Cathode Active Material Void Structure for High-Rate Li-Ion Batteries
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Solution Overview
Problem
Current lithium secondary battery positive-electrode active materials do not adequately enhance rate characteristics, limiting the performance of lithium secondary batteries in high-rate discharge applications.
Innovation Solution
A positive-electrode active material comprising secondary particles of lithium composite metal oxide with a void structure and through-holes connecting the void to the surface, optimized by specific geometric and void fraction parameters to improve sphericity, fillability, and electrolyte retention, enhancing the battery's rate characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a hollow structure with through-holes is formed in secondary particles, then rate characteristics are improved, but manufacturing precision and structural control become more difficult
Solution Approach 1:
The patent applies porous materials by forming voids and through-holes in the secondary particle structure. The secondary particle contains a void inside and through-holes connecting the void to the surface, creating a porous architecture that enhances electrolyte infiltration and lithium ion diffusion, thereby improving rate characteristics while maintaining structural integrity
Solution Approach 2:
The patent applies segmentation by dividing the secondary particle into distinct structural zones: primary particles aggregated to form the secondary particle, internal voids, and through-holes. This segmentation creates a hierarchical structure where each level serves specific functions - primary particles provide active material, voids provide expansion space, and through-holes provide transport channels
2Ease of operation
If secondary particles have void structure, then electrolyte infiltration is improved, but particle strength and structural stability may deteriorate
Solution Approach 1:
The patent applies local quality by creating different structural characteristics in different regions of the secondary particle. The surface region maintains sufficient density for strength, while the internal region contains voids for electrolyte infiltration. The through-holes are strategically positioned to connect the void to the surface, providing localized pathways for electrolyte access without compromising overall particle integrity
Solution Approach 2:
The patent applies composite materials by combining solid primary particles with void spaces to create a composite secondary particle structure. This composite architecture integrates the strengths of dense material (structural support) with the benefits of porous structure (electrolyte access), achieving both mechanical stability and enhanced infiltration
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 optimized active material significantly improves the rate characteristics of lithium secondary batteries by allowing better electrolyte infiltration and stress relief, leading to enhanced discharge efficiency and reduced electron conduction losses.
Implementation Method 1
a through-hole that connects the void to a surface of the secondary particle
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
A positive-electrode active material for a lithium secondary battery includes: a secondary particle in which a plurality of primary particles of a lithium composite metal oxide are aggregated, in which the secondary particle has a void formed therein, and a through-hole that connects the void to a surface of the secondary particle, and satisfies predetermined requirements (i) to (iii).