Nickel-Manganese Hydroxide Porosity for High-Density Battery Cathodes
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Solution Overview
Problem
Current methods for producing positive electrode active materials for nonaqueous electrolyte secondary batteries fail to achieve a balance between high volume energy density and sufficient output characteristics, and there is a lack of efficient industrial-scale production methods for nickel-manganese composite hydroxides that can enhance battery performance.
Innovation Solution
A nickel-manganese composite hydroxide with specific chemical composition and structural properties, represented by General Formula NixMnyMz(OH)2+α, is produced using a crystallization process that adjusts dissolved oxygen, nickel concentrations, and stirring power, resulting in a material with controlled particle size distribution, sparsity/density, and tap density, which is then used to create a lithium-nickel-manganese composite oxide with improved battery characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the open pore ratio is increased to improve battery characteristics, then battery characteristics are improved, but volume energy density decreases
Solution Approach 1:
The patent applies porous materials by controlling the open pore ratio of the hydroxide precursor within specific ranges (5-30% in some embodiments, 10-20% in others). This porous structure facilitates electrolyte penetration and lithium ion diffusion, improving battery characteristics while maintaining reasonable volume energy density through optimized pore architecture rather than excessive porosity.
Solution Approach 2:
The patent employs parameter changes by precisely controlling multiple parameters including open pore ratio, particle size distribution, tap density, and crystallite size during the hydroxide synthesis process. By adjusting these parameters within specific ranges and their interrelationships, the patent achieves optimal balance between battery performance and volume energy density.
2Reliability
If hydroxide is crushed and granulated again to obtain precursor with desired void rate and high open pore ratio, then battery characteristics are improved, but productivity decreases
Solution Approach 1:
The patent applies preliminary action by controlling the particle morphology, size distribution, and pore structure during the initial hydroxide synthesis process itself, rather than requiring subsequent crushing and granulation steps. The hydroxide is synthesized directly with desired characteristics including specific open pore ratio and particle properties, eliminating redundant processing steps and improving productivity.
Solution Approach 2:
The patent implements continuity of useful action by integrating the formation of desired particle characteristics and pore structure into the continuous hydroxide synthesis process. This eliminates discontinuous intermediate steps like crushing and re-granulation, maintaining continuous production flow and improving overall productivity while achieving the required precursor properties.
3Reliability
If uniform particle size distribution is achieved to improve cycle characteristics and output, then high capacity and long life are obtained, but fillability of positive electrode active material decreases
Solution Approach 1:
The patent applies local quality by implementing a controlled particle size distribution rather than complete uniformity. Specific particle size ranges are targeted (e.g., D50 between 5-20 μm, with specific D10-D90 ranges) to provide local optimization where smaller particles fill gaps between larger particles, improving both fillability and maintaining cycle characteristics through appropriate size distribution.
Solution Approach 2:
The patent resolves the contradiction by transitioning from considering only particle size uniformity to a multi-dimensional approach that includes particle size distribution shape, particle morphology, density, and pore structure. By controlling particles in multiple dimensions (size, shape, density, porosity), the patent achieves both good fillability and cycle characteristics.
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 approach enables the production of nonaqueous electrolyte secondary batteries with high energy density and output characteristics, while also facilitating easy industrial-scale production of the nickel-manganese composite hydroxide, leading to enhanced battery performance and cost-effectiveness.
Implementation Method 1
a crystallization process that adjusts dissolved oxygen, nickel concentrations, and stirring power
Implementation Method 2
a crystallization process that adjusts dissolved oxygen, nickel concentrations, and stirring power, resulting in a material with controlled particle size distribution
Implementation Method 3
a crystallization process that adjusts dissolved oxygen, nickel concentrations, and stirring power
Implementation Method 4
a material with controlled particle size distribution, sparsity/density, and tap density
Data Source
AI summary
Provided are a positive electrode active material with which a nonaqueous electrolyte secondary battery having a high energy density can be obtained, a nickel-manganese composite hydroxide suitable as a precursor of the positive electrode active material, and production methods capable of easily producing these in an industrial scale. Provided is a nickel-manganese composite hydroxide represented by General Formula (1): NixMnyMz(OH)2+α and containing a secondary particle formed of a plurality of flocculated primary particles. The nickel-manganese composite hydroxide has a half width of a diffraction peak of a (001) plane obtained by X-ray diffraction measurement of at least 0.10° and up to 0.40° and has a degree of sparsity/density represented by [(void area within secondary particle/cross section of secondary particle)×100](%) of at least 0.5% and up to 10%. Also provided is a production method of the nickel-manganese composite hydroxide.