POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY, POSITIVE ELECTRODE FOR LITHIUM SECONDARY BATTERY, AND LITHIUM SECONDARY BATTERY
This positive electrode active material for a lithium secondary battery contains a lithium metal composite oxide containing at least Li and Ni, and satisfies (1) and (2): (1) a pore volume in a range of pore diameter of 2 to 10 nm is 9.0×10 −4 cm 3 /g or less in a pore diameter distribution in an adsorption isotherm as determined by measurement of an adsorption isotherm and a desorption isotherm of nitrogen gas and a Barrett-Joyner-Halenda method; and (2) a pore diameter at which a log differential pore volume is a maximum value in a log differential pore volume distribution in a range of pore diameter of 2 to 200 nm based on a pore diameter distribution in a desorption isotherm as determined by measurement of an adsorption isotherm and a desorption isotherm of nitrogen gas and a Barrett-Joyner-Halenda method is more than 10 nm and 200 nm or less.
1 . A positive electrode active material for a lithium secondary battery, comprising a lithium metal composite oxide containing at least Li and Ni, and satisfying (1) and (2):
(1) a pore volume in a range of pore diameter of 2 to 10 nm is 9.0×10 −4 cm 3 /g or less in a pore diameter distribution in an adsorption isotherm as determined by measurement of an adsorption isotherm and a desorption isotherm of nitrogen gas and a Barrett-Joyner-Halenda method; and
(2) a pore diameter at which a log differential pore volume is a maximum value in a log differential pore volume in a range of pore diameter of 2 to 200 nm based on a pore diameter distribution in a desorption isotherm as determined by measurement of an adsorption isotherm and a desorption isotherm of nitrogen gas and a Barrett-Joyner-Halenda method is more than 10 nm and 200 nm or less.
2 . The positive electrode active material for the lithium secondary battery according to claim 1 ,
wherein the lithium metal composite oxide is represented by Formula (A),
Li[Li m (Ni (1−n )X n ) 1−m ]O 2 (A)
(in Formula A, X represents one or more elements selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, V, B, Si, and P, and −0.1≤m≤0.2 and 0≤n≤0.7 are satisfied.)
3 . The positive electrode active material for the lithium secondary battery according to claim 1 ,
wherein a maximum value of log differential pore volume in a range of pore diameter of 5 nm or less is less than 0.005 cm 3 /g in the pore diameter distribution in the desorption isotherm.
4 . The positive electrode active material for the lithium secondary battery according to claim 1
further comprising Na,
wherein a product of a proportion of a mass of Na to a total mass of the positive electrode active material for the lithium secondary battery and a BET specific surface area of the positive electrode active material for the lithium secondary battery is 2.0×10 −4 m 2 /g or less.
5 . The positive electrode active material for the lithium secondary battery according to claim 1 ,
wherein a pore volume in a range of pore diameter of 2 to 200 nm is 2.0×10 −3 cm 3 /g or more in the pore diameter distribution in the desorption isotherm.
6 . The positive electrode active material for the lithium secondary battery according to claim 1 ,
wherein a BET specific surface area of 0.5 m 2 /g or more and less than 1.2 m 2 /g.
7 . The positive electrode active material for the lithium secondary battery according to claim 1 ,
wherein a value of S/(V×1000) is less than 0.30 m 2 /cm 3 , where S is a BET specific surface area of the positive electrode active material for the lithium secondary battery, and V is a pore volume in a range of pore diameter of 2 to 200 nm.
8 . A positive electrode for a lithium secondary battery, comprising:
the positive electrode active material for the lithium secondary battery according to claim 1 .
9 . A lithium secondary battery, comprising:
the positive electrode for the lithium secondary battery according to claim 8 .
10 . The positive electrode active material for the lithium secondary battery according to claim 2 ,
wherein a maximum value of log differential pore volume in a range of pore diameter of 5 nm or less is less than 0.005 cm 3 /g in the pore diameter distribution in the desorption isotherm.
11 . The positive electrode active material for the lithium secondary battery according to claim 2 ,
further comprising Na,
wherein a product of a proportion of a mass of Na to a total mass of the positive electrode active material for the lithium secondary battery and a BET specific surface area of the positive electrode active material for the lithium secondary battery is 2.0×10 4 m 2 /g or less.
12 . The positive electrode active material for the lithium secondary battery according to claim 2 ,
wherein a pore volume in a range of pore diameter of 2 to 200 nm is 2.0×10 −3 cm 3 /g or more in the pore diameter distribution in the desorption isotherm.
13 . The positive electrode active material for the lithium secondary battery according to claim 2 ,
wherein a BET specific surface area of 0.5 m 2 /g or more and less than 1.2 m 2 /g.
14 . The positive electrode active material for the lithium secondary battery according to claim 2 ,
wherein a value of S/(V×1000) is less than 0.30 m 2/ cm 3 , where S is a BET specific surface area of the positive electrode active material for the lithium secondary battery, and V is a pore volume in a range of pore diameter of 2 to 200 nm.
15 . A positive electrode for a lithium secondary battery, comprising:
the positive electrode active material for the lithium secondary battery according to claim 2 .
16 . A lithium secondary battery, comprising:
the positive electrode for the lithium secondary battery according to claim 15 .