US 11,855,283 B2
Method for evaluating a characteristic of a nonaqueous electrolyte secondary battery positive electrode active material
Hiroko Oshita, Niihama (JP); Kazuomi Ryoshi, Niihama (JP); Taira Aida, Niihama (JP); Koji Yamaji, Niihama (JP); and Jiro Okada, Niihama (JP)
Assigned to SUMITOMO METAL MINING CO., LTD., Tokyo (JP)
Filed by SUMITOMO METAL MINING CO., LTD., Tokyo (JP)
Filed on Oct. 10, 2022, as Appl. No. 17/962,637.
Application 17/962,637 is a division of application No. 16/760,208, granted, now 11,605,815, previously published as PCT/JP2018/028591, filed on Jul. 31, 2018.
Claims priority of application No. 2017-210306 (JP), filed on Oct. 31, 2017; and application No. 2018-086191 (JP), filed on Apr. 27, 2018.
Prior Publication US 2023/0051717 A1, Feb. 16, 2023
Int. Cl. H01M 4/505 (2010.01); H01M 4/525 (2010.01); H01M 10/0525 (2010.01); C01G 53/00 (2006.01); G01N 15/08 (2006.01); G01N 21/71 (2006.01); G01N 27/416 (2006.01); H01M 4/02 (2006.01)
CPC H01M 4/505 (2013.01) [C01G 53/50 (2013.01); G01N 15/08 (2013.01); G01N 21/71 (2013.01); G01N 27/4167 (2013.01); H01M 4/525 (2013.01); H01M 10/0525 (2013.01); C01P 2004/03 (2013.01); C01P 2004/50 (2013.01); C01P 2004/61 (2013.01); C01P 2004/90 (2013.01); C01P 2006/12 (2013.01); C01P 2006/40 (2013.01); G01N 2015/0846 (2013.01); H01M 2004/021 (2013.01); H01M 2004/028 (2013.01)] 3 Claims
OG exemplary drawing
 
1. A method for evaluating a characteristic of a positive electrode active material for non-aqueous electrolyte secondary batteries,
the positive electrode active material comprising:
a lithium-metal composite oxide powder including a secondary particle configured by aggregating primary particles containing lithium, nickel, manganese, and cobalt, or
a lithium-metal composite oxide powder including both the primary particles and the secondary particle, wherein
the secondary particle has a porous internal structure,
a mixed slurry being a mixture of water and the lithium-metal composite oxide powder as a slurry solid body component has a pH of 11.5 or less at a time when the mixed slurry contains the lithium-metal composite oxide powder at a slurry concentration of 50 [g/L],
the lithium-metal composite oxide powder contains soluble lithium at a content rate of 0.5 [% by mass] or less,
the lithium-metal composite oxide powder has a specific surface area of 3.0 to 4.0 [m2/g], and
the secondary particle has a porosity of more than 50 to 80 [%],
the characteristic being a slurry pH indicating a pH of a slurry containing water and the positive electrode active material as a solid body component,
the method comprising:
adding the positive electrode active material to the water so that the slurry contains the positive electrode active material at a concentration of 50 [g/L];
maintaining a state where the slurry is stirred for 30 minutes; and
obtaining the slurry pH by measuring the pH of the slurry with a pH meter in the state where the slurry is stirred.