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EP-4742317-A1 - POSITIVE ELECTRODE ACTIVE MATERIAL AND PREPARATION METHOD THEREFOR, POSITIVE ELECTRODE SHEET, BATTERY, AND ELECTRICAL DEVICE

EP4742317A1EP 4742317 A1EP4742317 A1EP 4742317A1EP-4742317-A1

Abstract

The present application discloses a positive electrode active material and a preparation method thereof, a positive electrode plate, a battery, and an electric apparatus, where the positive electrode active material includes a sodium manganese oxide, the sodium manganese oxide includes a first phase and a second phase, the first phase includes alternating first sodium ion layers and first transition metal layers, and the second phase includes alternating second sodium ion layers and second transition metal layers. In the first phase, an interlayer spacing between adjacent first transition metal layers in a direction perpendicular to a (001) crystal plane is d 1 , in the second phase, an interlayer spacing between adjacent second transition metal layers in the direction perpendicular to the (001) crystal plane is d 2 , and d 1 -d 2 ranges from 0.01 nm to 0.02 nm.

Inventors

  • WU, KAI
  • LIANG, Zibin
  • WANG, Yuhao
  • LIN, Wenguang
  • LI, QIANG
  • ZHANG, XINXIN

Assignees

  • Contemporary Amperex Technology Co., Limited

Dates

Publication Date
20260513
Application Date
20231030

Claims (20)

  1. A positive electrode active material, comprising a sodium manganese oxide, wherein the sodium manganese oxide comprises a first phase and a second phase, the first phase comprising alternating first sodium ion layers and first transition metal layers, and the second phase comprising alternating second sodium ion layers and second transition metal layers; and in the first phase, an interlayer spacing between adjacent first transition metal layers in a direction perpendicular to a (001) crystal plane is d 1 , in the second phase, an interlayer spacing between adjacent second transition metal layers in the direction perpendicular to the (001) crystal plane is d 2 , and d 1 -d 2 ranges from 0.01 nm to 0.02 nm.
  2. The positive electrode active material according to claim 1, wherein the sodium manganese oxide comprises a doping element Q, the doping element satisfying at least one of the following conditions: the doping element Q comprises a first doping element Q1, the first doping element partially substituting sodium in the sodium manganese oxide, and the first doping element comprising at least one of Li, K, Ca, La, and Sr; the doping element Q comprises a second doping element Q2, the second doping element partially substituting manganese in the sodium manganese oxide, and the second doping element comprising at least one of Fe, Co, Ni, Cu, Zn, Ga, Li, B, Mg, Al, Si, Ti, Y, Zr, Nb, Mo, In, Sn, Sb, La, Ce, Ta, W, and Bi; and the doping element Q comprises a third doping element Q3, the third doping element partially substituting oxygen in the sodium manganese oxide, and the third doping element comprising at least one of F and Cl.
  3. The positive electrode active material according to claim 1 or 2, wherein the sodium manganese oxide satisfies a chemical formula: Na x Q1 a Mn y Q2 b O z Q3 c , wherein 0.5 < x ≤ 1.2 , 0 ≤ a ≤ 0.5 , and 0.5<x+a≤1.2; 0 < y , 0 ≤ b ≤ 0.6 , and y+b=1; and 1.8 ≤ z ≤ 2.2 , 0 ≤ c ≤ 0.2 , and 1.8≤z+c≤2.2.
  4. The positive electrode active material according to claim 3, wherein the sodium manganese oxide satisfies a chemical formula: Na x Q1 a Mn y Fe d Ni e Q2 b O z Q3 c , wherein y+d+e+b=1, 0.1≤d≤0.6, and 0.1≤e≤0.6; and in the first phase, a diffraction peak intensity of the first transition metal layer/the first sodium ion layer for X-rays within 2θ ranges from 13° to 16.2° is S 1 , and in the second phase, a diffraction peak intensity of the second transition metal layer/the second sodium ion layer for X-rays within 20 ranges from 16.2° to 17° is S 2 , wherein S 1 /(S 2 +S 1 )×e≤0.1.
  5. The positive electrode active material according to claim 4, wherein 0.05≤S 1 /(S 2 +S 1 ).
  6. The positive electrode active material according to any one of claims 1-5, wherein the first phase of the sodium manganese oxide satisfies a chemical formula: Na x1 Q1 a1 Mn y1 Fe d1 Ni e1 Q2 b1 O z Q3 c1 , wherein 0.6<x1≤0.8, 0≤a1≤0.6, 0≤b1≤0.6, y1+d1+e1+c1=1, and 0≤(d1×e1)/(y1 2 )≤0.5; and the second phase of the sodium manganese oxide satisfies a chemical formula: Na x2 Q1 a2 Mn y2 Fe d2 Ni e2 Q2 b2 O z Q3 c2 , wherein 0.7<x2≤1, 0.1≤a2≤0.6, 0.1≤b2≤0.6, y2+d2+e2+c2=1, and 0.1≤(d2×e2)/(y2 2 )≤1.
  7. The positive electrode active material according to claim 6, wherein in the first phase, the diffraction peak intensity of the first transition metal layer/the first sodium ion layer for X-rays within 2θ ranges from 13° to 16.2° is S 1 , in the second phase, the diffraction peak intensity of the second transition metal layer/the second sodium ion layer for X-rays within 20 ranges from 16.2° to 17° is S 2 , and S 1 and S 2 satisfy 0.01≤S 1 /(S 1 +S 2 )≤0.5.
  8. The positive electrode active material according to any one of claims 1-7, wherein 0.550 nm≤d 1 ≤0.565 nm, and 0.530 nm≤d 2 ≤0.545 nm.
  9. The positive electrode active material according to any one of claims 1-8, wherein the first phase is a P2 phase with a space group of P63/mmc; and the second phase is an O3 phase with a space group of R3m.
  10. The positive electrode active material according to any one of claims 1-9, wherein at 25°C, a pH of a deionized water solution of the positive electrode active material with a mass concentration of 2 g/18 mL is 7-13.
  11. A method for preparing the positive electrode active material according to any one of claims 1-10, comprising: providing a precursor; performing a calcination treatment on the precursor to obtain the positive electrode active material, wherein the positive electrode active material comprises a sodium manganese oxide; and the sodium manganese oxide comprises a first phase and a second phase, the first phase comprising alternating first sodium ion layers and first transition metal layers; the second phase comprising alternating second sodium ion layers and second transition metal layers; and in the first phase, an interlayer spacing between adjacent first transition metal layers in a direction perpendicular to a (001) crystal plane is d 1 , in the second phase, an interlayer spacing between adjacent second transition metal layers in the direction perpendicular to the (001) crystal plane is d 2 , and d 1 -d 2 ranges from 0.01 nm to 0.02 nm.
  12. The method according to claim 11, wherein the providing a precursor comprises: providing a mixture of a first sodium manganese oxide and a second sodium manganese oxide, wherein a molar amount of the first sodium manganese oxide in the mixture is m 1 , a molar amount of the second sodium manganese oxide in the mixture is m 2 , and m 1 :m 2 ranges from (1:2) to (1:10), wherein an interlayer spacing between adjacent first transition metal layers in the first sodium manganese oxide in the direction perpendicular to the (001) crystal plane is 0.550 nm-0.565 nm, and an interlayer spacing between adjacent second transition metal layers in the second sodium manganese oxide in the direction perpendicular to the (001) crystal plane is 0.530 nm-0.545 nm.
  13. The method according to claim 11 or 12, wherein the calcination treatment satisfies at least one of the following conditions: a temperature of the calcination treatment is 800°C-900°C; and a duration of the calcination treatment is 0.5 h-20 h.
  14. The method according to claim 12, wherein providing the first sodium manganese oxide comprises: providing a mixture of a sodium source, a manganese oxide, and a doping element oxide, and performing a first calcination treatment, wherein a molar amount of the sodium source in the mixture is m 1-1 , a molar amount of the manganese oxide in the mixture is m 2-1 , a molar amount of the doping element oxide in the mixture is m 3-1 , and m 1-1 :m 2-1 :m 3-1 =(0.5-0.8):(0.6-0.95):(0-0.4).
  15. The method according to claim 14, wherein the first calcination treatment satisfies at least one of the following conditions: a temperature of the first calcination treatment is 700°C-900°C; and a duration of the first calcination treatment is 10 h-20 h.
  16. The method according to claim 12, wherein providing the second sodium manganese oxide comprises: providing a mixture of a sodium source, a manganese oxide, and a doping element oxide, and performing a second calcination treatment, wherein a molar amount of the sodium source in the mixture is m 1-2 , a molar amount of the manganese oxide in the mixture is m 2-2 , a molar amount of the doping element oxide in the mixture is m 3-2 , and m 1-2 :m 2-2 :m 3-2 =(0.8-1.1):(0.3-0.5):(0-0.6).
  17. The method according to claim 16, wherein the second calcination treatment satisfies at least one of the following conditions: a temperature of the second calcination treatment is 800°C-1100°C; and a duration of the second calcination treatment is 10 h-20 h.
  18. A positive electrode plate, comprising the positive electrode active material according to any one of claims 1-10, and/or a positive electrode active material prepared using the method according to any one of claims 11-17.
  19. A battery, comprising the positive electrode plate according to claim 18.
  20. An electric apparatus, comprising the battery according to claim 19.

Description

TECHNICAL FIELD The present disclosure relates to the field of batteries, and specifically, to a positive electrode active material and a preparation method thereof, a positive electrode plate, a battery, and an electric apparatus. BACKGROUND Sodium-ion batteries are secondary batteries that primarily rely on the movement of sodium ions between positive and negative electrodes to function. Secondary batteries, represented by sodium-ion batteries, have been applied in various fields, such as energy storage power systems (for example, hydroelectric, thermal, wind, and solar power stations), electric vehicles, and aerospace. Compared to lithium-ion batteries, sodium salts, which are the main components of positive electrode active materials for sodium-ion batteries, are more abundant in reserves and significantly less expensive than lithium salts, which are the main components of positive electrode active materials for lithium-ion batteries, thereby providing sodium-ion batteries with a significant cost advantage in raw materials. However, sodium-ion batteries still face issues such as low energy density and poor stability, which limit their practical applications. SUMMARY According to a first aspect of the present application, a positive electrode active material is provided, where the positive electrode active material includes a sodium manganese oxide, the sodium manganese oxide includes a first phase and a second phase, the first phase includes alternating first sodium ion layers and first transition metal layers, and the second phase includes alternating second sodium ion layers and second transition metal layers; and in the first phase, an interlayer spacing between adjacent first transition metal layers in a direction perpendicular to a (001) crystal plane is d1, in the second phase, an interlayer spacing between adjacent second transition metal layers in the direction perpendicular to the (001) crystal plane is d2, and d1-d2 ranges from 0.01 nm to 0.02 nm. This configuration enables the first phase and the second phase to experience reduced strain during sodium insertion and extraction, thereby reducing defects and cracks in the crystal structure and enhancing the cycling stability of the positive electrode active material. According to an embodiment of the present application, the sodium manganese oxide includes a doping element Q, where the doping element satisfies at least one of the following conditions: the doping element Q includes a first doping element Q1, where the first doping element partially substitutes sodium in the sodium manganese oxide, and the first doping element includes at least one of Li, K, Ca, La, and Sr; and the doping element Q includes a second doping element Q2, where the second doping element partially substitutes manganese in the sodium manganese oxide, and the second doping element includes at least one of Fe, Co, Ni, Cu, Zn, Ga, Li, B, Mg, Al, Si, Ti, Y, Zr, Nb, Mo, In, Sn, Sb, La, Ce, Ta, W, and Bi; and the doping element Q includes a third doping element Q3, where the third doping element partially substitutes oxygen in the sodium manganese oxide, and the third doping element includes at least one of F and Cl. This configuration can further enhance the structural stability and specific capacity of the positive electrode active material. According to an embodiment of the present application, the sodium manganese oxide satisfies a chemical formula: NaxQ1aMnyQ2bOzQ3c, where 0.5<x≤1.2, 0≤a≤0.5, and 0.5<x+a≤1.2; 0<y, 0≤b≤0.6, and y+b=1; and 1.8≤z≤2.2, 0≤c≤0.2, and 1.8≤z+c≤2.2. This configuration can enhance the structural stability of the positive electrode active material during cycling. According to an embodiment of the present application, the sodium manganese oxide satisfies a chemical formula: NaxQ1aMnyFedNieQ2bOzQ3c, where y+d+e+b=1, 0.1≤d≤0.6, and 0.1≤e≤0.6; and in the first phase, a diffraction peak intensity of the first transition metal layer/the first sodium ion layer for X-rays within 2θ ranges from 13° to 16.2° is S1, and in the second phase, a diffraction peak intensity of the second transition metal layer/the second sodium ion layer for X-rays within 2θ ranges from 16.2° to 17° is S2, where S1/(S2+S1)×e≤0.1. This configuration can enhance the specific capacity, average discharge voltage, and structural stability of the positive electrode active material during cycling. According to an embodiment of the present application, 0.05≤S1/(S2+S1), optionally, 0.1≤S1/(S2+S1). This configuration can further enhance the structural stability and specific capacity of the positive electrode active material. According to an embodiment of the present application, the first phase of the sodium manganese oxide satisfies a chemical formula: Nax1Q1a1Mny1Fed1Nie1Q2b1OzQ3c1, where 0.6<x1≤0.8, 0≤a1≤0.6, 0≤b1≤0.6, y1+d1+e1+c1=1, and 0≤(d1×e1)/(y12)≤0.5; and the second phase of the sodium manganese oxide satisfies a chemical formula: Nax2Q1a2Mny2Fed2Nie2Q2b2OzQ3c2, where 0.7<x2≤1, 0.