NOVELTY - A positive electrode (1) has a positive electrode collector (2) and a positive electrode active material layer (3) formed on the surface of the positive electrode collector. The positive electrode active material layer comprising lithium carbonate and lithium-containing nickel oxide (I). The positive electrode active material layer has high concentration region where the concentration of lithium carbonate is high, and low concentration region where the concentration of lithium carbonate is low.    USE - Positive electrode is used for lithium ion secondary battery (claimed) used as power supply for electric vehicle, hybrid car, electric tool, electric-power-assisted bicycle and power supply for load leveling.    ADVANTAGE - The lithium ion secondary battery using positive electrode has excellent input-output characteristics, durability and reliability.    DETAILED DESCRIPTION - A positive electrode has a positive electrode collector and a positive electrode active material layer formed on the surface of the positive electrode collector. The positive electrode active material layer comprising lithium carbonate and lithium-containing nickel oxide of formula: LixNi1-(p+q+r)CopAlqMrO2+y (I), where M is transition element excluding nickel and cobalt, magnesium, calcium, zinc and/or bismuth, x is 0.8-1.4, y is -0.1 to 0.1, and p+q+r is more than 0 to 0.7. The positive electrode active material layer has high concentration region where the concentration of lithium carbonate is high, and low concentration region where the concentration of lithium carbonate is low. The high concentration region occupies 2-80% of the total thickness of positive electrode active material layer from the surface. The low concentration region occupies the remaining at the side of positive electrode collector of positive electrode active material layer. INDEPENDENT CLAIMS are included for the following:    (1) manufacture of positive electrode; and    (2) lithium ion secondary battery.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of positive electrode.    Positive electrode (1)    Positive electrode collector (2)    Positive electrode active material layer (3)    Inner layer (4)    Outer layer (5)