Nickel Composite Hydroxide Crystallization for Battery Cathodes
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Solution Overview
Problem
Current methods for producing nickel composite hydroxide precursors for lithium-ion secondary batteries face challenges in achieving uniform particle size, high packing density, and maintaining sufficient contact with the electrolyte, leading to suboptimal battery capacity, output, and cycling characteristics.
Innovation Solution
A method involving a two-stage crystallization process without complex ion formation agents, where nickel salt and a neutralizer are continuously stirred in a reaction vessel, controlling the volume-average particle size ratio and pH to produce nickel composite hydroxide with spherical secondary particles, which are then calcined to form lithium nickel composite oxide with specific particle size and composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If particle size is increased to improve packing density and battery capacity, then battery capacity increases, but filter clogging occurs during cathode paste filtering
Solution Approach 1:
The patent applies local quality by creating a hierarchical particle structure where secondary particles (larger, 10-50 μm) provide high packing density for battery capacity, while being composed of primary particles (smaller, 0.1-1 μm) that prevent filter clogging. This multi-scale structure allows different regions of the particle system to serve different functions: larger particles for capacity and smaller particles for processability.
Solution Approach 2:
The patent implements the nested doll principle by forming secondary particles that are aggregates of multiple primary particles. The smaller primary particles (0.1-1 μm) are nested within and around larger secondary particle structures (10-50 μm), creating a fractal-like hierarchical arrangement that simultaneously achieves high packing density at the macro scale while maintaining fine particle characteristics at the micro scale to prevent filter clogging.
2Quantity of substance
If particle size is increased to improve packing density, then battery capacity increases, but coating defects occur during cathode paste application
Solution Approach 1:
The hierarchical particle structure with primary particles (0.1-1 μm) nested within secondary particles (10-50 μm) ensures that the fine primary particles fill voids and create a uniform paste consistency, enabling smooth coating without defects while the larger secondary particles provide the necessary packing density for high capacity.
3Reliability
If uniform particle size is achieved to improve battery characteristics, then cycling characteristics improve, but productivity decreases due to extended processing time
Solution Approach 1:
The patent segments the particle formation process into two distinct stages: primary particle formation (0.1-1 μm) followed by secondary particle aggregation (10-50 μm). This segmentation allows each stage to be optimized independently - primary particles form quickly with uniform size distribution for reliability, while secondary particles aggregate subsequently to achieve the desired size range without extending the critical primary formation time, thus maintaining productivity.
4Quantity of substance
If lithium cobalt composite oxide is used to achieve high voltage and energy density, then battery energy density increases, but material cost increases significantly
Solution Approach 1:
The patent replaces expensive cobalt-based materials with nickel-based composite hydroxide that can be produced cost-effectively through the described crystallization process. The uniform hierarchical particle structure ensures high performance comparable to cobalt-based materials, achieving the same energy density goals with more economical nickel-based chemistry.
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
This approach results in a nickel composite hydroxide with uniform particles and high packing density, enhancing battery capacity, output, and cycling characteristics, while maintaining productivity and reducing costs.
Implementation Method 1
a method involving a two-stage crystallization process without complex ion formation agents, where nickel salt and a neutralizer are continuously stirred in a reaction vessel
Implementation Method 2
which are then calcined to form lithium nickel composite oxide with specific particle size and composition
Data Source
AI summary
A nickel composite hydroxide having a volume-average particle size of the secondary particles of 8.0 μm to 50.0 μm is obtained, by obtaining a nickel composite hydroxide slurry in a primary crystallization process by providing an aqueous solution having at least a nickel salt and a neutralizer into a reaction vessel while continuously stirring in a state of not containing a complex ion formation agent, and controlling the crystallization reaction so that the ratio of the volume-average particles size of secondary particles with respect to that of the secondary particles finally obtained is 0.2 to 0.6, and producing the nickel composite hydroxide in a secondary crystallization process by continuing the crystallization process while keeping the amount of the obtained slurry constant, continuously removing only the liquid component of the slurry, and performing control so that the slurry has a temperature of 70° C. to 90° C. and a pH value at a standard liquid temperature of 25° C. of 10.0 to 11.0.