NOVELTY - A lithium ion secondary battery (100) consists of a positive electrode, a negative electrode, and a nonaqueous electrolyte. The positive electrode comprises lithium-nickel-cobalt-manganese-zirconium/niobium/aluminum (element M)-tungsten/molybdenum (element M") complex as active material. When the active-material powder (2 g) and pure water (100 g) are stirred into a suspension liquid and filtered, the elution amount of element (M") per 1 g of filtrate calculated by inductively coupled plasma source mass spectrometry of the filtrate is 0.025 mmol or less.    USE - Lithium ion secondary battery is used for vehicles (claimed) e.g. hybrid vehicles and electric vehicles, such as car.    ADVANTAGE - The lithium ion secondary battery has excellent output characteristics (at low and normal temperatures), high-temperature durability, and cycle characteristics, and high capacity maintenance factor, and low internal resistance.    DETAILED DESCRIPTION - A lithium ion secondary battery consists of a positive electrode, a negative electrode, and a nonaqueous electrolyte. The positive electrode comprises lithium-nickel-cobalt-manganese-zirconium/niobium/aluminum-tungsten/molybdenum complex of formula: LixNiaCobMncM'dM"eO2, where M' is zirconium, niobium and/or aluminum, M" is tungsten and/or molybdenum, x is 1-1.25, a+b+c+d+e is 1, and (d+e) is 0.001-0.02, as active material. When the active-material powder (2 g) and pure water (100 g) are stirred into a suspension liquid and the suspension liquid is filtered, the elution amount of element (M") per 1 g of filtrate calculated by inductively coupled plasma source mass spectrometry of the filtrate is 0.025 mmol or less. An INDEPENDENT CLAIM is included for manufacture of positive-electrode active material.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of the external shape of the lithium ion secondary battery. (Drawing includes non-English language text)    Battery case (10)    Cover (14)    Positive-electrode terminal (38)    Negative-electrode terminal (48)    Lithium ion secondary battery (100)