Positive electrode active material for lithium ion secondary battery, method for producing the same, and lithium ion secondary battery
AssigneeSumitomo Metal Mining Co., Ltd.
InventorsYuki Koshika, Haruki Kaneda
Life of this patent
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Abstract
A positive electrode active material for a lithium ion secondary battery, in which a lithium-nickel-manganese composite oxide has a hexagonal layered structure, a mole number ratio of metal elements is represented as Li:Ni:Mn:M:Ti=a:(1−x−y−z):x:y:z, provided that 0.97≤a≤1.25, 0.05≤x≤0.15, 0≤y≤0.15, and 0.01≤z≤0.05, a ratio of a total amount of peak intensities of most intense lines of a titanium compound to a (003) diffraction peak intensity in XRD measurement is 0.2 or less, and a volume resistivity as determined by powder compact resistivity measurement compressed to 4.0 g/cm3 is 1.0×102 Ω·cm or more and 1.0×104 Ω·cm or less.
Claims9
A positive electrode active material for a lithium ion secondary battery, comprising a lithium-nickel-manganese composite oxide configured by secondary particles with a plurality of aggregated primary particles,
- wherein the lithium-nickel-manganese composite oxide has a hexagonal layered structure and contains lithium (Li), nickel (Ni), manganese (Mn), an element M (M) that is at least one element selected from the group consisting of Co, V, Mg, Mo, Nb, Ca, Cr, Zr, Ta, and Al, and titanium (Ti) as metal elements,
- a mole number ratio of the metal elements is represented as Li:Ni:Mn:M:Ti=a:(1−x−y−z):x:y:z, provided that 0.97≤a≤1.25, 0.05≤x≤0.15, 0≤y≤0.15, and 0.01≤z≤0.05,
- a ratio of a total amount of peak intensities of most intense lines of a titanium compound to a (003) diffraction peak intensity that is the most intense line of a hexagonal layered structure in XRD measurement of the positive electrode active material is 0.2 or less, and
- a volume resistivity as determined by powder compact resistivity measurement compressed to 4.0 g/cm3 is 1.0×102 Ω·cm or more and 1.0×104 Ω·cm or less.
A method for producing a positive electrode active material for a lithium ion secondary battery which contains a lithium-nickel-manganese composite oxide configured by secondary particles with a plurality of aggregated primary particles, the method comprising:
- mixing at least a nickel-manganese composite compound, a titanium compound, and a lithium compound to obtain a mixture;
- and
- firing the mixture in an oxidizing atmosphere having an oxygen concentration of 80 vol % or more and 100 vol % or less at 750° C. or higher and 1000° C. or lower so as to obtain the lithium-nickel-manganese composite oxide,
- wherein the nickel-manganese composite compound contains nickel (Ni), manganese (Mn), and an element M (M) that is at least one element selected from the group consisting of Co, V, Mg, Mo, Nb, Ca, Cr, Zr, Ta, and Al as metal elements, and a mole number ratio of the metal elements is represented as Ni:Mn:M=(1−x−y):x:y, provided that 0.05≤x≤0.15 and 0≤y≤0.15,
- a ratio (Li/Me) of a lithium mole number (Li) to a total mole number (Me) of nickel, manganese, the element M, and titanium contained in the mixture is 0.97 or more and 1.25 or less, and a ratio (Ti/Me) of a titanium mole number (Ti) to the total mole number (Me) is 0.01 or more and 0.05 or less, and
- a ratio of a total amount of peak intensities of most intense lines of the titanium compound to a (003) diffraction peak intensity that is the most intense line of a hexagonal layered structure in XRD measurement of the positive electrode active material is 0.2 or less.
Dependencies are inferred from the claim text.