Patent ID: 6403259
Filing Date: 2002-06-11
Classification: H01M,Y02E,Y10T

Abstract:
A nonaqueous electrolyte secondary cell comprising a positive electrode, a negative electrode, and a separator interposed therebetween, said negative electrode comprising a negative electrode material that allows lithium ions to reversibly undergo repeated intercalation and deintercalation with each charge and discharge of said nonaqueous electrolyte secondary cell, and wherein said negative electrode material comprises a carbonaceous powder, said carbonaceous powder comprising particles that have a plural-layer structure with a surface layer of carbonaceous matter formed thereon, wherein said carbonaceous matter comprises from 0.1 to 50 wt % of said carbonaceous powder, and said particles have a mean particle size of from 11 to 40 microns, a mean thickness of the thinnest portion of at least 4 microns, provided that the mean thickness of the thinnest portion does not exceed the mean particle size, a specific surface area ranging from 1.0 to 5.0 m2/g, determined by a BET method, wherein said carbonaceous powder has a tapping density ranging from 0.7 g/cc to 1.2 g/cc, and a peak intensity ratio by Raman spectroscopy ranging from 0.01 to 1.0.