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CN-122000344-A - Ternary positive electrode material, preparation method thereof and lithium ion battery

CN122000344ACN 122000344 ACN122000344 ACN 122000344ACN-122000344-A

Abstract

The invention discloses a ternary positive electrode material, a preparation method thereof and a lithium ion battery. The general formula of the ternary positive electrode material is LiNi x Co y Mn z M 1‑x‑y‑z O 2 , X is more than or equal to 0.6 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 0.2, z is more than or equal to 0 and less than or equal to 0.2, M is a doping element, and M is one or more than one of Nb, W, ta, ti, hf, mo, la, ce, zr, and the ternary positive electrode material is tested by an X-ray energy spectrometer EDS, wherein the molar percentage of M tested under 10keV energy is recorded as P1, the molar percentage of M tested under 20keV energy is recorded as P2, and the ternary positive electrode material meets the requirement of 0.2< P2/P1<0.9. The invention realizes the transition metal ion doping of the surface layer depth of the ternary material, and in the circulation process, the deeply doped ions play a stronger role of 'rivets' on the structure, so that the structural stability of long-term circulation can be realized.

Inventors

  • LIU XIANCHUN
  • LIU XING
  • GAO WEI

Assignees

  • 合肥国轩高科动力能源有限公司

Dates

Publication Date
20260508
Application Date
20260120

Claims (10)

  1. 1. A ternary positive electrode material is characterized by having a general formula of LiNi x Co y Mn z M 1-x-y-z O 2 , X is more than or equal to 0.6 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 0.2, z is more than or equal to 0 and less than or equal to 0.2, M is a doping element, and M is one or more than one of Nb, W, ta, ti, hf, mo, la, ce, zr, wherein the ternary positive electrode material is tested by an X-ray energy spectrometer EDS, the molar percentage of M tested at 10keV energy is recorded as P1, the molar percentage of M tested at 20keV energy is recorded as P2, and the ternary positive electrode material meets 0.2< P2/P1<0.9.
  2. 2. The ternary cathode material according to claim 1, wherein the ternary cathode material P2 has a value ranging from 0.1% to 2%.
  3. 3. The method for preparing the ternary cathode material according to claim 1 or 2, comprising the following steps: S1, mixing a nickel-cobalt-manganese ternary precursor and lithium salt according to a molar ratio of 1 (0.8-0.98), and sintering at 870-1000 ℃ in pure oxygen atmosphere to obtain an ordered superlattice intermediate; S2, mixing the ordered superlattice intermediate with the rest lithium salt, a doping agent containing transition metal M and a layer-expanding agent, and sintering in pure oxygen atmosphere to obtain a ternary anode material with the M surface layer deeply doped and containing an ordered superlattice structure; wherein the molar ratio of the ordered superlattice intermediate to the residual lithium salt is 1 (0.12-0.32).
  4. 4. The method for preparing the ternary positive electrode material according to claim 3, wherein the structural general formula of the nickel-cobalt-manganese ternary precursor is [ Nix 1 Coy 1 Mnz 1 ](OH) 2 ], wherein x 1 ＜1,0＜y 1 ≤0.2,0＜z 1 is more than or equal to 0.6 and less than or equal to 0.2; and/or the lithium salt is selected from one or more of lithium hydroxide, lithium carbonate and lithium nitrate; And/or, in the step S1, the sintering heat preservation time is 3-8 hours.
  5. 5. The method of manufacturing a ternary cathode material according to claim 3, wherein the dopant is an oxide of the transition metal M.
  6. 6. The method for preparing a ternary positive electrode material according to claim 5, wherein the mass percentage of the dopant is 0.1% -1% based on the ordered superlattice intermediate.
  7. 7. The method for producing a ternary positive electrode material according to claim 3, wherein the expander is capable of providing a metal ion having an ionic radius greater than Li + , preferably Na + , and more preferably one or more of Na 2 CO 3 、NaOH、CH 3 COONa、Na 2 SO 4 .
  8. 8. The method for preparing a ternary positive electrode material according to claim 7, wherein the mass percentage of the layer-expanding agent is 0.3% -1% based on the ordered superlattice intermediate.
  9. 9. The method for preparing the ternary cathode material according to claim 3, wherein the sintering temperature in the step S2 is 650-820 ℃ and the heat preservation time is 10-15 h.
  10. 10. A lithium ion battery comprising the ternary cathode material of claim 1 or 2 or the ternary cathode material prepared by the method of any one of claims 3-9.

Description

Ternary positive electrode material, preparation method thereof and lithium ion battery Technical Field The invention belongs to the technical field of lithium ion battery material preparation, and particularly relates to a ternary positive electrode material, a preparation method thereof and a lithium ion battery. Background Lithium Ion Battery (LIB) technology is a key component of today's energy infrastructure, which further evolves towards higher energy density, longer cycle life, better safety and lower cost, critical for emerging applications such as utility-scale energy storage and unmanned aerial vehicles, while ternary positive electrode materials (NCM) are a major part of the mainstream technological route in positive electrode system competition by virtue of their comprehensive performance advantages. In the preparation process of NCM materials, in order to optimize the first week coulomb efficiency and alleviate the lithium loss problem in the cycling process, the traditional sintering scheme generally adopts a high lithium distribution strategy, namely, the excessive supplement of lithium is realized in the high-temperature solid-phase reaction by setting the lithium proportioning coefficient of 1.01-1.1. However, in the sintering process of high-lithium-content, lithium ions are preferentially ordered, so that the energy barrier for the diffusion of subsequent doping elements (such as Ti, mg, zr and the like) into the crystal lattice is remarkably increased, and a phenomenon of shallow surface doping is formed. The non-uniform doping can only generate a limited positive effect within the range of a few nanometers on the surface of the material, and cannot go deep into the interior of a crystal lattice to construct long-acting stable structural modification, so that the improvement space of the cycling stability of the material is limited. Disclosure of Invention The invention aims to provide a ternary positive electrode material, a preparation method thereof and a lithium ion battery. In order to achieve the above purpose, the invention adopts the following technical scheme: In a first aspect, the invention provides a ternary positive electrode material, which has a general formula of LiNi xCoyMnzM1-x-y-zO2, X being more than or equal to 0.6 and less than or equal to 1, y being more than or equal to 0 and less than or equal to 0.2, z being more than or equal to 0 and M being a doping element, wherein M is one or more than one kind of Nb, W, ta, ti, hf, mo, la, ce, zr, the ternary positive electrode material is tested by an X-ray energy spectrometer EDS, the mole percent of M tested at 10keV energy is recorded as P1, the mole percent of M tested at 20keV energy is recorded as P2, and the ternary positive electrode material meets 0.2< P2/P1<0.9. Further, the ternary cathode material P2 has a value ranging from 0.1% to 2%. In a second aspect, the invention provides a preparation method of the ternary positive electrode material, which comprises the following steps: S1, mixing a nickel-cobalt-manganese ternary precursor and lithium salt according to a molar ratio of 1 (0.8-0.98), and sintering at 870-1000 ℃ in pure oxygen atmosphere to obtain an ordered superlattice intermediate; S2, mixing the ordered superlattice intermediate with the rest lithium salt, a doping agent containing transition metal M and a layer-expanding agent, and sintering in pure oxygen atmosphere to obtain a ternary anode material with the M surface layer deeply doped and containing an ordered superlattice structure; wherein the molar ratio of the ordered superlattice intermediate to the residual lithium salt is 1 (0.12-0.32). In the preparation method, the structural general formula of the nickel-cobalt-manganese ternary precursor is [ Nix 1Coy1Mnz1](OH)2 ], wherein x 1＜1,0＜y1≤0.2,0＜z1 is more than or equal to 0.6 and less than or equal to 0.2. The lithium salt is selected from one or more of lithium hydroxide, lithium carbonate and lithium nitrate. In the preparation method, the sintering heat preservation time in the step S1 is 3-8 hours. In the above preparation method, the transition metal M is one or more selected from Nb, W, ta, ti, hf, mo, la, ce, zr. And taking the middle of the ordered superlattice as a reference, wherein the mass percentage of the dopant is 0.1% -1%. In the preparation method, the expanding agent can provide metal ions with the ionic radius larger than Li +, wherein the metal ions are preferably Na +, and more preferably, the expanding agent is one or more of Na 2CO3、NaOH、CH3COONa、Na2SO4. And taking the middle of the ordered superlattice as a reference, wherein the mass percentage of the spreading agent is 0.3% -1%. In the preparation method, in the step S2, the sintering temperature is 650-820 ℃, and the heat preservation time is 10-15 h. In a second aspect, the present invention provides a ternary positive electrode material prepared by the method of any one of the preceding claims. In a third asp