CN-122025603-A - Doped coated ternary positive electrode material, preparation method thereof and lithium ion battery

CN122025603ACN 122025603 ACN122025603 ACN 122025603ACN-122025603-A

Abstract

The invention relates to a doped cladding ternary positive electrode material, a preparation method thereof and a lithium ion battery, wherein the doped cladding ternary positive electrode material comprises a nickel-cobalt-manganese ternary positive electrode material core and a cladding layer; the nickel-cobalt-manganese ternary anode material core comprises a doped metal element, wherein the doped metal element comprises any one or a combination of at least two of Mg, zr and Mo, and the material of the coating layer comprises at least one metal oxide. According to the invention, the nickel-cobalt-manganese ternary anode material is doped and coated at the same time, so that the electrochemical performance of the material is improved, the obtained material has excellent cycle performance, and the voltage attenuation of the material in the discharge process is greatly reduced. The preparation method of spray pyrolysis is adopted, so that the ternary oxide precursor with uniform particle size can be prepared in one step, no liquid phase product is produced, the preparation efficiency is high, the cost is low, and the mass production is facilitated.

Inventors

XU KAIHUA
ZHU XIAOSHUAI
ZHANG KUN
LI CONG
Yue Xianjin
JIA DONGMING

Assignees

荆门市格林美新材料有限公司
格林美股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260323

Claims (10)

1. The doped cladding ternary positive electrode material is characterized by comprising a nickel-cobalt-manganese ternary positive electrode material core and a cladding layer; The nickel-cobalt-manganese ternary positive electrode material core comprises a doped metal element, wherein the doped metal element comprises any one or a combination of at least two of Mg, zr and Mo; the material of the cladding layer comprises at least one metal oxide.
2. A doped coated ternary cathode material according to claim 1, wherein the doped metallic elements comprise Mg, zr and Mo; preferably, the mass ratio of the Mg to the Zr to the Mo is 1 (0.5-2): 0.8-1.2; preferably, the metal oxide comprises any one or a combination of at least two of Al 2 O 3 、La 2 O 3 、ZrO 2 , mgO, or TiO 2 .
3. A method for preparing the doped coated ternary cathode material according to claim 1 or 2, wherein the preparation method comprises the following steps: (1) Sequentially atomizing, drying and pyrolyzing the precursor solution to obtain a ternary oxide precursor; The precursor solution comprises a nickel-cobalt-manganese mixed salt solution, a doped metal salt solution, a solvent and a chelating agent; the doped metal salt in the doped metal salt solution comprises any one or a combination of at least two of magnesium salt, zirconium salt or molybdenum salt; (2) Uniformly mixing a lithium source and the ternary oxide precursor in the step (1), and sintering to obtain a ternary positive electrode material core; (3) Uniformly mixing a metal source and the ternary positive electrode material core in the step (2), and performing heat treatment to obtain a doped coated ternary positive electrode material; The metal source comprises a metal oxide.
4. The preparation method according to claim 3, wherein the total mass concentration of metal elements in the doped metal salt solution in the step (1) is 5g/L to 20g/L; preferably, the content of the doped metal in the doped metal salt in the step (1) in the ternary oxide precursor is 1000ppm to 3000ppm; Preferably, the doping metal salt in step (1) comprises magnesium salt, zirconium salt and molybdenum salt, and the doping metal comprises Mg, zr and Mo; preferably, the mass ratio of the Mg to the Zr to the Mo is 1 (0.5-2): 0.8-1.2; preferably, the total mass concentration of metal elements in the nickel-cobalt-manganese mixed salt solution in the step (1) is 300 g/L-400 g/L; Preferably, in the nickel-cobalt-manganese mixed salt solution in the step (1), the molar ratio of Ni to Co to Mn is Ni to Co to Mn=x to y to z, wherein x+y+z=10, x is 8-10,0.1-y-1, and z is 0.1-1; preferably, the total mass concentration of the metal elements in the precursor solution in the step (1) is 150 g/L-200 g/L.
5. The method according to claim 3 or 4, wherein the precursor solution in step (1) is prepared by first mixing a nickel cobalt manganese mixed salt solution, a doped metal salt solution and a solvent, and then adding a chelating agent for second mixing; preferably, the temperature of the first mixing is 70-100 ℃; Preferably, the first mixing time is 4-10 hours; preferably, the temperature of the second mixing is 60-90 ℃; Preferably, the second mixing time is 2-6 hours; preferably, the chelating agent comprises any one or a combination of at least two of citric acid, formic acid or amino acids; preferably, the addition amount of the chelating agent is 0.5-3 wt% of the total mass of the nickel-cobalt-manganese mixed salt solution, the doped metal salt solution and the solvent.
6. The method according to any one of claims 3 to 5, wherein the atomizing method in step (1) comprises feeding the precursor solution to a two-fluid atomizing nozzle by a feeding device; Preferably, the conveying flow of the conveying device is 10L/h-15L/h; preferably, the drying temperature in the step (1) is 150-300 ℃.
7. The method according to any one of claims 3 to 6, wherein the pyrolysis in step (1) includes a first-stage pyrolysis, a second-stage pyrolysis and a third-stage pyrolysis which are sequentially performed; Preferably, the temperature of the first pyrolysis is 500-600 ℃; preferably, the temperature of the two-stage pyrolysis is 700-800 ℃; Preferably, the temperature of the three-stage pyrolysis is 800-1000 ℃.
8. The method according to any one of claims 3 to 7, wherein the molar ratio of the lithium element in the lithium source in step (2) to the total metal element in the ternary oxide precursor in step (1) is (1.05 to 1.10): 1; preferably, the sintering heat preservation temperature in the step (2) is 750-950 ℃; Preferably, the sintering heat preservation time in the step (2) is 8-20 h.
9. The preparation method according to any one of claims 3 to 8, wherein the mass ratio of the metal source in the step (3) to the ternary cathode material core in the step (2) is (0.001 to 0.03): 1; Preferably, the metal oxide of step (3) comprises any one or a combination of at least two of Al 2 O 3 、La 2 O 3 、ZrO 2 , mgO or TiO 2 ; Preferably, the heat preservation temperature of the heat treatment in the step (3) is 1000-1300 ℃; preferably, the heat preservation time of the heat treatment in the step (3) is 8-20 h.
10. A lithium ion battery, characterized in that the lithium ion battery comprises the doped coated ternary cathode material according to claim 1 or 2, or the doped coated ternary cathode material prepared by the preparation method according to any one of claims 3 to 9.

Description

Doped coated ternary positive electrode material, preparation method thereof and lithium ion battery Technical Field The invention relates to the technical field of preparation of ternary cathode materials, in particular to a doped coated ternary cathode material, a preparation method thereof and a lithium ion battery. Background The commercialized power battery positive electrode material mainly comprises a ternary positive electrode material and lithium iron phosphate, wherein the ternary positive electrode material is dominant in the global power battery market due to the excellent energy density, rate capability and low temperature resistance. The ternary positive electrode materials can be classified into low nickel ternary (nickel content less than 60%) and high nickel ternary positive electrode materials (nickel content greater than or equal to 60%) according to the nickel content. The high-nickel ternary positive electrode material has high specific capacity, stable low-temperature performance, low cobalt content and low raw material cost, and is one of high-performance lithium ion battery positive electrode materials with great development value. At present, a traditional method, namely a coprecipitation method, is adopted to prepare a ternary positive electrode material commercially, for example, a nickel cobalt manganese hydroxide precursor is synthesized firstly, ni 2＋、Co2＋ and Mn 2＋ ions are formed into complex ions with NH 3, the pH is controlled to be 10-11 by adding NaOH, the temperature of a solution is controlled to be about 55 ℃ for preventing Mn 2＋ from being oxidized, a certain stirring speed is maintained under the protection of nitrogen to ensure mass transfer, and then the precursor is mixed with a lithium source solid phase and then sintered at a high temperature to obtain the ternary positive electrode material. Although the method can realize mass production, the process parameters are strictly controlled, and the method has the defects of long flow, large wastewater yield, non-uniform solid-phase lithium mixing and the like. In addition, aiming at the problems of the structure and the interface of the high-nickel ternary cathode material, doping and/or cladding of elements are generally selected for improvement and solution, and the doping of the elements also faces the problems of larger difference between the precipitation coefficient (Ksp) of the doping elements and the precipitation coefficient of nickel, cobalt and manganese, further the problems of increased difficulty in controlling the reaction process, uneven precipitation of the doping elements and the like are caused. Therefore, how to provide a doped coated ternary positive electrode material and a preparation method thereof has the advantages of short process flow, uniform element doping, low cost and better electrochemical performance and cycle performance of the positive electrode material, and becomes a current urgent problem to be solved. Disclosure of Invention In order to solve the technical problems, the invention provides a doped cladding ternary positive electrode material, a preparation method thereof and a lithium ion battery. According to the invention, the nickel-cobalt-manganese ternary anode material is doped and coated at the same time, so that the electrochemical performance of the material is improved, the obtained material has excellent cycle performance, and the voltage attenuation of the material in the discharge process is greatly reduced. The preparation method of spray pyrolysis is adopted, so that the ternary oxide precursor with uniform particle size can be prepared in one step, no liquid phase product is produced, the preparation efficiency is high, the cost is low, and the mass production is facilitated. To achieve the purpose, the invention adopts the following technical scheme: in a first aspect, the invention provides a doped cladding ternary cathode material, which comprises a nickel-cobalt-manganese ternary cathode material core and a cladding layer; The nickel-cobalt-manganese ternary positive electrode material core comprises a doped metal element, wherein the doped metal element comprises any one or a combination of at least two of Mg, zr and Mo; the material of the cladding layer comprises at least one metal oxide. According to the invention, the doping elements are added to regulate the crystal structure, inhibit cation mixing, improve lithium ion transmission kinetics and enhance interface stability, so that the electrochemical performance of the nickel-cobalt-manganese ternary cathode material is obviously improved, wherein Mg doping can occupy lithium layer position points to play a role of 'support' so as to stabilize the layered structure, inhibit Li ＋/Ni2＋ mixing, and improve the electronic conductivity of the material due to the introduction of low valence state (Mg 2＋) of the material, thus synergistically improving the cycle stability and rate capability, zr doping mainl