To provide a carbon material having high capacity and capable of lowering the irreversible capacity at the first cycle of the carbon material for a negative electrode and providing a high mean voltage at the time of combining this material with a positive electrode material, so as to design a secondary battery by burning a hardened material obtained by heating tar or pitch and furfural under the existence of an acid catalyst.
This carbon material for a negative electrode is produced by heating 10 pts.wt. of tar, 0.1-1,000 pts.wt. of furfural preferably 1-100 pts.wt. in the existence of an acid catalyst so as to obtain the hardened material, and burning this hardened material at 800°C or higher. This carbon material can be produced by heating 10 pts.wt. of optical isotropic pitch and 0.1-1,000 pts.wt. of furfural, desirably 1-100 pts.wt., under the existence of the acid catalyst so as to obtain the hardened material, and burning this hardened material at 800°C or higher. As the pitch, a pitch obtained by polymerizing condensation polycyclic hydrocarbon under the existence of hydrogen fluoride and boron trifluoride, or reformed pitch obtained by reforming this pitch can be used.
SUGANO KOICHI
TAKAHASHI YUZURU
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