Patent ID: 8492032

Claim:
A cathode active material for a lithium secondary cell, comprising a lithium transition metal oxide with an α-NaFeO 2 layered crystalline structure in which the transition metal comprises a transition metal mixture of Ni and Mn, an average oxidation number of all transition metals other than lithium is more than +3, and specific conditions represented by the following Formulae (1) and (2) are satisfied 1.0 <m (Ni)/ m (Mn) (1) m (Ni 2+ )/ m (Mn 4+ )<1 (2) wherein m(Ni)/m(Mn) represents a molar ratio of nickel to manganese and m(Ni 2+ )/m(Mn 4+ ) represents a molar ratio of Ni 2+ to Mn 4+ .