CPC H01M 4/131 (2013.01) [C01G 53/50 (2013.01); H01M 4/134 (2013.01); H01M 4/364 (2013.01); H01M 4/505 (2013.01); H01M 4/525 (2013.01); H01M 10/0525 (2013.01); C01P 2002/74 (2013.01); H01M 2004/028 (2013.01)] | 27 Claims |
1. A positive electrode active material comprising:
a lithium composite oxide, wherein
the lithium composite oxide is a multiphase mixture including:
a first phase having a crystal structure belonging to a monoclinic crystal;
a second phase having a crystal structure belonging to a hexagonal crystal; and
a third phase having a crystal structure belonging to a cubic crystal,
the positive electrode active material satisfies the following mathematical expression (I):
0.08≤ integrated intensity ratio I(20°-23°)/I(18°-20°)≤0.25, where
the integrated intensity ratio II(20°-23°)/I(18°-20°) is equal to a ratio of an integrated intensity I(20°-23°) to an integrated intensity I(18°-20°),
the integrated intensity I(18°-20°) is an integrated intensity of a first maximum peak present in a diffraction angle 2θ range of greater than or equal to 18° and less than or equal to 20° in an X-ray diffraction pattern of the lithium composite oxide, and
the integrated intensity I(20°-23°) is an integrated intensity of a second maximum peak present in a diffraction angle 2θ range of greater than or equal to 20° and less than or equal to 23° in the X-ray diffraction pattern of the lithium composite oxide, and
the positive electrode active material satisfies the following mathematical expression (II):
0.81≤ integrated intensity ratio I(18°-20°)/I(43°-46°)≤1.26,
where, the integrated intensity ratio I(18°-20°)/I(43°-46°)is equal to a ratio of an integrated intensity I(18°-20°) to an integrated intensity I(43°-46°),
the integrated intensity I(18°-20°) is an integrated intensity of a first maximum peak present in a diffraction angle 2θ range of greater than or equal to 18° and less than or equal to 20° in the X-ray diffraction pattern of the lithium composite oxide, and
the integrated intensity I(43°-46°) is an integrated intensity of a third maximum peak present in a diffraction angle 2θ range of greater than or equal to 43° and less than or equal to 46° in the X-ray diffraction pattern of the lithium composite oxide.
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