| 摘要 |
According to the present invention, a nonaqueous electrolyte secondary battery prepared from a carbon material obtained from inexpensive petroleum heavy oil, having a high capacity, and excelling in high-temperature cyclability, the carbon material, and a precursor for the carbon material can be provided. The precursor for the carbon material is obtained from certain petroleum heavy oil by holding the petroleum heavy oil under a pressure of 2.0 MPa or less at a temperature of 400-600° C. for three hours or more. The carbon material is treating the precursor with heat at 800-1,500° C. The nonaqueous electrolyte secondary battery is obtained by using, as a negative electrode active material, a carbon material obtained by further oxidizing said carbon material at 200-1,000° C. in nitrogen, argon, or a mixture thereof containing an oxidizing gas, or in the atmospheric air.
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