LITHIUM ION SECONDARY BATTERY

摘要

A lithium ion secondary battery comprising a positive electrode, a non-aqueous electrolyte, a separator and a negative electrode comprising a carbon material capable of charging and discharging lithium ions, said negative electrode containing at least one type of graphite material which satisfies the following conditions (a) and (b): (a) a graphite material falling within a defined region in the relation between its particle size and specific surface area; (b) in Raman spectroscopic analysis, the ratio of the strength of the peak existing in the region of 1,350-1,370 cm<-1) (IA), which is represented by an R value (IB/IA), is 0.001 to 0.2. This battery has high capacity and is also excellent in rapid charge/discharge characteristics, flatness of charge/discharge potential and cycle performance.