Patent ID: 7947394
Filing Date: 2011-05-24
Classification: C01B,H01M,Y02E,Y02T

Abstract:
1. A nonaqueous electrolyte secondary battery negative electrode material, characterized by comprising: graphite particles, each having a structure where a plurality of flat graphite fine particulate assembles or bonds non-parallel with each other, each of the graphite particles having an aspect ratio of 5 or less and a volume of fine pores in the range of 10 to 10 a layer of carbon formed on the surface of each of the graphite particles, wherein a ratio (by weight ratio) of the layer of carbon to a respective graphite particle is in the range of 0.003 to 0.01, and wherein an average particle diameter (50% D) is 10 μm or more and 50 μm or less, the true specific gravity is 2.22 or more, the bulk density is 780 kg/m 3 or more and 1000 kg/m 3 or less, the specific surface area measured by a BET method is 2.0 m 2 /g or more and 5.0 m 2 /g or less, and, in a Raman spectrum analysis with argon laser light of a wavelength of 5145 Å, an R value expressed by R=I1350/I1580 (in Raman spectrum, I1580 denotes an intensity of a peak P1 in the range of 1580 to 1620 cm −1 and I1350 denotes an intensity of a peak P2 in the range of 1350 to 1370 cm4) is less than 0.2.