Full-gradient nickel cobalt manganese positive electrode material, ruthenium oxide coated material and preparation method thereof

Patent metadata

Field	Value
Publication number	US-2020335784-A1
Application number	US-202016847048-A
Country	US
Kind code	A1
Filing date	Apr 13, 2020
Priority date	Apr 19, 2019
Publication date	Oct 22, 2020
Grant date	—

Abstract

The present invention discloses a full-gradient nickel cobalt manganese positive electrode material, a ruthenium oxide coated material and a preparation method thereof. The material has a chemical formula of LiNixCoyMn(1-x-y)O2, wherein, 0.5≤x≤0.9, 0.05≤y≤0.40, 1-x-y>0. A content of the nickel element is gradually decreased from a core portion to an outer surface of the full-gradient nickel cobalt manganese positive electrode material. A content of the manganese element is gradually increased from the core portion to the outer surface of the full-gradient nickel cobalt manganese positive electrode material. And, a content of the cobalt element is uniformly distributed in the full-gradient nickel cobalt manganese positive electrode material. The present invention also discloses a preparation method of the full-gradient nickel cobalt manganese positive electrode material. The present invention also discloses a preparation method of the ruthenium oxide coated material.

First claim

1 . A full-gradient nickel cobalt manganese positive electrode material, comprising: the material is represented by a chemical formula of LiNi x Co y Mn (1-x-y) O 2 , wherein, 0.5≤x≤0.9, 0.05≤y≤0.40, 1-x-y>0;
a content of the nickel element is gradually decreased from a core portion to an outer surface of the full-gradient nickel cobalt manganese positive electrode material,
a content of the manganese element is gradually increased from the core portion to the outer surface of the full-gradient nickel cobalt manganese positive electrode material, and
a content of the cobalt element is uniformly distributed in the full-gradient nickel cobalt manganese positive electrode material.

2 . The full-gradient nickel cobalt manganese positive electrode material according to claim 1 , wherein the full-gradient nickel cobalt manganese positive electrode material is in the form of spherical particles having an average particle diameter of 3-10 μm.

3 . A method of preparing a full-gradient nickel cobalt manganese positive electrode material according to claim 1 , comprising:
(1) pumping a cobalt manganese solution into a vessel containing a nickel cobalt or nickel cobalt manganese solution having a high nickel content to form a mixed solution, and simultaneously pumping the mixed solution into a reaction kettle containing an ammonia solution, and simultaneously adjusting the ammonia concentration of the reaction system by ammonia water, adjusting the pH value of the reaction system with a hydroxide precipitant solution, and stirring to carry out a coprecipitation reaction until the average particle diameter of the particles being 3-10 μm to obtain a slurry containing a precursor of the full-gradient nickel cobalt manganese positive electrode material; (2) stirring the slurry containing the precursor of the full-gradient nickel cobalt manganese positive electrode material obtained in the step (1), aging, filtering, washing, and drying to obtain a precursor of the full-gradient nickel cobalt manganese positive electrode material; and, (3) adding a lithium source in the precursor of the full-gradient nickel cobalt manganese positive electrode material obtained in the step (2), grinding, pre-sintering, and sintering to obtain a full-gradient nickel cobalt manganese positive electrode material.

4 . The method of preparing a full-gradient nickel cobalt manganese positive electrode material according to claim 3 , wherein in step (1), the cobalt manganese solution is fed at a rate of 5-18 mL/h; the mixed solution is fed at a rate of 50-100 mL/h;
in the cobalt manganese solution, a concentration of metal ions is 0.2-1.0 mol/L, a molar percentage of Co to total metal ions is 10-40%, and a molar percentage of Mn to total metal ions is 60-90%, a total of Co and Mn ions is 100%; in the nickel cobalt or nickel cobalt manganese solution having a high nickel content, a concentration of metal ions is 1-3 mol/L, and a molar percentage of Ni to total metal ions is 60-95%, a molar percentage of Co to total metal ions is 5-40%, a molar percentage of Mn to total metal ions is 0-30%, and a total of Ni, Co and Mn ions is 100%; a volume ratio of ammonia solution, cobalt manganese solution and nickel cobalt or nickel cobalt manganese solution having a high nickel content in the reaction kettle is 1-2:0.1-0.2:1; a molar concentration of the ammonia solution is 0.2-0.5 mol/L; the ammonia concentration of the reaction system is adjusted with ammonia water to keep at 0.3-0.5 mol/L; a mass fraction of ammonia water used to adjust the ammonia concentration of the reaction system is 20-28%; a pH of the reaction system is maintained at 10.5-11.6 adjusted by the hydroxide precipitant solution; a molar concentration of the hydroxide precipitant solution is 5-10 mol/L; and the hydroxide precipitant is one or more selected from the group consisting of sodium hydroxide, potassium hydroxide and lithium hydroxide; a stirring speed of the coprecipitation reaction is 600-1200 r/min, and the temperature is 50-70° C.; the cobalt manganese solution is a mixed solution of soluble cobalt salt and soluble manganese salt; the nickel cobalt or nickel cobalt manganese solution having a high nickel content is a mixed solution of a soluble nickel salt and a soluble cobalt salt or a soluble nickel salt, a soluble cobalt salt and a soluble manganese salt; the soluble nickel salt is one or more selected from the group consisting of nickel sulfate, nickel nitrate, nickel acetate or nickel chloride; the soluble cobalt salt is one or more selected from the group consisting of cobalt sulfate, cobalt nitrate, cobalt acetate and cobalt chloride; the soluble manganese salt is one or more selected from the group consisting of manganese sulfate, manganese nitrate, manganese acetate or manganese chloride.

5 . The method of preparing a full-gradient nickel cobalt manganese positive electrode material according to claim 3 wherein in the step (2), a stirring speed is 400-800 r/min; and the aged temperature is 50-80° C., and the aged time is 5-15h; the drying temperature is 50-100° C., and the drying time is 5-15h; in the step (3), the molar ratio of lithium element in the lithium source to total moles of nickel, cobalt and manganese in the precursor of the full-gradient nickel cobalt manganese positive electrode material is 1.01-1.07:1; the lithium source is one or more selected from the group consisting of lithium hydroxide, lithium nitrate, lithium carbonate, lithium oxalate or lithium acetate, and hydrates thereof, the grinding speed is 500-1000 r/min, and the grinding time is 5-10 min; the pre-sintering temperature is 350-550° C., and the pre-sintering time is 3-6h; the sintering temperature is 650-950° C., and the sintering time is 8-24h.

6 . A ruthenium oxide coated full-gradient nickel cobalt manganese positive electrode material, characterized in, the material is obtained by coating a full-gradient nickel cobalt manganese positive electrode material according to claim 1 with a ruthenium oxide.

7 . The ruthenium oxide coated full-gradient nickel cobalt manganese positive electrode material according to claim 6 , wherein the ruthenium oxide coated full-gradient nickel cobalt manganese positive electrode material is represented by a chemical formula of LiNi x Co y Mn (1-x-y) O 2 @RuO 2 , wherein, 0.5≤x≤0.9, 0.05≤y≤0.40, 1-x-y>0; a mass percentage of the ruthenium oxide is 0.5-5.0%; the ruthenium oxide coated full-gradient nickel cobalt manganese positive electrode material is in the form of spherical particles having an average particle diameter of 3-10 m; the coating layer of the ruthenium oxide has a thickness of 2-10 nm.

8 . A method of preparing a ruthenium oxide coated full-gradient nickel cobalt manganese positive electrode material according to claim 6 , characterized in, comprising:
(1) mixing the full-gradient nickel cobalt manganese positive electrode material with a ruthenium source in an alcohol solution, heating and stirring the reaction in a closed atmosphere of an ammonia gas, and then evaporating to obtain a mixed powder; and, (2) heat-treating the mixed powder obtained in the step (1) in an oxygen-containing atmosphere to obtain a ruthenium oxide coated full-gradient nickel cobalt manganese positive electrode material.

9 . The method of preparing a ruthenium oxide coated full-gradient nickel cobalt manganese positive electrode material according to claim 8 , wherein in the step (1), a molar ratio of ruthenium element in the ruthenium source to total moles of nickel, cobalt and manganese in the full-gradient nickel cobalt manganese positive electrode material is 0.005-0.050:1; the ruthenium source is one or more selected from the group consisting of ruthenium chloride, ruthenium nitrate, rutheniu

Assignees

• Univ Central South

Inventors

• Tong Hui
• Zhou Qijie
• Zhang Bao
• Wang Xu
• Yao Yingying
• Yu Wanjing
• Zheng Junchao

Classifications

• H01M4/1391

  of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M4/525 Primary

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M2004/028

  Positive electrodes · CPC title