CPC H01M 4/505 (2013.01) [C01G 53/50 (2013.01); H01M 4/525 (2013.01); H01M 10/0525 (2013.01); C01P 2004/03 (2013.01); H01M 2004/021 (2013.01); H01M 2004/028 (2013.01)] | 20 Claims |
1. A positive electrode active material for a non-aqueous electrolyte secondary battery, the positive electrode active material comprising:
a lithium-transition metal composite oxide containing lithium, nickel, cobalt, and manganese, and having a layered structure,
wherein the lithium-transition metal composite oxide has a ratio D50/DSEM that is from 1 to 4, wherein D50 is a 50% particle diameter in a cumulative particle size distribution on a volumetric basis and DSEM is an average particle diameter based on electron microscope observation,
a disorder of elemental nickel that is 3% or less, and
the lithium-transition metal composite oxide has a composition with
a ratio of a number of moles of cobalt to the total number of moles of the metals other than lithium that is less than 0.2,
a ratio of a number of moles of manganese to the total number of moles of the metals other than lithium that is less than 0.2, and
a ratio of the number of moles of manganese to a sum of the number of moles of cobalt and the number of moles of manganese that is less than 0.4.
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