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US-12626915-B2 - Sodium-ion battery, positive electrode plate for sodium-ion battery, positive active material, battery module, battery pack, and device

US12626915B2US 12626915 B2US12626915 B2US 12626915B2US-12626915-B2

Abstract

This application relates to a sodium-ion battery, a positive electrode plate for a sodium-ion battery, a battery module, a battery pack, and a device. The sodium-ion battery according to this application includes a positive electrode plate, a negative electrode plate, a separator, and an electrolytic solution. The positive electrode plate includes a positive active material. A molecular formula of the positive active material satisfies Na a Li b M 0.7 Fe 0.3−b O 2±δ , M is a transition metal ion, 0.67<a<1.1, 0<b<0.3, 0≤δ≤0.1, and a ratio of R ct to R f of the positive active material satisfies 1.0<R ct /R f <20.0. R ct is a charge transfer resistance of the positive active material measured in a button battery based on alternating current impedance spectroscopy, and R f is a diffusion resistance of the positive active material measured in the button battery based on the alternating current impedance spectroscopy.

Inventors

  • Liting Huang
  • Yongsheng Guo
  • Chengdu Liang
  • Jiadian Lan
  • Wenguang Lin

Assignees

  • CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED

Dates

Publication Date
20260512
Application Date
20211222
Priority Date
20191018

Claims (15)

  1. 1 . A sodium-ion battery, comprising a positive electrode plate, a negative electrode plate, a separator, and an electrolytic solution, wherein the positive electrode plate comprises a positive active material, a molecular formula of the positive active material satisfies Na a Li b M 0.7 Fe 0.3−b O 2±δ , M is a combination of Mn and one of Cu, Zn, and Mg, 0.67<a<1.1, 0.05<b<0.2, 0<δ<0.1, and in a charge and discharge curve of a button battery made of the positive active material, a ratio of R ct to R f of the positive active material satisfies 2<R ct /R f <3 for the first cycle and 4.29≤R ct /R f ≤6.72 for the 100 th cycle; R ct is a charge transfer resistance of the positive active material measured in the button battery based on alternating current impedance spectroscopy; and R f is a diffusion resistance of the positive active material measured in the button battery based on the alternating current impedance spectroscopy, a median diameter D v 50 of the positive active material (μm), a specific surface area S (m 2 /g) of the positive active material, and the R ct /R f satisfy: 47.5 < R ct / R f * D v ⁢ 5 ⁢ 0 S < 160.
  2. 2 . The sodium-ion battery according to claim 1 , wherein a resistance of the positive electrode plate is R≤1,000 mΩ.
  3. 3 . The sodium-ion battery according to claim 1 , wherein a resistance of the positive electrode plate is R≤100 mΩ.
  4. 4 . The sodium-ion battery according to claim 1 , wherein a tapped density of the positive active material is greater than 1 g/cm 3 .
  5. 5 . The sodium-ion battery according to claim 1 , wherein a tapped density of the positive active material is within a range of 1.5˜3 g/cm 3 .
  6. 6 . The sodium-ion battery according to claim 1 , wherein a compacted density of the positive active material under 8 tons is within a range of 1.5˜4.5 g/cm 3 .
  7. 7 . The sodium-ion battery according to claim 1 , wherein a median diameter D v 50 of the positive active material is within a range of 0.05˜50 μm.
  8. 8 . The sodium-ion battery according to claim 1 , wherein a median diameter D v 50 of the positive active material is within a range of 3˜30 μm.
  9. 9 . The sodium-ion battery according to claim 1 , wherein a specific surface area S of the positive active material is within a range of 0.01˜30 m 2 /g.
  10. 10 . The sodium-ion battery according to claim 1 , wherein a specific surface area S of the positive active material is within a range of 0.1˜10 m 2 /g.
  11. 11 . The sodium-ion battery according to claim 1 , wherein the negative active material in the negative electrode plate is a carbon material.
  12. 12 . The sodium-ion battery according to claim 1 , wherein the negative active material in the negative electrode plate is a hard carbon material.
  13. 13 . The sodium-ion battery according to claim 1 , wherein an areal density A (g/m 2 ) of a single-sided positive active material layer of the positive electrode plate and an areal density B (g/m 2 ) of a single-sided negative active material layer of the negative electrode plate satisfy: 1.8<A/B<2.57.
  14. 14 . A device that uses a sodium-ion battery as a power supply, wherein the device comprises the sodium-ion battery according to claim 1 .
  15. 15 . A positive active material for a sodium-ion battery, wherein a molecular formula of the positive active material satisfies Na a Li b M 0.7 Fe 0.3−b O 2±δ , M is a combination of Mn and one of Cu, Zn, and Mg, 0.67<a<1.1, 0.05<b<0.2, and 0≤δ≤0.1, and in a charge and discharge curve of a button battery made of the positive active material, a ratio of R ct to R f of the positive active material satisfies 2<R ct /R f <3 for the first cycle and 4.29≤R ct /R f ≤6.72 for the 100 th cycle, wherein, R ct is a charge transfer resistance of the positive active material measured in the button battery based on alternating current impedance spectroscopy; and R f is a diffusion resistance of the positive active material measured in the button battery based on the alternating current impedance spectroscopy, a median diameter D v 50 of the positive active material (μm), a specific surface area S (m 2 /g) of the positive active material, and the R ct /R f satisfy: 47.5 < R ct / R f * D v ⁢ 5 ⁢ 0 S < 160.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of International Patent Application No. PCT/CN2020/120314 filed on Oct. 12, 2020, which claims priority to Chinese Patent Application No. 201910995176.8, filed on Oct. 18, 2019. The aforementioned patent applications are incorporated herein by reference in their entirety. TECHNICAL FIELD This application relates to the field of batteries, and in particular, to a sodium-ion battery, a positive electrode plate for a sodium-ion battery, a battery module, a battery pack, and a device. BACKGROUND Currently, the lithium-ion battery technology is in a dominant position in the market of mainstream consumer batteries and power batteries. In the nearly three decades since its commercialization, the lithium-ion battery technology has matured gradually. Although bringing more and more convenience to mankind, lithium-ion batteries are facing great challenges. Lithium resources are increasingly scarce, the price of upstream materials keeps rising, the development of a recycling technology is lagging, and the recycling rate of old batteries is low. All such factors give rise to increasing market demand for a more economical and more efficient alternative technology. Sodium and lithium have similar physical and chemical properties. However, sodium is much more abundant in resource reserve than lithium, much more cost-efficient than lithium, and more widespread than lithium. As a new generation of electrochemical system that possibly replaces the existing energy storage technology, sodium-ion rechargeable batteries have attracted great attention from the scientific research circle and the industry circle in recent years. In the 1970s, researchers began to pay attention to the sodium-ion rechargeable battery technology, However, due to successful commercialization of lithium-ion batteries, the development of sodium batteries has been suspended for a long time. Since 2010, the lithium-ion battery technology has encountered challenges in terms of a high energy density requirement, cost-efficiency, performance, and safety, and the sodium-ion rechargeable battery technology has once again stepped into the spotlight of research in the battery field. In the aspects ranging from the research on positive and negative electrode materials as well as the development of an electrolytic solution and a separator to the design of a new chemical or electrochemical system, the sodium-ion rechargeable battery technology is evolving explosively. Similar to the case of a lithium-ion battery, the performance of a sodium-ion battery is primarily bottlenecked by a positive electrode material. Therefore, the development of a high-performance positive electrode material is critical to the application of the sodium ion battery. SUMMARY In view of the problems in the background technologies, an objective of this application is to provide a positive active material for a sodium-ion battery, a positive electrode plate containing the positive active material according to this application, a sodium-ion battery containing the positive electrode plate according to this application, a battery module, a battery pack, and a device. A ratio of Rct to Rf of the positive active material satisfies 1.0<Rct/Rf<20.0, where Rct is a charge transfer resistance, and Rf is a diffusion resistance. This ratio value can effectively improve sodium deintercalation performance of the positive electrode plate and effectively improve electrochemical performance of the sodium-ion battery. To fulfil the foregoing objective, according to a first aspect of this application, this application provides a sodium-ion battery, including a positive electrode plate, a negative electrode plate, a separator, and an electrolytic solution. The positive electrode plate includes a positive active material. A molecular formula of the positive active material satisfies NaaLibM0.7Fe0.3−bO2±δ, M is a transition metal ion, 0.67<a<1.1, 0<b<0.3, 0≤δ≤0.1, and a ratio of Rct to Rf of the positive active material satisfies 1.0<Rct/Rf<20.0. Rct is a charge transfer resistance of the positive active material measured in a button battery based on alternating current impedance spectroscopy. Rf is a diffusion resistance of the positive active material measured in the button battery based on the alternating current impedance spectroscopy. According to a second aspect of this application, this application provides a positive electrode plate for a sodium-ion battery. The positive electrode plate includes a positive active material layer carried on at least one surface of a positive current collector. The positive active material layer includes a positive active material. A molecular formula of the positive active material satisfies NaaLibM0.7Fe0.3−bO2±δ, M is a transition metal ion, 0.67<a<1.1, 0<b<0.3, 0<δ<0.1, and a ratio of Rct to Rf of the positive active material satisfies 1.0<Rct/Rf<20.0. Rct is a charge transfer resistance of the pos