CPC H01M 4/505 (2013.01) [C01G 53/006 (2013.01); C01G 53/40 (2013.01); C01G 53/42 (2013.01); C01G 53/50 (2013.01); H01M 4/131 (2013.01); H01M 4/1391 (2013.01); H01M 4/485 (2013.01); H01M 4/525 (2013.01); H01M 10/0525 (2013.01); C01P 2004/03 (2013.01); C01P 2004/51 (2013.01); C01P 2004/61 (2013.01); C01P 2006/40 (2013.01); H01M 10/052 (2013.01)] | 14 Claims |
1. A method of producing a positive electrode active material for a nonaqueous electrolyte secondary battery, comprising:
providing nickel-containing composite oxide particles;
subjecting a first mixture containing the nickel-containing composite oxide particles and a lithium compound to a first heat treatment at a first temperature and a second heat treatment at a second temperature higher than the first temperature to obtain a first heat-treated material; and
dissociating from the first heat-treated material the positive electrode active material,
wherein the positive electrode active material comprises lithium-transition metal composite oxide particles having a ratio 2D50/2DSEM of a 50% particle size 2D50 in volume-based cumulative particle size distribution to an average particle size 2DSEM based on electron microscopic observation in a range of 1 to 4,
wherein the lithium-transition metal composite oxide particles have a ratio 2D90/2D10 of a 90% particle size 2D90 to a 10% particle size 2D10 in volume-based cumulative particle size distribution is 4 or less, and
wherein a molar ratio of nickel in a composition of the lithium-transition metal composite oxide to a total molar number of metals other than lithium is 0.3 to 0.6.
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