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US-20260128302-A1 - CATHODE ACTIVE MATERIAL AND PREPARATION METHOD THEREOF, POSITIVE ELECTRODE PLATE, BATTERY, AND ELECTRICAL DEVICE

US20260128302A1US 20260128302 A1US20260128302 A1US 20260128302A1US-20260128302-A1

Abstract

Provided are a cathode active material and a preparation method thereof, a positive electrode plate, a battery, and an electrical device. The present disclosure relates to the technical field of batteries. A change An in a content of Fe 2+ in the cathode active material satisfies Δn≥0.1 and Δn=n1−n2; n1 is a content of Fe 2+ in the cathode active material prior to charging, and n2 is a content of Fe 2+ in the cathode active material when charging to 4.0 V; and the content of Fe 2+ =amount of Fe 2+ substance in the cathode active material/(the amount of Fe 2+ substance in the cathode active material+amount of Fe 3+ substance in the cathode active material). Therefore, by using the cathode active material, a battery loaded with the cathode active material can have excellent energy density.

Inventors

  • Feijiang Chen
  • Yafei Liu
  • Yanbin Chen

Assignees

  • BEIJING EASPRING MATERIAL TECHNOLOGY CO., LTD.

Dates

Publication Date
20260507
Application Date
20251230
Priority Date
20240628

Claims (20)

  1. 1 . A cathode active material, wherein a change Δn in a content of Fe 2 in the cathode active material satisfies Δn≥0.1 and Δn=n1−n2, where: n1 is a content of Fe 2+ in the cathode active material prior to charging; n2 is a content of Fe 2+ in the cathode active material when charging to 4.0 V; and the content of Fe 2+ =amount of Fe 2+ substance in the cathode active material/(amount of Fe 2+ substance in the cathode active material+amount of Fe 3+ substance in the cathode active material), and wherein the cathode active material comprises Na a1 Ni x1 Fe y1 Mn z1 Zn m1 Ca n1 M p1 O 2 , where: 0.9 ≤ a ⁢ 1 ≤ 1.1 ; 0 < x ⁢ 1 ≤ 0.5 ; 0 < y ⁢ 1 ≤ 0.5 ; 0 < z ⁢ 1 ≤ 0.5 ; 0 < m ⁢ 1 ≤ 0.1 ; 0 ≤ n ⁢ 1 ≤ 0 .05 ; 0 < p ⁢ 1 ≤ 0 .05 ; M comprises at least one of Cu, Ti, Mg, Sr, Sn, Sb, Zr, Nb, Y, W, or La; and a ⁢ 1 : ( x ⁢ 1 + y ⁢ 1 + z ⁢ 1 + m ⁢ 1 + n ⁢ 1 + p ⁢ 1 ) = ( 0.95 to 1.05 ) : 1.
  2. 2 . The cathode active material according to claim 1 , wherein Δn≥0.15.
  3. 3 . The cathode active material according to claim 1 , wherein n1 is greater than 50%.
  4. 4 . The cathode active material according to claim 1 , wherein: a ⁢ 1 : ( x ⁢ 1 + y ⁢ 1 + z ⁢ 1 + m ⁢ 1 + n ⁢ 1 + p ⁢ 1 ) = ( 0.95 to 1.05 ) : 1. 0.01 < m ⁢ 1 ≤ 0.1 ; and 0.01 < n ⁢ 1 ≤ 0.05 .
  5. 5 . The cathode active material according to claim 1 , wherein M has an ionic radius r(M) satisfying r(M)>0.06 nm.
  6. 6 . The cathode active material according to claim 1 , wherein the cathode active material is an O3-type sodium-ion battery layered oxide.
  7. 7 . The cathode active material according to claim 1 , wherein the cathode active material has a particle size D 50 ranging from 3 μm to 12 μm.
  8. 8 . The cathode active material according to claim 1 , wherein the cathode active material has a particle size distribution satisfying 1.1<(D 90 −D 10 )/D 50 <1.6.
  9. 9 . A method for preparing the cathode active material according to of claim 1 , the method comprising: evenly mixing a Na source, a cathode active material precursor, a Zn source, a Ca source, and an M source according to a stoichiometric ratio, to obtain a mixed material, wherein the cathode active material precursor comprises Fe; and calcining the mixed material in an oxidizing atmosphere, crushing and sieving the mixed material, to obtain the cathode active material, wherein said calcining comprises a first temperature-rising stage, a second temperature-rising stage, and a temperature-holding stage, and a difference between a rate of temperature rise in the first temperature-rising stage and a rate of temperature rise in the second temperature-rising stage ranges from 1° C./min to 10° C./min.
  10. 10 . The method according to claim 9 , wherein a ratio of amount of Na substance to a sum of amounts of Ni, Fe, Mn, Zn, Ca, and M substance ranges from 0.90 to 1.10.
  11. 11 . The method according to claim 9 , wherein a temperature of said calcining ranges from 900° C. to 1100° C.
  12. 12 . The method according to claim 9 , wherein said calcining comprises: the first temperature-rising stage: rising to a temperature T1 at a rate of temperature rise greater than or equal to 3° C./min; the second temperature-rising stage: rising to a temperature T2 at a rate of temperature rise smaller than or equal to 2° C./min; and the temperature-holding stage: holding a temperature range between T2−10° C. and T2+10° C. for a duration of t1, where: 600° C.≤T1≤800° C., 900° C.≤T2≤1100° C., and 5 hours≤t1≤15 hours.
  13. 13 . The method according to claim 9 , wherein the cathode active material precursor comprises: Ni x2 Fe y2 Mn z2 Zn m2 O a H b , where: 0 < x ⁢ 2 ≤ 0 . 5 , 0 < y ⁢ 2 ≤ 0 . 5 , 0 < z ⁢ 2 ≤ 0 . 5 , 0 ≤ m ⁢ 2 ≤ 0 .2 , 1 ≤ a ≤ 2 , 0 ≤ b ≤ 2 , and ⁢ x ⁢ 2 + y ⁢ 2 + z ⁢ 2 + m ⁢ 2 = 1 .
  14. 14 . The method according to claim 9 , wherein the cathode active material precursor has a particle size D 50 ranging from 5 μm to 6 μm.
  15. 15 . The method according to claim 9 , wherein the cathode active material precursor has a particle size distribution satisfying 1.1<(D 90 −D 10 )/D 50 <1.6.
  16. 16 . The method according to claim 9 , wherein the cathode active material precursor has a tap density ranging from 1.50 g/cm 3 to 1.80 g/cm 3 .
  17. 17 . The method according to claim 9 , wherein the cathode active material precursor has a specific surface area ranging from 10 m 2 /g to 20 m 2 /g.
  18. 18 . A positive electrode plate, comprising the cathode active material according to of claim 1 .
  19. 19 . A battery, comprising the positive electrode plate according to claim 18 .
  20. 20 . An electrical device, comprising the battery according to claim 19 .

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a continuation of International Application No. PCT/CN2024/109047, filed on Jul. 31, 2024, which claims priority and benefits of Chinese Patent Application No. 202410869502.1 filed with the China National Intellectual Property Administration on Jun. 28, 2024. The disclosures of the aforementioned applications are herein incorporated by reference in their entireties. FIELD The present disclosure relates to the field of batteries, and more particularly, to a cathode active material and a preparation method thereof, a positive electrode plate, a battery, and an electrical device. BACKGROUND In recent years, lithium-ion batteries have developed rapidly and are widely used in new energy vehicles, energy storage power stations, and digital 3C products. However, the price of lithium resources fluctuates greatly with market conditions. In the current industry background, sodium-ion batteries, due to the abundant and low-priced sodium resources thereof and the same working mechanism as lithium-ion batteries, can significantly reduce manufacturing cost of the batteries and are expected to be widely used in the field of low-speed electric vehicles and energy storage. In the sodium-ion battery system, cathode materials are mainly divided into three types: layered oxides, polyanions, and Prussian blue. The layered oxide (NaxMO2) materials, by virtue of the advantages thereof, such as high energy density, good low-temperature performance, simple process and suitability for large-scale production, have been first used in the markets of mid-end and low-end passenger cars, energy storage systems, etc. However, as the price of lithium falls, NaxMO2 materials are gradually losing the cost advantage, and there is an urgent need to further improve energy density and reduce material watt-hour cost. Therefore, how to solve the shortcomings of the above-mentioned NaxMO2 materials and improve the energy density of the material has become the subject to be studied and solved by the present disclosure. SUMMARY The present disclosure aims to solve, at least to a certain extent, one of the technical problems in the related art. To this end, an object of the present disclosure is to provide a cathode active material and a preparation method thereof, a positive electrode plate, a battery, and an electrical device. The cathode active material has a high capacity, which allows a battery containing the cathode active material to have an excellent energy density. In one aspect of the present disclosure, the present disclosure provides a cathode active material. A change An in a content of Fe2+ in the cathode active material satisfies Δn≥0.1 and Δn=n1−n2. n1 is a content of Fe2+ in the cathode active material prior to charging; n2 is a content of Fe2+ in the cathode active material when charging to 4.0 V; and the content of Fe2+=amount of Fe2+ substance in the cathode active material/(amount of Fe2+ substance in the cathode active material+amount of Fe3+ substance in the cathode active material). According to the cathode active material of the embodiment of the present disclosure, during the process of charging to 4.0 V, the change An in the content of Fe2+ satisfies Δn≥0.1, which causes more Fe2+ to be converted into Fe3+. The large change in the content of Fe2+ allows more electrons to be transferred during the charge process, thereby increasing the capacity of the cathode active material, and further improving the energy density of the battery containing the cathode active material. In addition, the cathode active material according to the above embodiment of the present disclosure may also have the following additional technical features. In some embodiments of the present disclosure, Δn≥0.15. In some embodiments of the present disclosure, n1 is greater than 50%; preferably, n1 is greater than 70%; and further preferably, n1 is greater than 80%. In some embodiments of the present disclosure, the cathode active material includes Naa1Nix1Fey1Mnz1Znm1Can1Mp1O2. 0.90≤a1≤1.10, 0≤x≤0.5, 0≤y1≤0.5, 0≤z1≤0.5, 0<m1≤0.2, 0≤n1≤0.05, and 0≤p1≤0.05; and M includes at least one of Cu, Ti, Mg, Sr, Sn, Sb, Zn, Zr, Nb, Y, W, or La. In some embodiments of the present disclosure, a1:(x1+y1+z1+m1+n1+p1)=(0.90 to 1.05):1, preferably, (0.95 to 1.05):1; and further preferably, (0.97 to 1.03):1. In some embodiments of the present disclosure, 0.01<m1≤0.2, and preferably, 0.05<m1≤0.1. In some embodiments of the present disclosure, 0.01<n1≤0.05. In some embodiments of the present disclosure, M has an ionic radius r(M) satisfying r(M)>0.06 nm. In some embodiments of the present disclosure, the cathode active material is an O3-type sodium-ion battery layered oxide. In some embodiments of the present disclosure, the cathode active material has a particle size D50 ranging from 3 μm to 12 μm, preferably, from 4 μm to 10 μm, and further preferably, from 5 μm to 8 μm. In some embodiments of the present disc