Lithium Titanium Oxide Electrode Tap Density via Mechano-Chemical Synthesis
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Solution Overview
Problem
Current methods for preparing negative active materials for lithium batteries, such as lithium titanium oxides, face challenges with low tap density, high particle diameter, and energy density per volume, which affect the electrochemical reactivity and performance of lithium titanium oxide electrodes.
Innovation Solution
A mechano-chemical treatment method is used to mix a titanium source with a lithium source, followed by heat treatment at a controlled temperature, resulting in lithium titanium oxide with a high tap density and nano-sized particle diameter, enhancing electrochemical reactivity and energy density per volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solid-phase method is used to prepare lithium titanium oxide, then manufacturing cost is reduced, but particle diameter increases and physical properties deteriorate
Solution Approach 1:
The patent applies preliminary action by conducting ball-milling treatment before heat treatment to pre-form fine particles. This preliminary mechanical activation ensures that even after heat treatment, the particles maintain small diameters (0.1-10 μm) without requiring excessive heat treatment temperatures that would increase manufacturing costs.
Solution Approach 2:
The patent changes the parameters of heat treatment temperature and time to optimize particle diameter. By controlling heat treatment temperature at 500-900°C for 1-48 hours, the method achieves fine particle size while maintaining the cost-effective solid-phase process.
2Manufacturing precision
If heat treatment is performed at low temperature, then particle diameter is reduced, but unreacted titanium dioxide remains
Solution Approach 1:
Ball-milling treatment is performed as a preliminary action before heat treatment to thoroughly mix reactants and create fine particle precursors. This ensures that even at lower heat treatment temperatures (500-900°C), the reaction proceeds to completion without leaving unreacted titanium dioxide, while maintaining small particle diameters.
Solution Approach 2:
The patent replaces purely thermal processing with a combination of mechanical ball-milling and controlled heat treatment. The mechanical energy from ball-milling activates the reactants, allowing complete reaction at lower temperatures that would otherwise require excessive heat treatment.
3Reliability
If heat treatment is performed at high temperature, then reaction completeness improves, but particle diameter increases and physical properties deteriorate
Solution Approach 1:
Ball-milling treatment is performed before heat treatment to pre-form fine particle precursors with large surface area and good contact between reactants. This preliminary mechanical activation allows complete reaction to occur at moderate temperatures (500-900°C) without requiring high temperatures that would cause particle growth.
Solution Approach 2:
The patent optimizes the parameter combination of heat treatment temperature (500-900°C) and time (1-48 hours) to achieve complete reaction while limiting particle growth. The extended time at moderate temperature replaces the need for high temperature, maintaining fine particle size.
4Area of stationary object
If porous agglomeration structure is formed, then surface area increases, but density decreases and energy density per volume decreases
Solution Approach 1:
The patent controls the parameters of heat treatment temperature and time to achieve a balanced structure. By limiting heat treatment temperature to 500-900°C and time to 1-48 hours, the method produces particles with controlled porosity that maintain high density (0.8-2.0 g/cm³) while retaining sufficient surface area for electrochemical activity.
Solution Approach 2:
The patent creates a composite structure where lithium titanium oxide forms a dense matrix with controlled porosity. This composite architecture provides both the high surface area needed for electrochemical reactivity and the high density required for energy density per volume.
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 produces lithium titanium oxide with high crystallinity and tap density, leading to improved electrochemical reactivity and energy density per volume, suitable for high-performance lithium batteries.
Implementation Method 1
A mechano-chemical treatment method is used to mix a titanium source with a lithium source
Implementation Method 2
followed by heat treatment at a controlled temperature, resulting in lithium titanium oxide with a high tap density and nano-sized particle diameter
Implementation Method 3
The method produces lithium titanium oxide with high crystallinity and tap density
Data Source
AI summary
A negative active material for a rechargeable lithium battery, a method of preparing the negative active material, and a rechargeable lithium battery including the negative active material. The negative active material for a rechargeable lithium battery includes lithium titanium oxide (Li4Ti5O12) having a tap density of about 1.2 g/cc to 2.2 g/cc. The lithium titanium oxide is prepared by a mechano-chemical treatment and a heat treatment at a low temperature of about 650° C. to 775° C. According to the present invention, lithium titanium oxide having high crystallinity and tap density can be prepared through a simple and low-cost solid-phase method, e.g., a mechano-chemical treatment, and thus an electrode with excellent electrochemical reactivity and high energy density per volume can be fabricated.