Single-Particle Cathode Material for High Rolling Density
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Solution Overview
Problem
Conventional high-Ni-based positive electrode active materials with uniform particle diameters result in low density and difficulty achieving high energy density due to increased porosity during the manufacturing process.
Innovation Solution
A positive electrode active material in the form of a single particle with a specific particle size distribution, characterized by a skewness of 0.03 to 0.04, achieves a high rolling density and reduces porosity, enhancing the contact area with conductive agents and improving charging capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If uniform particle diameter is used in high-Ni-based positive electrode active material, then manufacturing consistency is improved, but rolling density decreases and energy density cannot be achieved
Solution Approach 1:
The invention changes the particle size distribution parameters by controlling the D90/D10 ratio to be 2.0 or less and setting D50 within 3-10 μm. This parameter optimization allows particles to pack more efficiently during rolling, achieving high rolling density (3.57 g/cm³ or more) while maintaining manufacturing consistency through controlled distribution rather than uniform size.
2Quantity of substance
If particle size distribution is optimized for high rolling density, then energy density is improved, but contact area with conductive agents may be reduced
Solution Approach 1:
The invention applies local quality by ensuring that particles within the optimized size range (D50: 3-10 μm, D90/D10 ≤ 2.0) maintain appropriate surface properties and morphology. This allows different regions of the electrode to have optimal characteristics: particles pack densely for high energy density while their surfaces maintain sufficient contact area with conductive agents for good electrical conductivity.
Data Source
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AI summary
The present invention relates to a positive electrode active material comprising a lithium composite transition metal oxide in the form of a single particle containing two or more types selected from nickel, cobalt, and manganese, wherein the lithium composite transition metal oxide has a particle size distribution that satisfies equation 1 below. In equation 1, skewness is a value calculated according to equation 2 below, and mode is a particle size value when the y value is the maximum in a particle size distribution curve where the x-axis is a particle size (unit: µm) of the lithium composite transition metal oxide and the y-axis is a volume percentage (unit: %).