound represented by General Formula LixAyDzPO 4 ; and

carbon,

wherein, in transmission electron microscopic observation of a cross section of a secondary particle that is an agglomerate of primary particles of the olivine-type phosphate-based compound, a 300-point average value of filling rates of the carbon that fills insides of voids having a diameter of 5 nm or larger that are formed by the primary particles is 30 to 70%,

wherein a value (c/a) obtained by dividing the amount of carbon (c) by a specific surface area (a) is 0.07 to 0.14,

wherein a tap density is 1.0 to 1.6 g/cm 3 , and

wherein, in the general formula, A represents at least one element selected from the group consisting of Co, Mn, Ni, Fe, Cu, and Cr, D represents at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Ti, Zn, B, Al, Ga, In, Si, Ge, Sc, and Y, and x, y, and z satisfy 0.9<x<1.1, 0<y≤1.0, 0≤z<1.0, and 0.9<y+z<1.1.

2. The positive electrode material for a lithium ion secondary battery according to claim 1 ,

wherein the amount of carbon (c) is 0.7% to 3.0% by mass, and

the specific surface area (a) is 5 to 35 m 2 /g.

3. A positive electrode for a lithium ion secondary battery, comprising:

an electrode current collector; and

a positive electrode mixture layer formed on the electrode current collector,

wherein the positive electrode mixture layer contains the positive electrode material for a lithium ion secondary battery according to claim 1 .

4. A lithium ion secondary battery comprising:

a positive electrode;

a negative electrode; and

an electrolyte,

wherein the positive electrode for a lithium ion secondary battery according to claim 3 is provided as the positive electrode.