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

摘要

This carbon material for lithium ion secondary batteries is a carbon material used in lithium ion secondary batteries, which is characterized by: containing graphite that serves as the base material and hard carbon; satisfying the relation of 1.2 <= A/B <= 19 when the graphite content is represented by A (% by weight) and the hard carbon content is represented by B (% by weight); and having a graphite content of from 55% by weight to 95% by weight (inclusive). Consequently, the present invention is able to provide: a carbon material for lithium ion secondary batteries, which is capable of providing a lithium ion secondary battery that has high charge and discharge capacity and excellent charge and discharge efficiency in a balanced manner; a negative electrode material for lithium ion secondary batteries; and a lithium ion secondary battery which has the above-mentioned characteristics. In this connection, it is preferable that the hard carbon is contained in an amount of from 5% by weight to 45% by weight (inclusive).