| CPC H01M 4/366 (2013.01) [H01M 4/483 (2013.01); H01M 10/0525 (2013.01); H01M 2004/028 (2013.01)] | 2 Claims |

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1. A positive electrode active material, comprising:
a core portion which contains a lithium transition metal composite oxide; and
a coat portion with which at least part of a surface of the core portion is coated, wherein:
the coat portion contains brookite-type TiO2 and rutile-type TiO2, and does not contain anatase-type TiO2,
a presence ratio (A/B) between an amount of presence (A) of Ti serving as the brookite-type TiO2 in the coat portion and an amount of presence (B) of Ti serving as the rutile-type TiO2 in the coat portion which is calculated based on Ti peak analysis by XAFS is 0.15 to 2.0,
an amount of a metallic element except an alkali metal element contained in the core portion which is calculated based on ICP analysis on a molar basis is assumed to be 100 parts, and
an amount of Ti serving as the brookite-type TiO2 and the rutile-type TiO2 in the coat portion is 0.5 to 5.0 parts.
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