CARBON MATERIAL FOR LITHIUM ION SECONDARY BATTERY, NEGATIVE ELECTRODE MATERIAL FOR LITHIUM ION SECONDARY BATTERY, AND LITHIUM ION SECONDARY BATTERY

摘要

Disclosed is a carbon material for lithium ion secondary cell having a positron lifetime of 370 picoseconds or longer, and 480 picoseconds or shorter, when measured by positron annihilation spectroscopy under conditions (A) to (E) below:
(A) positron radiation source: positrons generated from electron-positron pairs using an electron accelerator;
(B) gamma ray detector: a BaF 2 scintillator and a photoelectron multiplier;
(C) measurement temperature and atmosphere: 25°C, in vacuum;
(D) annihilation ³-ray counts: 3×10 6 or larger; and
(E) positron beam energy: 10 keV.