Porous Lithium-Titanium Oxide for Faster Li-Ion Diffusion
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Solution Overview
Problem
Conventional lithium-titanium complex oxides face challenges with low capacity, low energy density, and poor rate performance, making them unsuitable for high-power applications, while existing preparation methods result in materials with low specific surface area and high internal resistance.
Innovation Solution
A novel preparation method involving the addition of a pore-inducing material during wet-milling to control particle sizes, incorporating a controlled amount of rutile-type titanium oxide and zirconium, followed by spray drying and calcination, results in lithium-titanium complex oxide with optimized porosity and particle size, enhancing electrical conductivity and reducing internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional preparation methods are used to produce lithium-titanium complex oxide, then the material can be obtained with relatively low specific surface area (10 m²), but the internal resistance is high and electrical conductivity is poor
Solution Approach 1:
The invention changes the particle size parameter by controlling the wet-milling process to achieve a specific surface area of 10 m² or more, which directly improves electrical conductivity and reduces internal resistance of the lithium-titanium complex oxide material
Solution Approach 2:
The invention segments the material into finer particles through controlled wet-milling, creating a distribution of primary particles (0.03-0.2 μm) and secondary particles (5-20 μm) that increases specific surface area while maintaining good packing density and reducing internal resistance
2Reliability
If lithium-titanium complex oxide is used as anode active material, then excellent cycle characteristics are achieved due to high oxidation/reduction potential (1.5 V), but capacity per unit weight and energy density are low
Solution Approach 1:
The invention creates local quality variations by forming a composite structure with pores distributed throughout the particle interior, where the pore regions facilitate faster lithium ion diffusion while the solid regions maintain structural stability, achieving both high capacity and excellent cycle characteristics
Solution Approach 2:
The invention introduces a porous structure with controlled pore volume (0.03-0.15 mL/g) and pore size (0.003-0.015 μm) that increases the effective surface area for lithium ion insertion/extraction, thereby improving capacity per unit weight while maintaining the structural integrity needed for excellent cycle characteristics
3Ease of manufacture
If particle sizes are not controlled in the preparation process, then the production process is simpler, but the diffusion rate of lithium ions and electron transport are poor
Solution Approach 1:
The invention performs preliminary particle size control during the wet-milling process by adding pore-forming agents and controlling milling parameters, so that the desired particle size distribution (primary particles 0.03-0.2 μm, secondary particles 5-20 μm) is achieved before calcination, ensuring fast lithium ion diffusion without complicating the overall process
Solution Approach 2:
The invention changes the particle size parameters through controlled wet-milling to achieve optimal diffusion characteristics, where the specific surface area is increased to 10 m² or more and pore volume is controlled at 0.03-0.15 mL/g, enabling fast lithium ion diffusion and electron transport
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 complex oxide with improved charge and discharge characteristics, increased diffusion rates of lithium ions, and enhanced electron transport, leading to better output characteristics suitable for high-power applications.
Implementation Method 1
adding a pore inducing material for forming appropriate pores within particles
Implementation Method 2
adjusting sizes of primary particles of the lithium-titanium complex oxide
Implementation Method 3
spray drying and calcination
Implementation Method 4
calcining the mixture at 800 °C or more in an oxygen atmosphere
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
The present invention relates to a lithium-titanium complex oxide, a preparation method thereof, and a lithium secondary battery comprising the same and, more specifically, to a lithium-titanium complex oxide which maintains appropriate pores within particles, and which is prepared by adding a pore inducing material in the wet-milling step to adjust sizes of primary particles of the lithium-titanium complex oxide, a preparation method thereof, and a lithium secondary battery comprising the same. Since a lithium-titanium complex oxide having reduced sizes of primary particles, the lithium-titanium complex oxide according to the present invention shortens a moving distance of lithium ions by adding the pore inducing material, diffusion rate of the lithium ions is increased. Thereby, a battery comprising the lithium-titanium complex oxide according to the present invention exhibits excellent output characteristics by having a structure favorable to electron transport.