MO-LTO Core-Shell Particles for Battery Output
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Solution Overview
Problem
Lithium titanium oxide (LTO) negative electrode materials face issues with volumetric swelling, conductivity degradation, and non-uniform particle shape, leading to poor electroconductivity and capacity in lithium secondary batteries, requiring a solution that enhances electroconductivity and output characteristics while minimizing gas generation.
Innovation Solution
The development of metal oxide-lithium titanium oxide (MO-LTO) composite particles with a core-shell structure, where primary particles of LTO are coated with a metal oxide such as Al2O3 or ZrO2, forming secondary particles with a specific size distribution and porous structure to improve electroconductivity and reduce gas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If LTO particles are prepared to have a small particle size less than 1 μm to increase charging rate, then high rate charge/discharge is enabled, but specific surface area increases requiring large amount of binder and dispersion becomes difficult
Solution Approach 1:
The patent applies the nesting principle by forming secondary particles through aggregation of primary LTO particles. The primary particles (less than 1 μm) are nested within clusters to form secondary particles with controlled size distribution, thereby reducing the effective specific surface area while preserving the high charging rate benefits of small primary particles
Solution Approach 2:
The patent changes the particle size parameter by creating a bimodal distribution with primary particles less than 1 μm for high rate performance and secondary particles with controlled larger size to reduce specific surface area. This parameter transformation resolves the contradiction between charging rate and specific surface area
2Reliability
If lithium metal oxide is used as negative electrode material to achieve high charging rate, then excellent life characteristics and safety are obtained, but electroconductivity and capacity are lower compared to carbonaceous material
Solution Approach 1:
The patent employs composite materials by combining LTO with carbonaceous materials in a core-shell or mixed structure. The LTO component provides reliability and safety, while the carbonaceous material component enhances electroconductivity and capacity, thereby resolving the contradiction between reliability and power
3Device complexity
If non-uniform particle shape of lithium metal oxide is used, then material structure is simple, but homogeneous mixing with binder and conductive material becomes difficult during electrode manufacture
Solution Approach 1:
The patent applies local quality by creating core-shell structures where the LTO core maintains structural simplicity while the shell layer (carbonaceous material or conductive coating) provides uniform surface properties that enable homogeneous mixing with binder and conductive materials during electrode manufacture
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 MO-LTO composite particles demonstrate reduced gas generation, decreased internal resistance, and enhanced electroconductivity, resulting in improved output characteristics and extended battery life.
Implementation Method 1
primary particles of LTO are coated with a metal oxide such as Al2O3 or ZrO2, forming secondary particles
Implementation Method 2
forming secondary particles with a specific size distribution and porous structure
Implementation Method 3
the diffusion rate of lithium ions in an active material is low
Data Source
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AI summary
The present disclosure relates to a negative electrode active material having excellent output characteristics and causing little gas generation, and an electrode including the negative electrode active material. The negative electrode active material includes metal oxide-lithium titanium oxide (MO-LTO) composite particles which have a shape of secondary particles formed by aggregation of primary particles, wherein the primary particles have a core-shell structure including a core and a shell totally or at least partially covering the surface of the core, the core includes primary particles of lithium titanium oxide (LTO), and the shell includes a metal oxide.