Polyanionic compound and preparation method therefor, positive electrode material, positive electrode sheet, secondary battery, and electronic device

Patent metadata

Field	Value
Publication number	US-2025260012-A1
Application number	US-202519195785-A
Country	US
Kind code	A1
Filing date	May 1, 2025
Priority date	Nov 4, 2022
Publication date	Aug 14, 2025
Grant date	—

Abstract

A polyanionic compound has the following chemical formula: Na 2+x Mn 1−y M y Si 2−z M′ z O 6−t N k X p Y q (1), where in formula (1), M is selected from Ni, Fe, Cu, Zn, Mg, Al, or a combination thereof, M′ is selected from Ge, Sn, Ti, or a combination thereof, X is selected from S, Se, or a combination thereof, and Y is selected from F, Cl, or a combination thereof, where −0.2<x<0.2, 0≤y<0.1, 0≤z<0.1, 0≤t≤0.5, 0≤2t/3, 0≤p≤t, 0≤q≤t/2, and k+½p+ 3/2q=t.

First claim

What is claimed is:

1 . A polyanionic compound, having the following chemical formula:
Na 2+x Mn 1−y M y Si 2−z M′ z O 6−t N k X p Y q   (1);
wherein, M is selected from Ni, Fe, Cu, Zn, Mg, Al, or a combination thereof; M′ is selected from Ge, Sn, Ti, or a combination thereof; X is selected from S, Se, or a combination thereof; and Y is selected from F, Cl, or a combination thereof;

wherein

-
0.2

<
x
<

0
.
2

,

0
≤
y
<

0
.
1

,

0
≤
z
<
0.1

,

0
≤
t
≤

0
.5

,

0
≤
k
≤

2
⁢
t
/
3

,

0
≤
p
≤
t

,

0
≤
q
≤

t
/
2

,

and
⁢

k

+

1
/
2
⁢
p

+

3
/
2
⁢
q

=

t
.

2 . The polyanionic compound according to claim 1 , wherein, −0.1≤x≤0, 0≤y≤0.08, and 0≤z≤0.05.

3 . The polyanionic compound according to claim 1 , wherein an X-ray powder diffraction pattern of the polyanionic compound has characteristic peaks at 2θ values of 34°±0.5°, 49°±0.5°, and 24°±0.5°.

4 . The polyanionic compound according to claim 1 , wherein an X-ray powder diffraction pattern of the polyanionic compound has a strongest characteristic diffraction peak attributed to a (222) crystal plane at a 2θ value of 34°±0.5°.

5 . The polyanionic compound according to claim 4 , wherein the polyanionic compound has an orthorhombic crystal structure belonging to a Pnnm space group.

6 . The polyanionic compound according to claim 5 , wherein the polyanionic compound has a unit cell parameter a meeting 7.5±1.5 Å, a unit cell parameter b meeting 10.5±1.5 Å, and a unit cell parameter c meeting 10.5±1.5 Å.

7 . The polyanionic compound according to claim 5 , wherein a unit cell of a crystal structure of the polyanionic compound comprises:
12 Na atoms, 6 Mn atoms, 12 Si silicon atoms, and 36 oxygen atoms; in the unit cell of the crystal structure of the polyanionic compound, the Mn atoms are at least partially substituted by an atom represented by M, the Si silicon atoms are at least partially substituted by an atom represented by M′, and the oxygen atoms are at least partially substituted by an atom represented by X.

8 . The polyanionic compound according to claim 7 , wherein
each Si atom forms a silicon-oxygen tetrahedron with four oxygen atoms at vertices, and every two silicon-oxygen tetrahedrons are corner-linked by sharing one oxygen atom; each Mn atom forms a manganese-oxygen octahedron with six oxygen atoms at vertices, and every two manganese-oxygen octahedrons are coplanar connected by sharing three oxygen atoms; the silicon-oxygen tetrahedron and the manganese-oxygen octahedron are corner-linked by sharing an oxygen atom.

9 . The polyanionic compound according to claim 8 , wherein the silicon-oxygen tetrahedrons and the manganese-oxygen octahedrons are corner-bridged into an anionic network by sharing an oxygen atom or X atom; and
Na + is arranged along an axis a of the crystal structure of the polyanionic compound and fills pores of the crystal structure.

10 . The polyanionic compound according to claim 1 , wherein the polyanionic compound satisfies at least one of following conditions:
(1) based on a total weight of the polyanionic compound, a mass percentage of element sodium contained in the polyanionic compound is 15% to 20%; or (2) in a crystal structure of the polyanionic compound, a disorder rate of any two types of atoms among Na atom, Mn atom, Si atom, and O atom is <3%.

11 . A secondary battery, comprising a positive electrode sheet, wherein the positive electrode sheet comprises a positive electrode current collector and a positive electrode material layer disposed on at least one side of the positive electrode current collector;
the positive electrode material layer comprises a positive electrode material; the positive electrode material comprises a polyanionic compound, having the following chemical formula:
Na 2+x Mn 1−y M y Si 2−z M′ z O 6−t N k X p Y q   (1); wherein,

M is selected from Ni, Fe, Cu, Zn, Mg, Al, or a combination thereof; M′ is selected from Ge, Sn, Ti, or a combination thereof; X is selected from S, Se, or a combination thereof; and Y is selected from F, Cl, or a combination thereof;

wherein

-
0.2

<
x
<

0
.
2

,

0
≤
y
<

0
.
1

,

0
≤
z
<
0.1

,

0
≤
t
≤

0
.5

,

0
≤
k
≤

2
⁢
t
/
3

,

0
≤
p

Assignees

• Ningde Amperex Technology Ltd

Inventors

• Zhou Molin
• Lu Yuhao
• Xu Leimin

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M4/131

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title