Mixed-Circularity Cathode Material for Stable High-Nickel Batteries
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Solution Overview
Problem
High nickel-based lithium oxide cathode materials suffer from reduced life-span and operational stability due to cation disorder and structural instability, which affects the performance and capacity retention of lithium secondary batteries.
Innovation Solution
A cathode active material comprising a mixture of first and second lithium metal oxide particles with different circularities, where the first has a circularity of 0.9 to 0.96 and the second has a smaller circularity, is used to enhance structural stability and packing density, incorporating polycrystalline and single crystal structures to improve mechanical and electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high nickel content is used to increase battery capacity, then energy density is improved, but cation disorder occurs causing reduced life-span and operational stability
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the central core region contains high nickel content (0.8-0.95) for high capacity, while the outer shell region has reduced nickel content (0.6-0.8) to prevent cation disorder and structural degradation. This spatial differentiation of nickel concentration allows the battery to achieve high energy density while maintaining operational stability and long cycle life.
2Quantity of substance
If high nickel content is used to increase battery capacity, then energy density is improved, but structural instability occurs affecting capacity retention
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the central core region contains high nickel content (0.8-0.95) for high capacity, while the outer shell region has reduced nickel content (0.6-0.8) to prevent cation disorder and structural degradation. This spatial differentiation of nickel concentration allows the battery to achieve high energy density while maintaining operational stability and long cycle life.
Solution Approach 2:
The patent applies composite materials by combining regions with different nickel concentrations within a single cathode particle. The core-shell structure creates a composite architecture where the high-nickel core provides capacity and the low-nickel shell provides structural stability, effectively combining the advantages of both high-capacity and stable materials.
3Volume of stationary object
If cathode active material particles are made more spherical to improve packing density, then electrode density is improved, but capacity retention may be affected
Solution Approach 1:
The patent applies parameter changes by optimizing the circularity parameter of cathode particles to a specific range (0.85-0.95). This controlled sphericity improvement enhances packing density and electrode density while the patent simultaneously controls particle size (5-20 μm) to maintain capacity retention, demonstrating how parameter optimization can balance multiple performance requirements.
Data Source
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AI summary
A cathode active material for lithium secondary batteries according to embodiments of the present invention includes different types of lithium metal oxide particles having different circularities in a predetermined mixing weight ratio. When using the cathode active material for a lithium secondary battery, it is possible to provide a secondary battery having enhanced mechanical and electrical stability, and improved energy density.