Hollow Lithium Nickel Composite Oxide Cathode for High Energy Density
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current lithium-ion secondary batteries face challenges in achieving high energy density, uniform particle size distribution, and specific surface area, leading to issues with battery capacity, cycling characteristics, and reaction resistance, particularly due to the lack of a suitable production method for lithium composite oxides with a uniform and suitable particle size.
Innovation Solution
A method for producing nickel composite hydroxide with a controlled particle size distribution, involving a nucleation and particle growth process, and subsequent calcination to form lithium nickel composite oxide with a hollow structure, which enhances the cathode active material's performance by achieving a uniform particle size and high specific surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If cathode active material with large particle size is used, then packing density is improved, but surface area for reacting with electrolyte decreases and reaction resistance increases
Solution Approach 1:
The cathode active material is divided into multiple primary particles (0.5-5 μm) that aggregate to form secondary particles (5-20 μm). This segmentation allows the material to have small primary particle sizes for high surface area and reaction activity, while forming larger secondary particles for improved packing density. The hierarchical structure resolves the contradiction between surface area and packing density.
2Area of stationary object
If cathode active material with small particle size is used, then surface area for reacting with electrolyte is improved, but packing density decreases
Solution Approach 1:
Multiple primary particles are nested together to form secondary particles, creating a hierarchical structure. The primary particles (0.5-5 μm) provide high surface area, while their aggregation into secondary particles (5-20 μm) improves packing density. This nested structure allows small particles to be contained within larger particle frameworks, resolving the contradiction between surface area and packing density.
3Adaptability or versatility
If cathode active material with wide particle size distribution is used, then production flexibility is improved, but voltage uniformity across particles deteriorates and selective deterioration occurs
Solution Approach 1:
The invention specifies particular particle size ranges for primary particles (0.5-5 μm) and secondary particles (5-20 μm) to optimize both production flexibility and voltage uniformity. By controlling the particle size distribution within these specific ranges and creating a hierarchical structure, the invention achieves uniform voltage characteristics across particles while maintaining adaptability in production processes.
4Power
If cathode active material with very small particle size is used, then reaction resistance is reduced, but battery capacity per volume decreases
Solution Approach 1:
The invention transitions from considering only single particle size to a two-dimensional particle size distribution (primary particles 0.5-5 μm forming secondary particles 5-20 μm). This dimensional approach allows small primary particles to provide high reaction rates while their aggregation into larger secondary particles maintains adequate packing density and battery capacity per volume, resolving the contradiction between reaction rate and capacity.
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 results in a lithium nickel composite oxide with improved battery characteristics, including high capacity, excellent cycling performance, and reduced reaction resistance, suitable for industrial-scale production and use in non-aqueous electrolyte secondary batteries.
Implementation Method 1
a method for producing nickel composite hydroxide with a controlled particle size distribution, involving a nucleation and particle growth process
Implementation Method 2
a nucleation and particle growth process
Implementation Method 3
subsequent calcination to form lithium nickel composite oxide with a hollow structure
Data Source
Figure 1(A)~1(B)
Figure 2(A)~2(B)
Figure 3(I)~3(III)
AI summary
Provided is a lithium composite oxide having a uniform and suitable particle size and high specific surface area due to a hollow structure that can be produced on an industrial scale. A nickel composite hydroxide as a raw material thereof is obtained controlling the particle size distribution of the nickel composite hydroxide, the nickel composite hydroxide having a structure comprising a center section that comprises minute primary particles, and an outer-shell section that exists on the outside of the center section and comprises plate shaped primary particles that are larger than the primary particles of the center section, by a nucleation process and a particle growth process that are separated by controlling the pH during crystallization, and by controlling the reaction atmosphere in each process and the manganese content in a metal compound that is supplied in each process.