NOVELTY - Lithium ion secondary cell has a positive electrode active material which is a complex oxide having crystal structure formed by laminating lithium layer containing lithium ion, oxygen layer containing oxide ion and transition metal layer containing nickel, cobalt and manganese. The negative electrode active material contains carbon material as main component. The non-aqueous electrolyte contains anion compound (2) dissolved in an organic solvent.    USE - Used for hybrid vehicles or electric vehicles.    ADVANTAGE - The lithium ion secondary cell which maintains high discharge capacitance and high output even after repeated charging and discharging is provided. The lithium ion secondary cell smoothly carries out storage and discharge of lithium ion. The raise in internal resistance of the cell is suppressed and reduction in charging and discharging cycle characteristics is suppressed.    DETAILED DESCRIPTION - Lithium ion secondary cell (1) has positive electrode (2) containing positive electrode active material, negative electrode (3) containing negative electrode active material and non-aqueous electrolyte formed by dissolving the electrolyte in an organic solvent. The positive electrode active material is a complex oxide which has crystal structure formed by laminating lithium layer containing lithium ion, oxygen layer containing oxide iron and transition metal layer containing nickel, cobalt and manganese. The negative electrode active material contains carbon material as main component. The non-aqueous electrolyte contains anion compound of general formula (2). The complex oxide of positive electrode active material has formula: Li1+x(Ni1/3\|~d1Co1/3\|~d2Mn1/3\|~d3)1-xO2.    x=0.1-0.2;    delta1-delta3=0-0.1;    M=transition metal or element chosen from groups (III,IV or V) of periodic table;    b=1-3;    m=1-4;    n=0-8;    q=0 or 1;    R1=1-10C alkylene or halogenated alkylene, 6-20C arylene or halogenated arylene, and the alkylene and arylene optionally have substitutent and heteroatom in the structure;    R2=halogen, 1-10C alkyl or halogenated alkyl, 6-20C aryl or halogenated aryl or X3R3, and alkyls and aryls are optionally substituted or has heteroatom in the structure;    X1-X3=oxygen, sulfur or NR4;and    R3,R4=hydrogen, 1-10C alkyl or halogenated alkyl, 6-20C aryl or halogenated aryl or X3R3, and alkyls and aryls are optionally substituted or has heteroatom in the structure, and two of R3 and R4 optionally couple to form a ring.    DESCRIPTION OF DRAWING(S) - The figure shows the explanatory drawing of the structure of lithium ion secondary cell. (Drawing includes non-English language text)    Lithium ion secondary cell (1)    Positive electrode (2)    Negative electrode (3)    Separator (4)    Battery case (6)