| 摘要 |
PROBLEM TO BE SOLVED: To improve cycle life, by using, as a negative electrode material, a compound including silicon atoms which Li can be inserted into or discharged from, and, as a positive electrode active material, a Li-containing transition metal composite oxide including a fixed metal, having an α-NaFeO2 type layered structure, and having specified contents of alkaline earth metal elements and sulfur. SOLUTION: For a negative electrode material, simple silicon, a silicon alloy, or a silicide is used as a compound which Li can be inserted into or discharged from. For a positive electrode active material, a Li-containing transition metal composite oxide including metal of one kind or more selected from Co, Ni, Mn, and Fe, and having a layered structure of LiMnO4 oxide of a spinel structure of an α-NaFeO2 type or an A[B2 ]O4 type, and impurities getting mixed in the positive electrode active material are specified to have an alkaline earth metal element content of 0.1 wt.% or less, a sulfur content of 0.1 wt.% or less, and a percentage water content of about 0.5 or less. |
