NOVELTY - A lithium ion secondary battery (100) consists of a positive electrode (120) containing a positive electrode active material, a negative electrode (130) containing a negative electrode active material, an electrolyte solution containing nonaqueous solvent and lithium salt, and a coating film formed on the surface of the positive electrode. The coating film contains lithium-containing phosphorus compound. The concentration ratio (Li/P) of lithium and phosphorus in the lithium-containing phosphorus compound is 0.3-4.    USE - Lithium ion secondary battery is used for hybrid vehicle, electric vehicle and consumer appliance.    ADVANTAGE - The lithium ion secondary battery operates at high voltage, and has high cycle characteristics.    DETAILED DESCRIPTION - A lithium ion secondary battery consists of a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, an electrolyte solution containing nonaqueous solvent and lithium salt, and a coating film formed on the surface of the positive electrode. The coating film contains lithium-containing phosphorus compound. The concentration ratio (Li/P) of lithium and phosphorus in the lithium-containing phosphorus compound is 0.3-4. The concentration ratio (M/P) of transition metal (M) contained on the surface of the positive electrode and phosphorus in the film is less than 1. INDEPENDENT CLAIMS are included for the following:    (1) positive electrode active material; and    (2) manufacture of lithium ion secondary battery, which involves accommodating the positive electrode and the negative electrode in the battery exterior, injecting the electrolyte solution containing silicon-containing compound (B) of formula: H3C-Si(-R11)(-R13)-R12, charging, and aging at 35-60 degrees C for 24-240 hours.    R11-R13=organic group.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional schematic view of the lithium ion secondary battery.    Lithium ion secondary battery (100)    Separator (110)    Positive electrode (120)    Negative electrode (130)    Positive electrode electrical power collector (140)