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