Composite graphite particle for nonaqueous secondary battery, negative electrode material containing the same, negative electrode and nonaqueous secondary battery

摘要

To provide a nonaqueous secondary battery exhibiting a sufficiently small charge/discharge irreversible capacity in the initial cycle, exhibiting an excellent charge acceptance and excellent cycle characteristics, even when the negative electrode material-containing active material layer on a current collector is highly densified so as to obtain a high capacity. A composite graphite particle for nonaqueous secondary batteries, which is a composite graphite particle (B) obtained by forming a spherical graphite particle (A) and a graphitized product of graphitizable binder, wherein the spherical graphite particle (A) is a specific graphite particle or the composite graphite particle satisfies (a) and/or (b):
(a) assuming that the cumulative 50% diameter (d50 size), 90% diameter (d90 size) and 10% diameter (d10 size) of the (A) by a laser diffraction method are D50(A), D90(A) and D10(A), respectively, and the cumulative 50% diameter (d50 size), 90% diameter (d90 size) and 10% diameter (d10 size) of the (B) by a laser diffraction method are D50(B), D90(B) and D10(B), respectively, the composite graphite particle satisfies all of (formula 1), (formula 2) and (formula 3):
1.1≦D50(B)/D50(A)≦2.0  (formula 1)1.1≦D90(B)/D90(A)≦2.4  (formula 2)1.0≦D10(B)/D10(A)≦1.8  (formula 3)(b) assuming that the value of 110(A)/004(A) which is the ratio between 110 plane and 004 plane measured from XRD of the (A) is x and the value of 110(B)/004(B) which is the ratio between 110 plane and 004 plane measured from XRD of the (B) is y, the ratio z therebetween is defined by the following formula and z is from 1.2 to 3.5:
z=y/x.

主权项

1. A composite graphite particle (B), obtained by forming a composite comprising:
a spherical graphite particle (A); and a graphitized product of graphitizable binder, wherein said composite graphite particle (B) satisfies at least one of (a) and (b): (a) a cumulative 50% diameter (d50 size), 90% diameter (d90 size) and 10% diameter (d10 size) of the spherical graphite particle (A) laser diffraction are represented by D50(A), D90(A) and D10(A), respectively, and the cumulative 50% diameter (d50 size), 90% diameter (d90 size) and 10% diameter (d10 size) of the composite graphite particle (B) by laser diffraction are represented by D50(B), D90(B) and D10(B), respectively, and the composite graphite particle satisfies all of (formula 1), (formula 2) and (formula 3):
1.1≦D50(B)/D50(A)≦2.0  (formula 1),1.1≦D90(B)/D90(A)≦2.4  (formula 2),1.0≦D10(B)/D10(A)≦1.8  (formula 3); and (b) a value of 110(A)/004(A) which is the ratio between 110 plane and 004 plane measured from XRD of the spherical graphite particle (A) is represented by x, and a value of 110(B)/004(B) which is the ratio between 110 plane and 004 plane measured from XRD of the composite graphite particle (B) is represented by y, and a ratio y/x is from 1.2 to 3.5.