Positive electrode active material for lithium secondary cell and lithium secondary cell
AssigneeGS Yuasa Corporation
InventorsRyuji Shiozaki, Akihiro Fujii, Kazuya Okabe, Toshiyuki Nukuda
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Abstract
A positive active material for lithium secondary batteries, includes a composite oxide including an oxide which is represented by the composite formula LixMnaNibCocO2 and has an α-NaFeO2 structure, and an impurity phase including Li2MnO3. The values a, b, and c are within such a range that in a ternary phase diagram showing the relationship among these, (a, b, c) is present on the perimeter of or inside the quadrilateral ABCD defined by point A (0.5, 0.5, 0), point B (0.55, 0.45, 0), point C (0.55, 0.15, 0.30), and point D (0.15, 0.15, 0.7) as vertexes, and 0.95<x/(a+b+c)<1.35.
Claims20
A positive active material for lithium secondary batteries, comprising:
- a composite oxide comprising:
- an oxide which is represented by the composite formula LixMnaNibCocO2 and has an α-NaFeO2 structure;
- and
- an impurity phase comprising Li2MnO3,
- wherein a, b, and c are values within such a range that in a ternary phase diagram showing the relationship among these, (a, b, c) is present on the perimeter of or inside the quadrilateral ABCD defined by point A (0.5, 0.5, 0), point B(0.55, 0.45, 0), point C (0.55, 0.15, 0.30), and point D(0.15, 0.15, 0.7) as vertexes, and 0.95<x/(a+b+c)<1.35.
Dependencies are inferred from the claim text.