| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lithium secondary battery which can prevent a capacity rate and an output maintaining rate from decreasing with charge-discharge cycles, and has a long life. <P>SOLUTION: A positive electrode plate which uses lithium cobalt oxide with a layered crystal structure as an anode active substance, and a negative electrode plate which uses graphite as a cathode active substance and has an electrode area B of 0.74 m<SP>2</SP>, are manufactured. The positive electrode plate and the negative electrode plate are combined with each other through a separator and rolled, and are dipped into a nonaqueous electrolyte for a lithium ion battery to be completed. The nonaqueous electrolyte is prepared by dissolving LiPF<SB>6</SB>of 1 mol/liter and manganese phosphate hexafluoride into a mixture solvent of EC, DMC, and DEC. In that case, a manganese ion concentration A is adjusted so as to be 100 to 200 ppm, and the abundance ratio A/B of the manganese ion concentration to the electrode area of the negative electrode plate is 135 to 270 before initial charging. The initial charging helps manganese deposited on a negative electrode surface to decompose the nonaqueous electrolyte and makes a coating film stable in charging and discharging the battery. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
