NOVELTY - A lithium ion secondary battery consists of a positive electrode, a separator, a negative electrode, and an exterior component (8). The negative electrode comprises metal silicon as active material and a binder, and is doped with lithium. The ratio of amount of lithium to be inserted into the negative electrode before the electric potential of negative electrode with respect to metal lithium reaches 0.02 V, and the amount of lithium to be released from the positive electrode before the electric potential of positive electrode reaches 4.3 V is 1.2-1.9.    USE - Lithium ion secondary battery. Uses include but are not limited to mobile telephones, notebook personal computers, electric vehicles, engine drives, electrical storage applications combined with solar cells, industrial apparatus, and consumer application apparatus.    ADVANTAGE - The lithium ion secondary battery has high energy density and excellent cycle characteristics.    DETAILED DESCRIPTION - A lithium ion secondary battery consists of a positive electrode, a separator, a negative electrode, and an exterior component. The negative electrode comprises metal silicon as active material and a binder, and is doped with lithium. The ratio of amount (Ma: number of atoms) of lithium to be inserted into the negative electrode before the electric potential of negative electrode with respect to metal lithium reaches 0.02 V, and the amount (Mc: number of atoms) of lithium to be released from the positive electrode before the electric potential of positive electrode reaches 4.3 V is 1.2-1.9. The ratio of Ma with respect to sum total of Mc and amount (MLi: number of atoms) of lithium doped into the negative electrode is greater than 1 and less than 1.6. An INDEPENDENT CLAIM is included for manufacture of lithium ion secondary battery.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of the lithium ion secondary battery.    Negative-electrode active-material layer (1)    Negative-electrode collector (2)    Positive-electrode active-material layer (3)    Positive-electrode collector (4)    Exterior component (8)