Abstract
Lithium secondary batteries using carbon as negative electrode based on Li insertion have been developed. In the present paper vapor-grown carbon fibers (VGCF), as an ideal carbon material in structure, with different crystallographic structure are applied as a negative electrode for the lithium secondary batteries with 1 mol LiClO4/propylene carbonate electrolyte. The battery performances of the fibrous electrode are characterized as a function of the microscopic structure of the carbon fibers. And the c-axis repeat distances of the TEM pictures of lithium charged as well as the host carbon fibers are treated by using image analysis system. It is shown that Li are stored to form the 1st stage three dimensional intercalation compounds in well-ordered VGCF, on the contrary, in disordered VGCF electrodes Li are inserted between carbon layers. VGCF has been evaluated as one of the promising negative electrode material for Li secondary battery.
