CN-116835673-B - Positive electrode material, preparation method thereof and lithium ion battery

Abstract

The invention relates to the technical field of lithium ion battery materials, in particular to a positive electrode material, a preparation method thereof and a lithium ion battery. The preparation method of the positive electrode material comprises the following steps of (a) carrying out coprecipitation reaction on a mixed solution formed by a manganese source, a nickel source and a doped metal source under the action of a precipitator to obtain a coprecipitation precipitate, (b) calcining the coprecipitation precipitate to obtain a precursor, (c) mixing the precursor with a lithium source, and then calcining in an oxygen-enriched atmosphere to obtain the positive electrode material, wherein the molar ratio of the doped metal source to the manganese source is (0.001-0.08) to 1 in terms of doped metal elements and Mn respectively. The cathode material prepared by the preparation method can realize the purpose of cladding doping co-modification through one-step addition, improves the stability of the lithium nickel manganese oxide cathode material, greatly simplifies the production process and is beneficial to large-scale commercial use of the material.

Inventors

• LIU TING
• WAN YUANXIN
• CHEN MENGLONG
• LI MENGNAN
• LAN QUAN
• KONG LINGYONG

Assignees

• 佛山市德方纳米科技有限公司
• 深圳市德方纳米科技股份有限公司

Dates

Publication Date

20260512

Application Date

20230818

Claims (15)

1. 1. The preparation method of the positive electrode material is characterized by comprising the following steps: (a) Under the action of a precipitator, performing coprecipitation reaction on a mixed solution formed by a manganese source, a nickel source and a doped metal source to obtain a coprecipitation precipitate; (b) Calcining the co-deposited precipitate to obtain a precursor; (c) Mixing the precursor with a lithium source, and calcining in an oxygen-enriched atmosphere to obtain a lithium nickel manganese oxide anode material, wherein the oxygen content in the oxygen-enriched atmosphere is more than or equal to 80 percent, and the oxygen content refers to volume fraction; Wherein the molar ratio of the doped metal source to the manganese source is (0.001-0.08) 1, and the molar ratio of the manganese source to the nickel source is (0.2-0.35), calculated as Mn and Ni, respectively; In the step (b), the calcination temperature is 300-500 ℃, and the calcination time is 2-8 hours; the doped metal source comprises an organic doped metal source, the doped metal source is used as a doped source and a cladding source at the same time, in the process of mixing and calcining with a lithium source, lithium nickel manganese oxide grows in a nucleation mode, part of doped metal doped in a nickel manganese oxide crystal lattice seeps out from the inside to the outer surface of a crystal nucleus, the doped metal source is oxidized to form metal oxide in an oxygen-enriched atmosphere, and a compact protective layer is constructed on the surface of the crystal nucleus of the lithium nickel manganese oxide in situ.
2. 2. The method of producing a positive electrode material according to claim 1, wherein the doped metal source includes at least one of a titanium source, an aluminum source, a zinc source, a chromium source, a magnesium source, a zirconium source, a copper source, and an iron source.
3. 3. The method for producing a positive electrode material according to claim 2, wherein the titanium source includes at least one of tetrabutyl titanate and titanyl sulfate.
4. 4. The method for producing a positive electrode material according to claim 2, wherein the zinc source comprises at least one of zinc gluconate, zinc methionine, zinc lactate, zinc glycyrrhizate, and zinc citrate.
5. 5. The method of preparing a positive electrode material according to claim 2, wherein the chromium source comprises chromium nitrate.
6. 6. The method for producing a positive electrode material according to claim 2, wherein the magnesium source comprises at least one of magnesium ascorbate, magnesium monopersulfate hexahydrate, magnesium peroxodisulfate, magnesium monoethylfumarate, magnesium abietate, and magnesium nitrate.
7. 7. The method for producing a positive electrode material according to claim 2, wherein the zirconium source comprises at least one of zirconium carboxylate, zirconium phosphate, zirconium nitrate and zirconium 1-butoxide, and the copper source comprises at least one of copper nitrate, copper acetylide, phenyl copper, alkyl copper, copper acid chloride and copper acetate.
8. 8. The method of producing a positive electrode material according to claim 2, wherein the iron source includes at least one of ferrous lactate, ferric citrate, and ferric glycinate.
9. 9. The method for preparing a positive electrode material according to claim 1, wherein in the coprecipitation reaction, the pH of the system is controlled to be 5.75 to 6.1.
10. 10. The method for preparing a positive electrode material according to claim 9, wherein the pH of the system is controlled by a slow release agent, wherein the slow release agent is at least one of sulfuric acid, phosphoric acid and hydrochloric acid.
11. 11. The method for producing a positive electrode material according to claim 1, wherein the precipitant is an alkaline solution.
12. 12. The method for producing a positive electrode material according to claim 11, wherein the precipitant includes at least one of an aqueous solution of a carbonate and an aqueous solution of a hydroxide.
13. 13. The method for preparing a positive electrode material according to claim 11, wherein the amounts of the manganese source, the nickel source and the lithium source are respectively calculated as Mn, ni and Li, and Li (mn+ni) =1 (0.95-1.05).
14. 14. The method for preparing a positive electrode material according to claim 1, wherein in the step (C), the calcination comprises primary calcination and secondary calcination, wherein the primary calcination is performed at 550-1100 ℃, the primary calcination is performed for 8-24 hours, the secondary calcination is performed at 450-800 ℃, and the secondary calcination is performed for 15-48 hours.
15. 15. The method according to claim 14, wherein the temperature is raised to 550-1100 ℃ at a temperature raising rate of 0.5-10 ℃ per minute in the primary calcination, and the temperature is lowered to 450-800 ℃ at a temperature lowering rate of 0.5-2 ℃ per minute in the secondary calcination.

Description

Positive electrode material, preparation method thereof and lithium ion battery Technical Field The invention relates to the technical field of lithium ion battery materials, in particular to a positive electrode material, a preparation method thereof and a lithium ion battery. Background Lithium ion batteries are widely applied to various fields such as 3C electronic products, power automobiles, energy storage power stations and the like due to high energy density, small self-discharge, no memory effect and long cycle life, and are research hot spots in the current new energy storage and conversion system. The cost and mass of the positive electrode material in the battery are the highest, and therefore are very important for the performance and cost impact of the battery. Spinel structured lithium nickel manganese oxide materials are receiving attention because of their high energy density as an assembled battery of electrode materials due to their ultra-high operating voltage. However, under high voltage, the damage of severe side reaction between the electrode material and the electrolyte to the service life of the whole battery is the biggest obstacle for limiting the commercialization of the lithium nickel manganese oxide material, so how to improve the stability of the lithium nickel manganese oxide is the key for accelerating the commercialization process of the high voltage lithium nickel manganese oxide material. Surface coating and element doping are conventional effective means for improving the stability of an electrode material, and are also effective for lithium nickel manganese oxide, but the stability deterioration of the electrode material is further aggravated by the presence of nickel and manganese due to higher working voltage of lithium nickel manganese oxide compared with other cathode materials, the stability of the material cannot be completely improved by a single modification strategy, and conventional coating tends to be uneven in coating, so that the stability improvement of the lithium nickel manganese oxide material is not obvious. In view of this, the present invention has been made. Disclosure of Invention The invention aims to provide a preparation method of a positive electrode material, which realizes doping and cladding simultaneously by a one-step method and improves the stability of the positive electrode material. Another object of the present invention is to provide a positive electrode material having good stability. It is still another object of the present invention to provide a lithium ion battery including the above positive electrode material. In order to achieve the above object of the present invention, the present invention provides, in one aspect, a method for preparing a positive electrode material, comprising the steps of: (a) Under the action of a precipitator, performing coprecipitation reaction on a mixed solution formed by a manganese source, a nickel source and a doped metal source to obtain a coprecipitation precipitate; (b) Calcining the co-deposited precipitate to obtain a precursor; (c) Mixing the precursor with a lithium source, and calcining in an oxygen-enriched atmosphere to obtain the anode material; Wherein the molar ratio of the doped metal source to the manganese source is (0.001-0.08) 1 in terms of doped metal element and Mn, respectively. Further, the doped metal source includes at least one of a titanium source, an aluminum source, a zinc source, a chromium source, a magnesium source, a zirconium source, a copper source, and an iron source. Further, the titanium source comprises at least one of tetrabutyl titanate, tetraethyl titanate, metatitanic acid, titanyl sulfate and titanium dioxide, the aluminum source comprises at least one of aluminum alkyl, aluminum diethyl chloride and aluminum silicate, the zinc source comprises at least one of zinc acetate, zinc oxalate, zinc gluconate, zinc methionine, zinc lactate, zinc glycyrrhizate and zinc citrate, the chromium source comprises at least one of dichromic acid, chromic anhydride, basic chromium sulfate, chromium nitrate and chromium oxide green, the magnesium source comprises at least one of magnesium ascorbate, magnesium monoperoxyphthalate hexahydrate, magnesium peroxyphthalate, magnesium monoethyl fumarate, magnesium rosinate and magnesium nitrate, the zirconium source comprises at least one of zirconium carboxylate, zirconium phosphate, zirconium nitrate and zirconium 1-butoxide, the copper source comprises at least one of copper nitrate, copper acetylene, copper phenyl, copper alkyl, copper chloride and cuprous acetate, and the iron source comprises at least one of ferrous lactate, ferric citrate, ferrocene, ferrocyanide and glycine. Further, the dopant metal source comprises an organic dopant metal source. Further, in the coprecipitation reaction, the pH of the system is controlled to be 5.75-6.1. Further, the pH of the system is controlled by a slow release agent, wherein the sl