Lithium-Titanium Composite Oxide Particle Size Control for Higher Capacity
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Solution Overview
Problem
Lithium-titanium complex oxides, particularly spinel-type lithium titanate, face limitations in high capacity, low energy density, and low reaction rates due to their small volume change and partial formation in a rock salt structure, leading to decreased effective capacity and electrochemical activity.
Innovation Solution
A preparation method involving the mixing of titanium oxide, lithium compound, and zirconium compound, followed by wet-milling to achieve specific particle sizes, spray drying, and calcination to enhance specific surface area and electrochemical characteristics, including controlling particle sizes through wet-milling and calcination conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If spinel-type lithium titanate is used as electrode material, then volume change during charging and discharging is small and lifetime is long, but capacity per unit weight is small and energy density is low
Solution Approach 1:
The patent changes the particle size parameter of lithium titanate to sub-micron range (0.1-1.0 μm) through wet milling process, which increases the specific surface area and improves electrochemical activity while maintaining the stable spinel structure. This parameter change enables both small volume change during cycling and improved capacity per unit weight.
2Reliability
If spinel-type lithium titanate is used, then electrochemical activity is present, but reaction rate is low and effective capacity is decreased
Solution Approach 1:
The patent segments the lithium titanate particles into fine sub-micron sizes through wet milling, creating numerous small particles with high specific surface area. This segmentation increases the number of active sites available for electrochemical reactions and improves ion transport kinetics, thereby enhancing both electrochemical activity and reaction rate.
Solution Approach 2:
The patent changes the particle size parameter to sub-micron range (0.1-1.0 μm) which fundamentally alters the surface-to-volume ratio. This parameter change enables faster ion diffusion and electron transport, improving the reaction rate while preserving the electrochemical activity of the spinel structure.
3Ease of manufacture
If conventional solid-state mixing and calcination is used, then manufacturing process is simple, but particle size is large and specific surface area is small
Solution Approach 1:
The patent introduces a liquid medium (water or alcohol) as an intermediary during the mixing and milling process. This liquid medium enables effective wet milling of particles to sub-micron sizes and facilitates uniform dispersion of precursors before calcination, achieving high specific surface area while maintaining process simplicity.
Solution Approach 2:
The patent replaces conventional dry mechanical mixing with wet milling using a colloid mill or sand mill. This mechanical system substitution enables much finer particle size reduction to sub-micron range while maintaining ease of manufacture through a continuous liquid-phase processing approach.
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 improves the specific surface area, tap density, and electrochemical characteristics of lithium-titanium complex oxides, addressing the limitations of existing materials by optimizing particle size and structure, resulting in enhanced performance.
Implementation Method 1
wet-milling the mixture using beads having a size of 0.10 to 0.30 mm to obtain a wet-milled mixture
Implementation Method 2
wet-milling the slurry mixture for 2 to 7 hours to the slurry mixture having a particle size D50 of 0.10 μm
Implementation Method 3
spray drying the wet-milled mixture to obtain a spray dried mixture
Implementation Method 4
calcining the spray dried mixture
Data Source
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AI summary
The present invention relates to a lithium-titanium complex oxide used in an electrode active material. A preparation method of a lithium-titanium complex oxide according to the present invention comprises the steps of: preparing a slurry mixture in which a titanium oxide, lithium and zirconium are mixed; wet-milling the mixture using beads having a size of 0.30 mm or less to obtain a wet-milled mixture; spray drying the wet-milled mixture to obtain a spray dried mixture; and calcining the spray dried mixture. The preparation method according to the present invention has an effect that the particle sizes can be adjusted through the milling process by controlling particle sizes of the precursor slurry through wet-milling.