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WO-2026090936-A1 - ELECTROCHEMICAL DEVICE AND ELECTRONIC DEVICE

WO2026090936A1WO 2026090936 A1WO2026090936 A1WO 2026090936A1WO-2026090936-A1

Abstract

The present application discloses an electrochemical device and an electronic device. The electrochemical device comprises a positive electrode sheet and a negative electrode sheet. The positive electrode sheet comprises a positive electrode material; the positive electrode material comprises a sodium element and a lithium element; and on the basis of the mass of the positive electrode sheet, the mass ratio of the sodium element ranges from 0.2% to 3%. The negative electrode sheet comprises a negative electrode material; the negative electrode material comprises a sodium element; and on the basis of the mass of the negative electrode sheet, the mass ratio of the sodium element ranges from 0.05% to 1.2%. The electrochemical device of the present application has good low-temperature cycle performance and kinetic performance.

Inventors

  • LI, GAOFENG
  • XU, LEIMIN
  • ZHANG, HUI
  • YE, Zeqing

Assignees

  • 宁德新能源科技有限公司

Dates

Publication Date
20260507
Application Date
20241030

Claims (10)

  1. An electrochemical device includes a positive electrode and a negative electrode, characterized in that the positive electrode includes a positive electrode material, the positive electrode material includes sodium and lithium elements, and the mass percentage of sodium elements is 0.2% to 3% based on the mass of the positive electrode. The negative electrode sheet includes a negative electrode material, which includes sodium. Based on the mass of the negative electrode sheet, the mass percentage of sodium is between 0.05% and 1.2%.
  2. The electrochemical device as claimed in claim 1, wherein the positive electrode material further comprises boron, and the mass percentage of boron is 0.01% to 0.3% based on the mass of the positive electrode sheet.
  3. The electrochemical device according to claim 1 is characterized in that, based on the mass of the positive electrode, the mass percentage of sodium is A%, the mass percentage of lithium is B%, and the B/A ratio is 1.83 to 40.
  4. The electrochemical device according to claim 1 is characterized in that, based on the mass of the positive electrode, the mass percentage of lithium is 5.5% to 8%.
  5. The electrochemical device according to any one of claims 1 to 4, characterized in that the positive electrode material further comprises manganese, wherein the mass percentage of manganese is 24.43% to 30% based on the mass of the positive electrode sheet; and/or The positive electrode material also includes nickel, and the mass percentage of nickel is 26.2% to 32% based on the mass of the positive electrode sheet.
  6. The electrochemical device according to any one of claims 1 to 4 is characterized in that the negative electrode material comprises graphite or silicon-based material.
  7. The electrochemical device according to any one of claims 1 to 4 is characterized in that the negative electrode material satisfies at least one of the following characteristics: (1) The negative electrode material further includes boron, and the mass percentage of boron is 0.02% to 0.1% based on the mass of the negative electrode sheet; (2) Based on the mass of the negative electrode sheet, the mass percentage of sodium element is 0.5% to 1.2%.
  8. The electrochemical device according to any one of claims 1 to 4 is characterized in that the negative electrode material satisfies at least one of the following characteristics: (1) The negative electrode material also includes manganese, and the mass percentage of manganese is 0.001% to 0.04% based on the mass of the negative electrode sheet; (2) The negative electrode material also includes nickel, and the mass percentage of nickel is 0.002% to 0.02% based on the mass of the negative electrode sheet; (3) Based on the mass of the negative electrode sheet, the mass percentage of sodium element is 0.07% to 0.4%.
  9. The electrochemical device according to any one of claims 1 to 4 is characterized in that it further comprises an electrolyte, said electrolyte comprising adiponitrile, fluoroethylene carbonate and vinylene carbonate.
  10. An electronic device, characterized in that it includes an electrochemical device as described in any one of claims 1 to 9.

Description

Electrochemical devices and electronic devices Technical Field This application relates to the field of electrochemistry, and more particularly to an electrochemical device and an electronic device. Background Technology Lithium-ion batteries are currently widely used in consumer electronics, electric vehicles, and aerospace. Low-temperature performance and rate performance are key factors affecting battery applications. However, traditional lithium-ion batteries are prone to capacity decay, increased internal resistance, low efficiency, and high heat generation in low-temperature environments. To address these issues, extensive research has been conducted at the positive and negative electrode material levels. For positive electrode materials, multivalent metal ion doping is employed to enhance conductivity and ion mobility, thereby improving battery performance. For negative electrode materials, a protective layer is coated onto the material surface to improve interfacial stability and suppress side reactions. However, these methods still face many challenges, such as insufficient uniformity of doped elements, limited coating stability, and complex fabrication processes. Summary of the Invention In view of this, this application provides an electrochemical device and an electronic device. The first aspect of this application provides an electrochemical device, including a positive electrode and a negative electrode. The positive electrode includes a positive electrode material, which includes sodium and lithium elements, and the sodium element accounts for 0.2% to 3% of the total mass based on the mass of the positive electrode. The negative electrode includes a negative electrode material, which includes sodium elements, and the sodium element accounts for 0.05% to 1.2% of the total mass based on the mass of the negative electrode. This application incorporates sodium into the cathode material. Since sodium ions have a larger radius than lithium ions, when sodium ions enter the lithium layer, they increase the interlayer spacing, which is beneficial for lithium ion diffusion and improves… The diffusion kinetics of lithium ions in the cathode material are improved, enabling the electrochemical device to have good low-temperature cycling performance and kinetic performance (such as charge-discharge rate). This application adds sodium to the negative electrode material, which undergoes reversible dissolution and deposition during the charge and discharge process of the electrochemical device, providing additional capacity to the electrochemical device. Sodium can also form more inorganic components on the surface of the negative electrode material, making the SEI film denser and more uniform, and improving the stability of the negative electrode material surface. Due to the presence of sodium, the desolvation process of lithium ions on the surface of the negative electrode material can be promoted, especially the desolvation capability at low temperature, thereby improving the low-temperature cycling performance and kinetic performance of the electrochemical device. Based on the first aspect, in some possible implementations, the positive electrode material also includes boron, with the boron content ranging from 0.01% to 0.3% based on the mass of the positive electrode sheet. This application adds boron to the cathode material and controls the mass ratio of boron to meet the above-mentioned range. Since boron forms on the surface of the cathode material, it reduces the side reactions between the cathode material and the electrolyte, improves the stability of the cathode material surface, and further enhances the low-temperature cycling performance of the electrochemical device. Based on the first aspect, in some possible implementations, when the positive electrode is in a fully discharged state, the mass percentage of sodium is A% and the mass percentage of lithium is B%, based on the mass of the positive electrode, and the B/A ratio is 1.83 to 40. This application further improves the low-temperature cycling performance and kinetic performance of the electrochemical device by controlling the mass ratio of lithium and sodium elements in the cathode material to meet the above-mentioned range. Based on the first aspect, in some possible implementations, when the positive electrode is in a fully discharged state, the positive electrode material also includes lithium, and the mass percentage of lithium is 5.5% to 8% based on the mass of the positive electrode. This application improves the low-temperature cycling performance and kinetic performance of the electrochemical device by controlling the mass ratio of lithium in the cathode material to meet the above range. Based on the first aspect, in some possible implementations, when the positive electrode is in a fully discharged state, the positive electrode material also includes manganese, and the mass percentage of manganese is 24.43% to [missing informatio