CARBON MATERIAL FOR LITHIUM ION SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide an anode material capable of obtaining a lithium ion secondary battery in which a charge/discharge irreversible capacity is sufficiently small as seen at an initial cycle and excellent high-temperature preservation characteristics are endowed, and gas generation at the initial cycle and at a high temperature preservation can be reduced.

SOLUTION: The carbon material for a lithium ion secondary battery has 1% or more and 4% or less of an O/C value of a surface functional group amount as shown in the following formula 1 and moreover has 0.05% or more and 0.5% or less of a total (C1/C+S165/C) of values of the surface functional group amount C1/C as shown in the following formula 2 and the surface function group amount S165/C as shown in the following formula 3. Formula 1: A value of O/C(%)= O atom concentration obtained based on a peak area of a spectrum of O1s in an X-ray photoelectron spectroscopy (XPS) analysis/C atom concentration × 100 obtained based on a peak area of a spectrum of C1s in the XPS analysis. Formula 2: A value of C1/C(%)= C1 atom concentration obtained based on a peak area of a spectrum of C12p in the XPS analysis/C atom concentration × 100 obtained based on a peak area of a spectrum of C1s in the XPS analysis. Formula 3: A value of S165/C(%) = S165atom concentration obtained based on a peak area of a peak in the vicinity of 165eV in a spectrum corresponding to S2p in the XPS analysis/C atom concentration × 100 obtained based on a peak area of a spectrum of C1s in the XPS analysis.

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