Single-Crystal Cathode Material With Uniform Particle Size
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Solution Overview
Problem
Existing lithium secondary batteries face challenges in achieving a uniform particle size distribution and high sharpness of particle size distribution in their positive electrode active materials, which affects the stability and efficiency of the batteries.
Innovation Solution
A single-crystal type positive electrode active material with a uniform particle size distribution is developed by inducing uniform particle growth 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
1Reliability
If harsh calcination conditions are used to induce single crystallization, then the stability of the positive electrode active material is improved, but the particle size distribution becomes non-uniform and agglomeration occurs
Solution Approach 1:
The patent applies parameter changes by precisely controlling calcination temperature (700-900°C), holding time (5-20 hours), and atmospheric conditions to achieve single crystallization. This resolves the contradiction by finding optimal parameters that promote crystal growth without causing excessive agglomeration, thereby maintaining both stability and particle size uniformity.
Solution Approach 2:
The patent uses preliminary action by preparing a uniformly mixed precursor with controlled particle size distribution before calcination. The precursor preparation includes thorough mixing of lithium source and transition metal sources, ensuring uniform composition that prevents agglomeration during subsequent calcination while still achieving single crystallization.
2Duration of action of stationary object
If the number of primary particles in secondary particles is reduced to improve stability, then lifetime characteristics are improved, but the manufacturing complexity increases
Solution Approach 1:
The patent applies the taking out principle by eliminating the disintegration step that was previously used to break down secondary particles into primary particles. Instead, the method directly produces single-crystal particles with controlled size distribution through optimized calcination, thereby achieving improved lifetime characteristics without increasing manufacturing complexity.
3Quantity of substance
If high nickel content is increased to maintain high reversible capacity, then discharge capacity is improved, but cation mixing increases and synthesis difficulty increases
Solution Approach 1:
The patent applies parameter changes by optimizing the nickel content range (0.8-0.95) and controlling calcination parameters (temperature 700-900°C, time 5-20 hours, atmosphere) to suppress cation mixing. This enables synthesis of high-nickel materials with high reversible capacity while maintaining ease of manufacture through controlled single crystallization that prevents phase segregation and cation disordering.
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 resulting positive electrode active material exhibits improved capacity and lifetime characteristics in lithium secondary batteries, with a more uniform and sharp particle size distribution.
Implementation Method 1
a lithium composite oxide capable of intercalation/deintercalation of lithium
Implementation Method 2
materials capable of undergoing electrochemical reactions at a positive electrode and a negative electrode
Implementation Method 3
the stability (lifetime characteristics, and the like) of the positive electrode active material can be improved as the number of primary particles constituting the secondary particles decreases
Data Source
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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 which has a uniform particle size distribution and high sharpness of the particle size distribution, and a lithium secondary battery including the same.