Single-Crystal Cathode Material With Uniform Particle Growth
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Solution Overview
Problem
Existing lithium secondary batteries face challenges in achieving uniform particle growth and reducing inter-particle agglomeration of positive electrode active materials, leading to increased costs and potential surface damage during processing.
Innovation Solution
A single-crystal type positive electrode active material is developed, characterized by a uniform particle size distribution and high sharpness of the particle size distribution, achieved through uniform particle growth induced without harsh calcination conditions and a disintegration process, using a combination of a molten salt-based flux and a metal oxide-based dopant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If harsh calcination conditions are used to achieve single-crystal structure, then particle growth is improved, but inter-particle agglomeration increases and surface damage occurs
Solution Approach 1:
The patent modifies calcination parameters by using a two-stage process: first stage at 900-950°C for 5-10 hours to form precursor, second stage at 600-700°C for 5-10 hours to achieve single-crystal structure. This parameter optimization prevents agglomeration and surface damage while maintaining particle size distribution uniformity with D50 of 3-9 μm and narrow distribution width.
Solution Approach 2:
The patent performs preliminary particle size control during precursor formation at 900-950°C before the final single-crystal calcination. This preliminary action establishes uniform particle growth and prevents subsequent agglomeration during the lower-temperature single-crystal formation stage, eliminating the need for disintegration processes.
2Manufacturing precision
If disintegration process is used to reduce primary particle number, then single-crystal structure is achieved, but processing cost increases and surface damage occurs
Solution Approach 1:
The patent performs preliminary particle size control during precursor formation at 900-950°C before the final single-crystal calcination. This preliminary action establishes uniform particle growth and prevents subsequent agglomeration during the lower-temperature single-crystal formation stage, eliminating the need for disintegration processes.
Solution Approach 2:
Instead of forming secondary particles and then disintegrating them to achieve single-crystal structure, the patent inverts the approach by directly forming single-crystal particles through optimized two-stage calcination. This eliminates the disintegration step entirely, reducing processing costs and avoiding surface damage.
3Quantity of substance
If nickel content is increased to improve discharge capacity, then reversible capacity increases, but cation mixing increases and synthesis difficulty increases
Solution Approach 1:
The patent optimizes calcination parameters (temperature 600-700°C, time 5-10 hours, oxygen atmosphere) to enable successful synthesis of high-nickel content lithium composite oxide with reduced cation mixing. The two-stage process with controlled parameters makes synthesis of high-capacity materials feasible while maintaining structural integrity.
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 solution results in improved capacity and lifetime characteristics of lithium secondary batteries, with a peak of the particle size distribution shifted toward the maximum particle size and high sharpness of the peak, reducing processing costs and enhancing battery performance.
Implementation Method 1
a single-crystal type positive electrode active material in which the peak of the particle size distribution observed in the volume cumulative particle size distribution graph is shifted toward Dmax, which is the maximum particle size, and the sharpness of the peak of the particle size distribution is high
Data Source
AI summary
The present invention relates to a positive electrode active material and a lithium secondary battery including the same, and more particularly, to a single-crystal type positive electrode active material in which the peak of the particle size distribution observed in the volume cumulative particle size distribution graph is shifted toward Dmax, which is the maximum particle size, and the sharpness of the peak of the particle size distribution is high, and a lithium secondary battery including the same.