Preparation Method of Lithium-Metal Composite Oxides

• US 20100227221A1
• Filed: 02/16/2007
• Published: 09/09/2010
• Est. Priority Date: 02/17/2006
• Status: Active Grant

• Current Assignee: Hanwha Chemical Corporation, LG Energy Solution Limited (LG Corporation)
• Original Assignee: Hanwha Chemical Corporation, LG Chem Limited (LG Corporation)
• Inventors: Lee, Yong-Tae, Lee, Joo-Hyeong, Hahn, Young-Sik, Choy, Sang-Hoon, Bang, Eui-Yong, Jang, Min-Chul, Lee, Ki-Young, Song, Kyu-Ho, Chang, Sung-Kyun, Myeong, Wan-Jae, Cho, Myung-Ho
• Granted Patent: US 8,895,190 B2
• Time in Patent Office: Days
• US Class Current: 429/231.950
• CPC Class Codes: C01G 45/1228 of the type [MnO2]n- , e.g. LiMnO2, Li[MxMn1-x]O2
• CPC Class Codes: C01G 51/50 of the type [MnO2]n- , e.g. Li(CoxMn1-x)O2, Li(MyCoxMn1-x-y)O2
• CPC Class Codes: C01G 53/50 of the type [MnO2]n- , e.g. Li(NixMn1-x)O2, Li(MyNixMn1-x-y)O2
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2002/74 by peak-intensities or a ratio thereof only
• CPC Class Codes: C01P 2002/86 by NMR- or ESR-data
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/32 Spheres
• CPC Class Codes: C01P 2004/61 Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C01P 2006/11 Powder tap density
• CPC Class Codes: C01P 2006/12 Surface area
• CPC Class Codes: C01P 2006/13 thermal stability thereof at high temperatures
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 4/485 of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy H01M4/505, H01M4/525 take precedence
• CPC Class Codes: H01M 4/505 of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 20/54 using solvents, e.g. supercritical solvents or ionic liquids
• CPC Class Codes: Y10T 29/49108 : Electric battery cell making

Abstract

Disclosed is a method for preparing a lithium-metal composite oxide, the method comprising the steps of: (a) mixing an aqueous solution of one or more transition metal-containing precursor compounds with an alkalifying agent and a lithium precursor compound to precipitate hydroxides of the transition metals; (b) mixing the mixture of step (a) with water under supercritical or subcritical conditions to synthesize a lithium-metal composite oxide, and drying the lithium-metal composite oxide; and (c) subjecting the dried lithium-metal composite oxide either to calcination or to granulation and then calcination. Also disclosed are an electrode comprising the lithium-metal composite oxide, and an electrochemical device comprising the electrode. In the disclosed invention, a lithium-metal composite oxide synthesized based on the prior supercritical hydrothermal synthesis method is subjected either to calcination or to granulation and then calcination. Thus, unlike the prior dry calcination method or wet precipitation method, a uniform solid solution can be formed and the ordering of metals in the composite oxide can be improved. Accordingly, the lithium-metal composite oxide can show crystal stability and excellent electrochemical properties.

Claims

1. A method for preparing a lithium-metal composite oxide, the method comprising the steps of:

(a) mixing an aqueous solution of one or more transition metal-containing precursor compounds with an alkalifying agent and a lithium precursor compound to precipitate hydroxides of the transition metals;

(b) mixing the mixture of step (a) with water under supercritical or subcritical conditions to synthesize a lithium-metal composite oxide, and drying the lithium-metal composite oxide; and

(c) subjecting the dried lithium-metal composite oxide either to calcination or to granulation and then calcination.

2. The method of claim 1, wherein the step (c) can grow crystals of the lithium-metal composite oxide synthesized in the step (b) and, at the same time, can increase the adhesion between the crystals.

3. The method of claim 1, wherein the transition metal-containing precursor compounds are selected from the group consisting of transition metal-containing nitrates, sulfates and acetates, and the lithium precursor compound is selected from the group consisting of lithium hydroxide and lithium nitrate.

4. The method of claim 1, wherein the alkalifying agent is a compound selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides and ammonia compounds.

5. The method of claim 1, wherein the molar ratio of lithium to the transition metals (Li/transition metals) in the step (b) is 1.0-20.

6. The method of claim 1, wherein the alkali equivalent ratio of the mixture in step (b) is in a range of 1-10.

7. The method of claim 1, wherein the water under supercritical or subcritical conditions in the step (b) has a pressure of 180-550 bar and a temperature of 200-700°

C.

8. The method of claim 1, which is carried out in a first mixer, a second continuous mixer and a reactor connected with the mixers, in which the step (a) is carried out in the first mixer to form a uniform precipitate of the transition metal hydroxides, and lithium hydroxide present in the mixture in the first mixer is subjected to the step (b) in the second mixer and reactor connected with the first mixer so as to synthesize the lithium-metal composite oxide in which lithium ions are inserted into the precipitated transition metal hydroxides.

9. The method of claim 1, wherein the granulation in the step (c) is carried out using a method selected from the group consisting of a spray drying method, a fluidized bed drying method and a vibration drying method.

10. The method of claim 1, wherein the calcination in the step (c) is carried out at a temperature of 600-1200°

C.

11. The method of claim 1, wherein at least one additive selected from the group consisting of a binder, a sintering aid, a doping agent, a coating agent, a reducing agent, an oxidizing agent, an acid, carbon, a carbon precursor, metal oxide and a lithium compound is additionally used before, after or during any one step of the steps (a) to (c).

12. The method of claim 11, wherein the additive is a compound containing at least one element selected from the group consisting of Li, Al, Zr, Mg, Ti, C, P, halogen, and combinations thereof.

13. A lithium-metal composite oxide prepared according to the method of claim 1.

14. The lithium-metal composite oxide of claim 13, which is any one of compounds represented by the following formulas 1 to 4:

Li_1+aA<sub>1−

x</sub>C_xO<sub>2−

b</sub>X_b (−

0.5≦

a≦

+0.5, 0≦

b≦

+0.1, 0≦

x≦

+0.1) 

 

[Formula 1];

Li₁₊A_xB<sub>2−

x−

y</sub>C_yO<sub>4−

b</sub>X_b (−

0.5≦

a≦

+0.5, 0≦

b≦

+0.1, 0≦

x≦

+2, 0≦

y≦

0.1) 

 

[Formula 2];

Li_1+aA<sub>1−

x</sub>C_x(YO<sub>4−

b</sub>X_{b) (−}

0.5≦

a≦

+0.5, 0≦

b≦

+0.1, 0≦

x≦

+0.1) 

 

[Formula 3]; and

Li_1+aA<sub>2−

x</sub>C_x(YO<sub>4−

b</sub>X_b)₃ (−

0.5≦

a≦

+0.5, 0≦

b≦

+0.1, 0≦

x≦

+0.1) 

 

[Formula 4],

wherein A is at least one element selected from among transition metals having a six-coordinate structure;

B is at least one element selected from among transition metals having a four-coordinate structure;

C is at least one element selected from the group consisting of alkaline earth metals and Group 3B elements;

X is at least one element selected from the group consisting of Groups 5B, 6B and 7B elements; and

Y is at least one element selected from metalloids or metals having a four-coordinate structure.

15. The lithium-metal composite oxide of claim 14, wherein, in the formula 1, A is at least one element selected from among Ni, Co and Mn, C is at least one element selected from among Al, Mg and Ti, and X is F, S or N.

16. The lithium-metal composite oxide of claim 14, wherein, in the formula 2, B or A is at least one element selected from among Ni, Co and Mn, C is at least one element selected from among Al, Mg and Ti, and X is F, S or N.

17. The lithium-metal composite oxide of claim 14, wherein, in the formula 3 or 4, A is at least one element selected from among Fe, Mn, Co, Ni and V, Y is at least one element selected from among P, Ti, V and Si, C is at least one element selected from among Al, Mg and Ti, and X is F, S, or N.

18. The lithium-metal composite oxide of claim 13, which has a size of 1-100 μ

m.

19. An electrode comprising the lithium-metal composite oxide of claim 13.

20. An electrochemical device comprising:

(a) a cathode comprising the lithium-metal composite oxide of claim 13;

(b) an anode;

(c) a separator; and

(d) an electrolyte.

21. The electrochemical device of claim 20, which is a lithium secondary battery.