Ni-based lithium transition metal oxide

• US 20060233696A1
• Filed: 04/13/2005
• Published: 10/19/2006
• Est. Priority Date: 04/13/2005
• Status: Active Grant

• Current Assignee: LG Energy Solution Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Park, Hong-Kyu, Paulsen, Jens M., Kwon, Yong Hoon
• Granted Patent: US 7,648,693 B2
• Time in Patent Office: Days
• US Class Current: 423/594.400
• 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 53/006 Compounds containing, besides nickel, two or more other elements, with the exception of oxygen or hydrogen nickelates C01G53/40
• CPC Class Codes: C01G 53/42 containing alkali metals, e.g. LiNiO2
• 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 2002/77 by unit-cell parameters, atom positions or structure diagrams
• CPC Class Codes: C01P 2002/88 by thermal analysis data, e.g. TGA, DTA, DSC
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: C01P 2006/80 Compositional purity
• CPC Class Codes: H01M 10/052 Li-accumulators
• 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 20/129 Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines

Abstract

The present invention provides a powderous lithium transition metal oxide with the composition as represented by the below Formula and prepared by solid state reaction in air from a mixed transition metal precursor and Li₂CO₃, with being practically free of Li₂CO₃ impurity:
Li_xM_yO₂ wherein

M=M′_l-kA_k, where M′=Ni_l-a-b(Ni_1/2Mn_1/2)_aCo_b on condition of 0.65≦a+b≦0.85 and 0.1≦b≦0.4; A is a dopant; and 0≦k≦0.05; and
x+y=2 on condition of 0.95≦x≦1.05. The Ni-based lithium transition metal oxide according to the present invention has a well-layered structure, and also improved safety, cycling stability and stability against aging and low gas evolution during storage, when used as an active material for cathode of lithium secondary batteries, because it has a high sintering stability and is substantially free of soluble bases.

Moreover, the lithium transition metal oxide of the present invention can be prepared by a low-cost process using a mixed transition metal precursor and Li₂CO₃ as raw stocks and under relatively unrestricted conditions.

Claims

1. A powderous lithium transition metal oxide with the composition as represented by Formula 1 below, with practically being free of Li₂CO₃ impurity, and prepared by solid state reaction in air from a mixed transition metal precursor and Li₂CO₃:

Li_xM_yO₂  

 

(1)

wherein

M=M′

_l-kA_k, where

M′

=Ni_l-a-b(Ni_1/2Mn_1/2)_aCo_b on condition of 0.65≦

a+b≦

0.85 and 0.1≦

b≦

0.4;

A is a dopant;

0≦

k<

0.05; and

x+y=2 on condition of 0.95≦

x≦

1.05.

2. The lithium transition metal oxide according to claim 1, wherein the solid state reaction in air proceeds through a heating procedure of two steps:

(i) a cooking step at a temperature of between 700 and 950°

C. under air circulation and then (ii) a sintering step at a temperature of between 850°

C. and 1020°

C.

3. The lithium transition metal oxide according to claim 1, wherein the mixed transition metal precursor is a mixed hydroxide, mixed carbonate or mixed oxides.

4. The lithium transition metal oxide according to claim 3, wherein the mixed hydroxide, MOOH (M=Ni, Mn and Co), is prepared by an ammonia-free process.

5. The lithium transition metal oxide according to claim 1, wherein the oxide contains a small amount of soluble bases.

6. The lithium transition metal oxide according to claim 5, where a pH below 5 is achieved by adding less than 20 ml of 0.1M HCl to 200 ml of a solution, where the solution contains basically all soluble base of 10 g of the lithium transition metal oxide, the solution being prepared by a repeated soaking and decanting of the lithium transition metal oxide.

7. The lithium transition metal oxide according to claim 6, wherein the amount of 0.1M HCl necessary for achievement of pH below 5 is 10 ml.

8. The lithium transition metal oxide according to claim 1, wherein the oxide is prepared by a large-scale process under a high rate of air circulation.

9. The lithium transition metal oxide according to claim 8, wherein for the high rate of air circulation, at least 2 m³ of air (volume at room temperature) per 1 kg of the final lithium transition metal oxide is pumped into or out of a reactor.

10. The lithium transition metal oxide according to claim 9, wherein at least 10 m³ of air per 1 kg of the final lithium transition metal oxide is pumped into or out of the reactor.

11. The lithium transition metal oxide according to claim 8, wherein a heat exchanger is used to pre-warm the in-flowing air before said in-flowing air enters the reactor while cooling the out-flowing air.

12. The lithium transition metal oxide according to claim 1, wherein the solid state reaction occurs by at least two steps, including a cooking step at a temperature between 700 and 950°

C. where the transition metal precursor and the Li₂CO₃ react to form a LiMO₂ precursor, and a sintering step at a temperature between 850 and 1020°

C. where the final LiMO₂ with a well-layered crystal structure is made, in which during the cooking step large quantities of air exceeding 2 m³/kg LiMO₂ is fed into the reactor equipped with a heat exchanger to preheat the air.