CARBON MATERIAL FOR LITHIUM ION SECONDARY BATTERIES

摘要

To provide a negative electrode material capable of giving a lithium ion secondary battery that is sufficiently small in the charge/discharge irreversible capacity observed at the initial cycle stage, has excellent high-temperature storage characteristics, and reduced in the gas generation at the initial cycle stage as well as during high-temperature storage. A carbon material for lithium ion secondary battery, wherein the surface functional group amount O/C value represented by the following formula 1 is from 1 to 4% and the sum (Cl/C+S 165 /C) of the surface functional group amount Cl/C value represented by the following formula 2 and the surface functional group amount S 165 /C value represented by the following formula 3 is from 0.05 to 0.5%: O / C value % = O atom concentration determined based on the peak area of the spectrum of O �¢ 1 �¢ s in X - ray photoelectron spectroscopy XPS analysis / C atom concentration determined based on the peak spectrum of C �¢ 1 �¢ s in XPS analysis × 100 Cl / C value % = Cl atom concentration determined based on the peak area of the spectrum of C �¢ 12 �¢ p in XPS analysis / C atom concentration determined based on the peak area of the spectrum of C �¢ 1 �¢ s in XPS analysis × 100 S 165 / C value % = S 165 atom concentration based on the peak area of the peak near 165 eV in the spectrum corresponding to S �¢ 2 �¢ p in XPS analysis / C atom concentration determined based on the peak of spectrum of C �¢ 1 �¢ s in XPS analysis × 100.