Positive Electrode Active Material Structure for Faster Lithium Diffusion
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Solution Overview
Problem
Lithium-ion secondary batteries face challenges in achieving high output due to low lithium diffusion rates in existing composite oxides like LiFePO4, limiting their performance in applications such as HEVs, EVs, and stationary batteries.
Innovation Solution
A lithium-ion secondary battery design incorporating a positive electrode active material with a plate-like component structure, featuring a prismatic component between plate-like components and a space between them, optimized for high lithium diffusion rates, enhancing the reaction speed and output of the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional composite oxide structures are used, then thermal stability is maintained, but lithium diffusion rate is low
Solution Approach 1:
The positive electrode active material is divided into plate-like components with specific geometric features (first surface, second surface, third surface with different areas). This segmentation creates multiple exposed surfaces that increase the overall surface area for lithium ion diffusion, directly addressing the low diffusion rate issue while maintaining the thermal stability of the composite oxide structure
Solution Approach 2:
The invention transitions from conventional particle structures to a plate-like component structure with distinct surfaces and orientations. By creating a three-dimensional plate structure with a first surface, second surface, and third surface having different areas, the patent enables lithium diffusion from multiple directions and surfaces, significantly increasing the effective diffusion area and rate
2Productivity
If high output is achieved through increased lithium diffusion, then battery performance improves, but manufacturing complexity increases
Solution Approach 1:
The patent specifies precise geometric parameters for the plate-like components, including the relationship between the first surface area, second surface area, and third surface area. By controlling these dimensional parameters during synthesis, the invention optimizes lithium diffusion pathways and surface area exposure, achieving high output while providing clear manufacturing specifications that facilitate reproduction
3Speed
If plate-like component structure with multiple surfaces is used, then lithium diffusion rate increases, but structural complexity increases
Solution Approach 1:
The positive electrode active material is divided into plate-like components with specific geometric features (first surface, second surface, third surface with different areas). This segmentation creates multiple exposed surfaces that increase the overall surface area for lithium ion diffusion, directly addressing the low diffusion rate issue while maintaining the thermal stability of the composite oxide structure
Solution Approach 2:
The plate-like components feature asymmetric surface area distribution, where the first surface has a larger area than the third surface, and the second surface has a larger area than the third surface. This asymmetric geometry optimizes lithium diffusion by providing larger active surfaces while maintaining structural integrity, balancing complexity with performance
Data Source
AI summary
A lithium-ion secondary battery including a lithium-containing complex phosphate as a positive electrode active material is provided. Furthermore, a positive electrode active material with high diffusion rate of lithium ions is provided to provide a lithium-ion secondary battery with high output. A positive electrode active material of a lithium-ion secondary battery includes a first plate-like component and a second plate-like component, a third prismatic component between the first component and the second component, and a space between the first component and the second component.