Positive Electrode Active Material Dispersion for Crack-Resistant Output
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing positive electrode active materials for nonaqueous electrolyte secondary batteries face challenges in achieving high output characteristics and durability due to particle cracking and sintering issues during electrode formation and charge/discharge cycles, particularly in large-sized power applications like electric vehicles.
Innovation Solution
A method involving the production of nickel-containing composite oxide particles with a specific particle size distribution, followed by heat treatment and dry dispersion to create lithium-transition metal composite oxide particles with a uniform particle size and reduced grain boundaries, enhancing the material's durability and output characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If secondary particles are formed by aggregating a large number of primary particles to increase BET specific surface area, then output characteristics are improved, but cracks occur in secondary particles during pressurization and charge/discharge cycles, reducing durability
Solution Approach 1:
The invention divides the secondary particle into multiple primary particles (3-10 primary particles per secondary particle) with controlled aggregation. This segmentation allows the secondary particle to maintain sufficient surface area for high output while reducing internal stress concentration that causes cracking, thereby improving durability without sacrificing power characteristics.
2Power
If particle size of secondary particles is reduced to improve output characteristics, then BET specific surface area increases, but particle cracking occurs during electrode formation, reducing durability
Solution Approach 1:
The invention optimizes the particle size parameters by controlling the 1D90/1D10 ratio to 3 or less and setting 2D50/2DSEM to 1-4. These parameter changes ensure that secondary particles are small enough to provide high surface area for output while being large enough to resist cracking during electrode formation and charge/discharge cycles.
3Productivity
If heat treatment is performed to sinter particles and improve density, then manufacturing efficiency is improved, but particle size distribution becomes uneven and grain boundaries increase, reducing durability
Solution Approach 1:
The invention precisely controls heat treatment parameters including temperature (900-1100°C), time (5-20 hours), and atmosphere (oxygen flow rate 5-20 L/min). These parameter changes enable sufficient sintering for manufacturing efficiency while preventing excessive grain growth and maintaining uniform particle size distribution, thus avoiding increased grain boundaries that would reduce durability.
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 method efficiently produces lithium-transition metal composite oxide particles with improved durability and output characteristics, reducing particle cracking and sintering issues, while maintaining electrode filling performance and charge/discharge efficiency.
Implementation Method 1
subjecting the raw material mixture to a heat treatment to obtain a heat-treated material
Implementation Method 2
subjecting the heat-treated material to a dispersion treatment by a dry process to obtain a first dispersion
Data Source
AI summary
A method of producing a positive electrode active material for a nonaqueous electrolyte secondary battery, the method includes preparing nickel-containing composite oxide particles having a ratio 1D90/1D10 of a 90% particle size 1D90 to a 10% particle size 1D10 in volume-based cumulative particle size distribution of 3 or less; obtaining a raw material mixture containing the composite oxide particles and a lithium compound and having a ratio of a total number of moles of lithium to a total number of moles of metal elements contained in the composite oxide in a range of 1 to 1.3; subjecting the raw material mixture to a heat treatment to obtain a heat-treated material; subjecting the heat-treated material to a dry-dispersion treatment to obtain a first dispersion; and bringing the first dispersion into contact with a liquid medium to obtain a second dispersion.