Nickel Composite Oxide Particle Segmentation for Battery Durability
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 secondary particles into smaller secondary particles, each composed of a reduced number of primary particles (5-50 primary particles per secondary particle). This segmentation reduces the size of secondary particles while maintaining the aggregated structure, thereby reducing internal stress and crack formation during charge/discharge cycles, improving durability while preserving output characteristics through controlled surface area.
Solution Approach 2:
The invention changes the particle size parameters by controlling the 50% particle size (2D50) to be 3 μm or less and the 90% particle size (2D90) to be 10 μm or less. These parameter changes optimize the balance between surface area for high output and particle integrity for durability, preventing crack formation while maintaining high BET specific surface area.
2Reliability
If particle size of secondary particles is reduced to improve durability, then crack resistance is improved, but BET specific surface area decreases, reducing output characteristics
Solution Approach 1:
The invention segments the particle population into two distinct size ranges: small secondary particles (2D50 ≤ 3 μm, 2D90 ≤ 10 μm) for durability, and controls the particle size distribution to maintain adequate surface area. The segmented structure with reduced primary particle aggregation (5-50 primary particles per secondary particle) ensures both crack resistance and sufficient BET specific surface area for high output characteristics.
3Reliability
If lithium-transition metal oxide particles are produced with single particle structure to eliminate cracks, then durability is improved, but manufacturing complexity increases due to additional heat treatment steps
Solution Approach 1:
The invention performs preliminary action by controlling the particle size and structure of secondary particles before electrode formation. By pre-establishing the optimal particle size distribution (2D50 ≤ 3 μm, 2D90 ≤ 10 μm) and aggregation structure (5-50 primary particles per secondary particle), the material inherently resists crack formation during subsequent pressurization and charge/discharge cycles, eliminating the need for additional post-processing heat treatment steps to prevent cracking.
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 by reducing particle cracking and sintering, leading to better capacity retention and power density while maintaining electrode filling performance.
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.