| abstract |
There is provided a lithium ion secondary battery with a high capacity and having excellent cycle characteristics. The lithium ion secondary battery, including a positive electrode, a negative electrode, a separator and a nonaqueous electrolyte liquid. Here, the positive electrode comprises a positive electrode material in which a surface of particles of a positive electrode active material is coated with an Al-containing oxide. The Al-containing oxide has an average coating thickness of 5 to 50 nm. The positive electrode active material contained in the positive electrode material comprises a lithium cobalt oxide comprising Co and at least one kind of an element M 1 selected from the group consisting of Mg, Zr, Ni, Mn, Ti and Al. The negative electrode comprises a material S including SiO x (0.5≦x≦1.5) as a negative electrode active material, wherein in 100 mass % of a total of the negative electrode active material included in the negative electrode, the materials S is included in the negative electrode active material at a content of 10 mass % or more. |