High Nickel Cathode Material Stability via Particle Size Control
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Solution Overview
Problem
High nickel-based lithium composite oxides for lithium secondary batteries face challenges with mechanical and chemical stability, leading to particle breakage and deteriorated high temperature life-span characteristics and storage performance.
Innovation Solution
A cathode active material with a lithium metal oxide containing 80 mol% or more nickel, exhibiting a particle size distribution change rate and specific surface area change rate of 60% or less and 50% or less, respectively, after pressure-treating, which improves mechanical and chemical stability and high temperature performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high nickel content (80 mol% or more) is used in lithium metal oxide, then battery capacity is improved, but mechanical stability and chemical stability deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size distribution parameters (D10, D50, D90) and their change rates after pressure treatment. By optimizing these physical parameters within specific ranges, the cathode active material achieves both high capacity retention and improved stability, resolving the contradiction between high nickel content and stability
Solution Approach 2:
The patent creates a composite particle size distribution structure where particles with different size characteristics (D10, D50, D90) work together in a controlled ratio. This composite approach allows the material to maintain high capacity while improving mechanical stability through the synergistic effect of varied particle sizes
2Quantity of substance
If high nickel content is used in lithium metal oxide, then battery capacity is improved, but high temperature life-span characteristics deteriorate
Solution Approach 1:
The patent uses parameter changes by controlling the particle size distribution change rate to be within a specific range after pressure treatment. This parameter optimization prevents particle aggregation and maintains electrochemical activity at high temperatures, thereby improving life-span characteristics while preserving high capacity
3Quantity of substance
If high nickel content is used in lithium metal oxide, then battery capacity is improved, but storage performance and particle stability deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the D10, D50, and D90 particle size parameters and their change rates. By maintaining these parameters within optimal ranges, the material achieves high capacity while improving storage performance and particle stability, resolving the reliability contradiction
Data Source
AI summary
A cathode active material for a lithium secondary battery according to exemplary embodiments includes a lithium metal oxide containing 80 mol % or more of nickel of all elements except for lithium and oxygen, and has a particle size distribution change rate and a specific surface area change rate value satisfying a predetermined range.