ELECTRODE ACTIVE MATERIAL, SECONDARY BATTERY, AND ELECTRIC APPARATUS
An electrode active material includes a layered metal oxide. The layered metal oxide has the following general formula: Na x M1 a M2 b Mn 1-a-b O 2-z F z ; where 0.55≤x≤0.85, a≥0, b≥0, 0.1≤a+b≤0.33, and 0.06≤z/(1−a−b)≤0.13; M1 is selected from one or more of alkali metal elements other than Na and alkaline earth metal elements; and M2 is selected from one or more of transition metal elements other than Mn.
1 . An electrode active material, comprising a layered metal oxide, wherein the layered metal oxide has the following general formula:
wherein:
0
.
5
5
≤
x
≤
0
.
8
5
,
a
≥
0
,
b
≥
0
,
0.1
≤
a
+
b
≤
0.33
,
and
0.06
≤
z
/
(
1
-
a
-
b
)
≤
0.13
;
M1 is selected from one or more of alkali metal elements other than Na and alkaline earth metal elements; and
M2 is selected from one or more of transition metal elements other than Mn.
2 . The electrode active material according to claim 1 , wherein the layered metal oxide is a P2-type layered metal oxide.
3 . The electrode active material according to claim 1 , having one or more of following characteristics:
the alkali metal element is selected from Li, K, or a combination thereof;
the alkaline earth metal element is selected from Be, Mg, Ca, Sr, Ba, or a combination thereof; and
the transition metal element is selected from Ni, Fe, Ti, Cr, Co, Cu, Zn, or a combination thereof.
4 . The electrode active material according to claim 1 , having one or more of following characteristics:
the alkali metal element is Li;
the alkaline earth metal element is Mg; and
the transition metal element is selected from Ni, Fe, Zn, or a combination thereof.
5 . The electrode active material according to claim 1 , having one or more of following characteristics:
0
.
6
5
≤
x
≤
0.75
;
and
0.06
≤
z
/
(
1
-
a
-
b
)
≤
0
.
0
8
.
6 . The electrode active material according to claim 1 , wherein 0.25≤(a+b)/(1−a−b)≤0.43.
7 . The electrode active material according to claim 1 , wherein in an X-ray diffraction pattern of the layered metal oxide, an intensity corresponding to a (002) crystal plane characteristic peak satisfies following relation:
I/I 0 ≥0.8, where:
I 0 is an intensity corresponding to a (002) crystal plane characteristic peak of a layered metal oxide not soaked in water; and
I is an intensity corresponding to a (002) crystal plane characteristic peak of a layered metal oxide soaked in water for 24 hours.
8 . The electrode active material according to claim 1 , comprising:
a core, wherein the core comprises the layered metal oxide; and
a shell, wherein the shell covers at least a portion of surface of the core, the shell comprises a first element A, and the first element A is selected from Ti, Al, Mg, Co, or a combination thereof;
wherein the electrode active material has following general formula:
where n>0.
9 . The electrode active material according to claim 8 , wherein the electrode active material satisfies following relation:
0
<
n
≤
0
.0006
/
z
.
10 . A secondary battery, comprising a positive electrode, wherein the positive electrode comprises the electrode active material according to claim 1 .
11 . An electric apparatus, comprising the secondary battery according to claim 10 .