Lithium Metal Composite Oxide Calcination for Higher Crystallinity
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Solution Overview
Problem
Current methods for producing lithium metal composite oxides do not adequately improve the crystallinity of these materials, which is essential for enhancing the cycle characteristics of lithium secondary batteries.
Innovation Solution
A method involving calcination of a raw material mixture containing a metal composite compound and a lithium compound in a gas mixture with specific oxygen, moisture, and carbon oxide concentrations at temperatures above 600°C, followed by a cooling step with a dew point of −15°C or lower, to produce lithium metal composite oxides that satisfy a general formula, thereby improving crystallinity and cycle retention rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional calcining methods are used, then the production process is simple, but the crystallinity of lithium metal composite oxide is insufficient
Solution Approach 1:
The invention changes the calcining parameters by introducing a gas mixture with specific composition (8-85 vol% moisture, 10-92 vol% oxygen, less than 4 vol% carbon oxide) and controlling the moisture amount (0.1-20 m3/kg relative to charged powder mass). This parameter optimization resolves the contradiction by achieving high crystallinity through controlled atmospheric conditions while maintaining a standard calcining process framework.
Solution Approach 2:
The invention applies preliminary action by pre-mixing the raw materials (metal composite compound and lithium compound) before calcining, and by preparing the gas mixture with controlled composition in advance. This ensures that when calcining occurs, the materials are already in optimal configuration and the atmosphere is properly prepared, leading to improved crystallinity without requiring complex in-process adjustments.
2Manufacturing precision
If calcining temperature is increased to improve crystallinity, then crystallinity improves, but energy consumption increases
Solution Approach 1:
The invention changes the approach from solely increasing temperature to optimizing the gas mixture composition and moisture content. By controlling moisture (8-85 vol%) and oxygen (10-92 vol%) levels, the process achieves high crystallinity at relatively lower temperatures (600-900°C), thereby reducing energy consumption while maintaining manufacturing precision.
3Manufacturing precision
If calcining time is extended to improve crystallinity, then crystallinity improves, but productivity decreases
Solution Approach 1:
The invention changes the approach from extending time to optimizing the chemical environment during calcining. By introducing a gas mixture with specific moisture (8-85 vol%) and oxygen (10-92 vol%) composition, the process achieves high crystallinity within 1-24 hours, balancing manufacturing precision with productivity through atmospheric control rather than time extension.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method results in lithium secondary batteries with high cycle retention rates, as demonstrated by a cycle retention rate of 90% or more, indicating improved battery performance and stability.
Implementation Method 1
a calcining step of introducing a gas mixture inside a calcining furnace and calcining a substance to be calcined in the calcining furnace at a temperature of higher than 600° C.
Implementation Method 2
calcining a substance to be calcined in the calcining furnace at a temperature of higher than 600° C.
Implementation Method 3
By improving crystallinity of lithium metal composite oxides, it can be expected to improve the cycle characteristics of lithium secondary batteries
Implementation Method 4
including a cooling step of cooling a calcined product inside the calcining furnace after the calcining step, in which a gas with a dew point of −15° C. or lower is supplied inside the calcining furnace in the cooling step
Data Source
AI summary
A method for producing a lithium metal composite oxide, including a calcining step of introducing a gas mixture inside a calcining furnace and calcining a substance to be calcined in the calcining furnace at a temperature of higher than 600° C., in which the substance to be calcined is a raw material mixture containing a mixture of a metal composite compound and a lithium compound or a reaction product of the metal composite compound and the lithium compound, the gas mixture before introduction contains oxygen, an amount of moisture in the gas mixture is 8 vol % or more and 85 vol % or less, and an amount of carbon dioxide in the gas mixture is less than 4 vol %.