LITHIUM METAL COMPOSITE OXIDE, CATHODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY, CATHODE FOR LITHIUM SECONDARY BATTERY, AND LITHIUM SECONDARY BATTERY
A lithium metal composite oxide and the like capable of improving an initial charge and discharge efficiency are provided. In a curve, pores of the lithium metal composite oxide include first pores in which a pore size dp and a maximum pore size dpm satisfy a relationship represented by dp/dpm<0.10, second pores in which the pore size dp and the maximum pore size dpm satisfy a relationship represented by 0.10≤dp/dpm≤0.65, and third pores in which the pore size dp and the maximum pore size dpm satisfy a relationship represented by dp/dpm>0.65. A volume V1 of the first pores, a volume V2 of the second pores, and a volume V3 of the third pores satisfy relationships represented by “0<100·V1/(V1+V2+V3)≤70” and “0<100·V3/(V1+V2+V3)≤15”.
1 . A lithium metal composite oxide comprising:
Li;
Ni; and
an element M,
wherein the element M is at least one element selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Ca, Al, Zn, Sn, Zr, B, Si, Nb, W, Ta, Ba, S and P,
the lithium metal composite oxide has pores, and
in a curve calculated by a Barrett-Joyner-Halenda method from a nitrogen-adsorption isotherm, in which a horizontal axis represents a ratio dp/dpm of a pore size dp to a maximum pore size dpm and a vertical axis represents a cumulative pore volume,
the pores include first pores satisfying a relationship represented by dp/dpm<0.10, second pores satisfying a relationship represented by 0.10≤dp/dpm≤0.65, and third pores satisfying a relationship represented by dp/dpm>0.65, and
a volume V1 of the first pores, a volume V2 of the second pores, and a volume V3 of the third pores satisfy relationships represented by (Expression A1) and (Expression A2),
0
<
100
·
V
1
/
(
V
1
+
V
2
+
V
3
)
≤
70
,
(
Expression
A
1
)
0
<
100
·
V
3
/
(
V
1
+
V
2
+
V
3
)
≤
15.
(
Expression
A
2
)
2 . The lithium metal composite oxide according to claim 1 ,
wherein the lithium metal composite oxide is represented by (Compositional Formula I), in (Compositional Formula I),
M1 is at least one element selected from the group consisting of Mn, Al, and Co,
M2 is at least one element selected from the group consisting of Fe, Cu, Ti, Mg, Ca, Zn, Sn, Zr, B, Si, Nb, W, Ta, Ba, S, and P, and
relationships represented by (Expression Ia) to (Expression Id) are satisfied,
-
0
.
1
≤
α
≤
0.2
,
(
Expression
Ia
)
0
≤
x
≤
0.5
,
(
Expression
Ib
)
0
≤
y
≤
0.7
,
(
Expression
Ic
)
0
<
x
+
y
<
1.
(
Expression
Id
)
3 . The lithium metal composite oxide according to claim 1 ,
wherein a substance amount of Co with respect to a total amount of Ni and the element M is 10% by mole or less.
4 . The lithium metal composite oxide according to claim 2 ,
wherein, in (Compositional Formula I), a relationship represented by (Expression Id_1) is satisfied,
0
<
x
+
y
≤
0.15
.
(
Expression
Id_
1
)
5 . The lithium metal composite oxide according to claim 1 ,
wherein, in a pore size distribution calculated by the Barrett-Joyner-Halenda method from the nitrogen-adsorption isotherm, an average pore size Adp satisfies a relationship represented by (Expression B),
10
nm
≤
Adp
≤
40
nm
.
(
Expression
B
)
6 . The lithium metal composite oxide according to claim 1 ,
wherein, in a pore size distribution calculated by the Barrett-Joyner-Halenda method from the nitrogen-adsorption isotherm, a pore volume VP satisfies a relationship represented by (Expression C),
0.001
cm
3
/
g
≤
V
P
≤
0.01
cm
3
/
g
.
(
Expression
C
)
7 . The lithium metal composite oxide according to claim 1 ,
wherein a metal site occupancy factor SR obtained from Rietveld analysis satisfies a relationship represented by (Expression D),
1.
%
≤
SR
≤
4.
%
.
(
Expression
D
)
8 . The lithium metal composite oxide according to claim 1 ,
wherein an average crystallite size AK obtained from Rietveld analysis satisfies a relationship represented by (Expression E),
80
nm
≤
A
K
≤
200
nm
.
(
Expression
E
)
9 . The lithium metal composite oxide according to claim 1 ,
wherein a BET specific surface area BS satisfies a relationship represented by (Expression F),
0.2
m
2
/
g
≤
BS
≤
2.
m
2
/
g
.
(
Expression
F
)
10 . A cathode active material for lithium secondary battery, comprising:
the lithium metal composite oxide according to claim 1 .
11 . A cathode for lithium secondary battery, comprising:
the cathode active material for lithium secondary battery according to claim 10 .
12 . A lithium secondary battery comprising:
the cathode for lithium secondary battery according to claim 11 .