Layered lithium metal oxides free of localized cubic spinel-like structural phases and methods of making same

A spinel structure, layered crystal structure technology, applied in the direction of alkali metal oxide/hydroxide, alkali metal compound, lithium oxide;/hydroxide, etc., can solve problems such as battery cycle problems, achieve good Structural stability, effect of uniform electrochemical properties

Inactive Publication Date: 2002-02-13
UMCORE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Thus, the presence of even less cubic spinel-like phases, even at levels undetectable by bulk techniques like powder x-ray diffraction (XRD), can cause battery cycling problems

Method used

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  • Layered lithium metal oxides free of localized cubic spinel-like structural phases and methods of making same
  • Layered lithium metal oxides free of localized cubic spinel-like structural phases and methods of making same
  • Layered lithium metal oxides free of localized cubic spinel-like structural phases and methods of making same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Industrial LiCoO 2 The sample (sample 1) was heated to 950°C for 1 hour, then rapidly cooled by removing the sample directly from the hot zone and spreading the sample flat on a stainless steel pan at room temperature. The cooling time from 950°C to room temperature is estimated to be about 10 minutes. The sample 1 and the fast cooling sample (sample 2) were used as positive electrode materials for different electrochemical cells, and each battery used lithium metal as the negative electrode coin cell structure. NRC2325 coin cell components and Celgard 3501 separators were used. The electrolyte is 1M LiPE 6 A 50:50 mixture of ethylene carbonate and dimethyl carbonate. The positive electrode contains 85% active material (by weight), 10% super S TM Carbon black and 5% polyvinylidene fluoride (PVDF) as polymer binder were coated on aluminum foil. The cycle test is carried out between 3.0V and 4.3V, and a constant current of C / 3 (3 hours for complete charge and dischar...

Embodiment 2

[0049] Mixed stoichiometric Li 2 CO 3 and Co 3 o 4 , then heated from room temperature to 950 °C at a rate of 3.75 °C / min, held at 950 °C for 5 hours, and then cooled to room temperature at a rate of about 3.7 °C / min (the total cooling time was slightly longer than 4 hours). The obtained compound was sample 3.

[0050] Mixed stoichiometric Li 2 CO 3 and Co 3 o 4 , then heated from room temperature to 950 °C at a rate of 3.75 °C / min, maintained at 950 °C for 5 hours, and then cooled to room temperature at a rate of about 8 °C / min (the entire cooling time was only less than 2 hours). The obtained compound was sample 4.

[0051] Sample 3 and sample 4 were subjected to cycle detection according to the method of Example 1. Figure 7 The cycle characteristics of sample 3 and sample 4 were compared. Such as Figure 7 As shown, the cycle performance of sample 4 prepared according to the present invention is better than that of sample 3.

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Abstract

The present invention includes substantially single-phase lithium metal oxide compounds having hexagonal layered crystal structures that are substantially free of localized cubic spinel-like structural phases. The lithium metal oxides of the invention have the formula LialphaMbetaAgammaO2, wherein M is one or more transition metals, A is one or more dopants having an average oxidation state N such that +2.5<=N<=+3.5, 0.90<=alpha<=1.10, and beta+gamma=1. The present invention also includes dilithiated forms of these compounds, lithium and lithium-ion secondary batteries using these compounds as positive electrode materials, and methods of preparing these compounds.

Description

field of invention [0001] The invention relates to a lithium metal oxide used as positive electrode material in lithium and lithium ion secondary batteries and a preparation method thereof. Background of the invention [0002] The formula is LiMO 2 Lithium metal oxides, where M is a transition metal, are important cathode (cathode) materials for rechargeable Li batteries and Li-ion batteries. LiMO 2 Examples of compounds include LiCoO 2 , LiNiO 2 and LiMnO 2 . Currently LiCoO 2 Used as cathode material in most commercially available lithium and lithium-ion batteries. [0003] Even in the same compound, LiMO 2 Compounds can have different crystal structures and phases. For example, LiCoO synthesized above 700 °C 2 has a similarity to α-NaFeO 2 hexagonal layered structure. However, LiCoO synthesized at about 400 °C 2 , with a similarity to Li 2 Ti 2 o 4 cubic spinel-like structure. But except for a small distortion of the layered structure in the direction per...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01D1/00C01D15/00C01G1/00C01G1/02C01G51/00C01G51/04H01M4/02H01M4/131H01M4/1391H01M4/48H01M4/485H01M4/52H01M4/525H01M10/052H01M10/0525H01M10/36
CPCH01M4/525C01G53/42C01P2002/32C01G53/44C01P2006/40C01P2002/74C01G51/44C01P2002/54H01M10/0525H01M4/485H01M4/1391C01G45/1228Y02E60/122H01M2004/028C01P2002/72C01P2002/88C01G1/02H01M10/052C01P2002/52C01G51/42C01P2002/86H01M4/131Y02E60/10C01G51/04C01D15/02C01G51/006C01P2002/20
Inventor Y·高M·亚克勒瓦H·H·瓦格J·F·恩格尔
Owner UMCORE
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