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CN-122025872-A - Lithium oxalate composite lithium supplementing agent, and preparation method and application thereof

CN122025872ACN 122025872 ACN122025872 ACN 122025872ACN-122025872-A

Abstract

The application belongs to the technical field of batteries, and particularly relates to a lithium oxalate composite lithium supplementing agent, a preparation method thereof, a positive plate, a battery and an electric device. The composite lithium supplementing agent comprises composite lithium supplementing agent particles, wherein the composite lithium supplementing agent particles comprise a lithium oxalate matrix and ion conductors, the ion conductors are distributed in the lithium oxalate matrix and are gradually decreased in concentration along the direction from the surface of the composite lithium supplementing agent particles to the center of the composite lithium supplementing agent particles. The composite lithium supplementing agent can obviously reduce the decomposition potential of lithium oxalate, so that the decomposition efficiency of lithium oxalate is obviously improved, and the lithium supplementing efficiency is improved.

Inventors

  • CAO MENGYAN
  • DONG ZIHAO
  • LING SHIGANG
  • LIU YAFEI
  • CHEN YANBIN

Assignees

  • 北京当升材料科技股份有限公司

Dates

Publication Date
20260512
Application Date
20260130

Claims (14)

  1. 1. The composite lithium supplementing agent is characterized by comprising composite lithium supplementing agent particles, wherein the composite lithium supplementing agent particles comprise a lithium oxalate matrix and ion conductors, the ion conductors are distributed in the lithium oxalate matrix and the concentration of the ion conductors is gradually decreased along the direction from the surface of the composite lithium supplementing agent particles to the center of the composite lithium supplementing agent particles.
  2. 2. The composite lithium supplement of claim 1, wherein the composite lithium supplement comprises the following compounds: Li 2 C 2 O 4 ·aLi x MO y Wherein Li x MO y represents the ion conductor, M represents at least one of Nb, ta, al, zr, ti, a is 0.08-0.19, x is 1 or 2, and y is 2 or 3.
  3. 3. The composite lithium-supplementing agent according to claim 2, wherein the concentration of M element is gradually decreased from P1 to P2 along the direction from the surface to the center of the composite lithium-supplementing agent particle, wherein the concentration of M element is the atomic percentage of the total content of C element, O element and M element; p1 is 2.4 at% -5.7 at%; P2 is 0.1 at% -0.3 at%.
  4. 4. The composite lithium supplement of claim 2, wherein the ionic conductor comprises at least one of LiNbO 3 、LiTaO 3 、LiAlO 2 、Li 2 ZrO 3 、Li 2 TiO 3 .
  5. 5. The composite lithium-supplementing agent according to claim 1, wherein in an XRD spectrum of the composite lithium-supplementing agent, a peak intensity ratio Q=I1/I2 of a peak intensity I1 of the first diffraction peak and a peak intensity I2 of the second diffraction peak satisfies that Q is 0.32≤Q≤1.75; wherein the first diffraction peak is the strongest diffraction peak of the ion conductor in the XRD spectrum, and the second diffraction peak is the diffraction peak at the position of 33.9+/-0.2 DEG of 2 theta in the XRD spectrum.
  6. 6. The composite lithium supplement of claim 5, wherein the 2Θ angle of the first diffraction peak is 23.5 ± 0.3 °, 23.6 ± 0.3 °, 22.3 ± 0.3 °, 42.3 ± 0.3 °, or 42.7 ± 0.3 °.
  7. 7. The composite lithium supplement of claim 1, wherein at least one of the following conditions is satisfied: the Dv50 of the composite lithium supplementing agent particles is 1-10 mu m, preferably 1-5 mu m; The specific surface area of the composite lithium supplement particles is 1m 2 /g~10 m 2 /g, preferably 1m 2 /g~5 m 2 /g.
  8. 8. A method of preparing the composite lithium-supplementing agent according to any one of claims 1 to 7, comprising: providing a lithium oxalate matrix; carrying out first mixing on the lithium oxalate matrix, a first lithium source and an M source in a first solvent to obtain a first mixture; Reacting and drying the first mixture to obtain a composite lithium supplementing agent precursor; calcining the precursor of the composite lithium supplementing agent for 12-24 hours at 300-350 ℃ in oxygen or air atmosphere to obtain the composite lithium supplementing agent.
  9. 9. The method of claim 8, wherein providing a lithium oxalate base comprises second mixing a second lithium source and an oxalic acid source in a second solvent to obtain a second mixture; And carrying out spray drying on the second mixture to obtain the lithium oxalate matrix.
  10. 10. The method of claim 9, wherein at least one of the following conditions is satisfied: The first lithium source and the second lithium source independently comprise at least one of lithium hydroxide and lithium hydroxide monohydrate; the oxalic acid source comprises at least one of oxalic acid and oxalic acid dihydrate; the M source comprises at least one of Nb(OC 2 H 5 ) 5 、Ta(OC 2 H 5 ) 5 、Al(OC 2 H 5 ) 3 、Zr(OC 2 H 5 ) 4 、Ti(OC 2 H 5 ) 4 、Nb(OCH(CH 3 ) 2 ) 5 、Ta(OCH(CH 3 ) 2 ) 5 、Al(OCH(CH 3 ) 2 ) 3 、Zr(OCH(CH 3 ) 2 ) 4 、Ti(OCH(CH 3 ) 2 ) 4 ; The first solvent comprises at least one of an ethanol solution with the volume fraction of 95-98%, a methanol solution with the volume fraction of 95-98% and an isopropanol solution with the volume fraction of 95-98%; The second solvent includes pure water.
  11. 11. The method of claim 10, wherein at least one of the following conditions is satisfied: the molar ratio of the second lithium source, the oxalic acid source and the M source is (1.95-2.05) 1 (0.08-0.19); the concentration of the first lithium source in the first mixture is from 0.1 mol/L to 1.0 mol/L, preferably from 0.2 mol/L to 0.4 mol/L.
  12. 12. A positive electrode sheet comprising the composite lithium supplementing agent according to any one of claims 1 to 7.
  13. 13. A battery comprising the composite lithium-supplementing agent according to any one of claims 1 to 7 or the positive electrode sheet according to claim 12.
  14. 14. An electrical device comprising the composite lithium-supplementing agent according to any one of claims 1 to 7, the positive electrode sheet according to claim 12, or the battery according to claim 13.

Description

Lithium oxalate composite lithium supplementing agent, and preparation method and application thereof Technical Field The application belongs to the technical field of batteries, and particularly relates to a lithium oxalate composite lithium supplementing agent, a preparation method and application thereof, and more particularly relates to a lithium oxalate composite lithium supplementing agent, a preparation method thereof, a positive plate, a battery and an electric device. Background Under existing battery systems, while the energy density of the battery can be improved by optimizing the battery structure or developing high specific volume electrode materials, there is still a significant loss of active lithium ions, which severely limits the energy density of the battery. At present, the sacrificial lithium supplement additive Li 2C2O4 has received a great deal of attention because of the advantages of good stability, low production cost, high theoretical specific capacity and the like. However, lithium oxalate materials are poor in conductivity, and their actual decomposition potential is typically higher than 4.7V, which severely limits their practical application. Accordingly, the related art of lithium supplements has yet to be improved. Disclosure of Invention The present application aims to solve at least one of the technical problems in the related art to some extent. Therefore, the application provides a lithium oxalate composite lithium supplementing agent with low decomposition potential and high lithium supplementing efficiency, and a preparation method and application thereof. In a first aspect of the present application, a composite lithium-supplementing agent is provided, including composite lithium-supplementing agent particles, the composite lithium-supplementing agent particles include a lithium oxalate matrix and ion conductors, the ion conductors are distributed in the lithium oxalate matrix, and the concentration of the ion conductors decreases along the direction from the surface of the composite lithium-supplementing agent particles to the center of the composite lithium-supplementing agent particles. According to the lithium oxalate composite ion conductor, a structure with specific ion conductor distribution is built in lithium oxalate, so that a continuous and sufficient lithium ion transmission channel can be formed, a lithium ion migration path is greatly widened, the ion conduction capacity of a lithium oxalate matrix is remarkably improved, and on the other hand, the composite ion conductor can be subjected to controllable decomposition synchronously in the first-week charging process, and the generated decomposition product can play a role in high-efficiency catalysis, so that the decomposition reaction process of the lithium oxalate is accelerated. The above effects are exerted cooperatively, so that the decomposition potential of the lithium oxalate lithium supplementing agent is effectively reduced, the overall decomposition efficiency of lithium oxalate is remarkably improved, and the overall lithium supplementing efficiency of the composite lithium supplementing agent particles is improved. According to an embodiment of the application, the following compounds are included: Li2C2O4·aLixMOy Wherein Li xMOy represents the ion conductor, M represents at least one of Nb, ta, al, zr, ti, a is 0.08-0.19, x is 1 or 2, and y is 2 or 3. According to the embodiment of the application, the concentration of M element is gradually reduced from P1 to P2 along the direction from the surface to the center of the composite lithium supplementing agent particle, wherein the concentration of M element is the atomic percent of the content of M element to the total content of C element, O element and M element; p1 is 2.4 at% -5.7 at%; P2 is 0.1 at% -0.3 at%. According to an embodiment of the application, the ion conductor comprises at least one of LiNbO 3、LiTaO3、LiAlO2、Li2ZrO3、Li2TiO3. According to the embodiment of the application, in the XRD spectrum of the composite lithium supplementing agent, the peak intensity ratio Q=I1/I2 of the peak intensity I1 of the first diffraction peak and the peak intensity I2 of the second diffraction peak is 0.32-1.75; wherein the first diffraction peak is the strongest diffraction peak of the ion conductor in the XRD spectrum, and the second diffraction peak is the diffraction peak at the position of 33.9+/-0.2 DEG of 2 theta in the XRD spectrum. According to an embodiment of the present application, the 2θ angles of the first diffraction peak are 23.5±0.3°, 23.6±0.3°, 22.3±0.3°, 42.3±0.3° or 42.7±0.3°. According to an embodiment of the present application, the above-described composite lithium supplementing agent satisfies at least one of the following conditions: The Dv50 of the composite lithium supplementing agent particles is 1-10 mu m, and specifically 1-5 mu m; The specific surface area of the composite lithium supplementing agent particles is 1 m