Lithium Titanium Composite Oxide Negative Electrode Pore Volume Maintenance
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Solution Overview
Problem
Lithium titanium composite oxide negative electrode active materials face challenges in maintaining adequate pore volume during the rolling process, leading to reduced charge rate capability due to difficulty in lithium diffusion.
Innovation Solution
Introducing a metallic element to control the particle diameter of primary particles, ensuring the strength and pore volume of secondary particles, thereby maintaining adequate pore volume during rolling without a separate grinding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the lithium titanium composite oxide is used as a negative electrode active material, then fast charge performance and low-temperature performance are improved, but charge rate capability is reduced due to pore collapse during rolling
Solution Approach 1:
The patent changes the physical parameters of the lithium titanium composite oxide by controlling the primary particle diameter to 0.5 μm or less and the secondary particle diameter to 1-30 μm with specific porosity (0.3-0.6). This parameter optimization prevents pore collapse during rolling while maintaining fast charge performance and lithium diffusion capability.
Solution Approach 2:
The patent segments the lithium titanium composite oxide into a hierarchical structure with primary particles (0.5 μm or less) agglomerated into secondary particles (1-30 μm). This segmentation maintains porosity at the primary particle level while providing structural integrity at the secondary particle level, preventing complete pore collapse during electrode rolling.
2Reliability
If the particle diameter of primary particles is reduced to maintain pore volume, then lithium diffusion is improved, but particle strength decreases
Solution Approach 1:
The patent employs a nested structure where small primary particles (0.5 μm or less) containing pores are nested within larger secondary particles (1-30 μm). The primary particles maintain porosity for lithium diffusion, while the secondary particles provide mechanical strength. The nested arrangement allows small particles to be protected within a stronger outer structure.
Solution Approach 2:
The patent creates a composite particle structure combining primary particles with specific porosity and secondary particles with mechanical strength. The composite structure integrates the advantages of small particles (high surface area, good diffusion) with the advantages of larger aggregated structures (mechanical integrity, pore maintenance during processing).
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 allows for improved lithium diffusion and excellent rate capability by maintaining a significant pore volume and particle shape, even under pressure, enhancing the performance of lithium secondary batteries.
Implementation Method 1
lithium diffusion is difficult in the active material layer
Data Source
Figure 1~2
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AI summary
The present invention relates to an active material for a lithium secondary battery, which includes a secondary particle formed by agglomeration of primary particles which include a lithium titanium composite oxide represented by Formula 1 or Formula 2, wherein a pore volume is in a range of 0.001 cm3/g to 0.05 cm3/g, and a method of preparing the same, wherein the active material for a lithium secondary battery according to the present invention may maintain an adequate pore volume even during rolling, because strength of the secondary particle is improved by controlling a particle diameter of the primary particle by introducing a metallic element. Also, the method of preparing the active material for a lithium secondary battery according to the present invention is suitable for the preparation of an active material for a lithium secondary battery, because the particle diameter of the primary particle may be controlled by adjusting an amount of the metallic element introduced, and through this, the strength of the secondary particle may be improved and the pore volume during the rolling may be maintained.