Layered Oxide Cathode Material for Lower Li+ Transport Resistance
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Solution Overview
Problem
Lithium ion batteries face challenges in reducing initial resistance in positive electrode active materials, particularly in secondary particles with core-shell structures, where the resistance remains high despite the presence of conductive components like cobalt.
Innovation Solution
The introduction of lithium-containing layered transition metal oxides with a randomized crystal structure, as evidenced by a half-value width of luminance greater than 39 in transmission electron microscopy images, enhances the entry and exit of Li+ ions, thereby reducing resistance and improving cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the crystal structure has high directionality, then the structure is stable, but the entry and exit of Li+ ions is limited
Solution Approach 1:
The patent changes the orientation parameter of the crystal structure by controlling the half-value width of luminance in the histogram to be 39 or more. This reduces the directional alignment while maintaining structural stability, thereby improving Li+ ion transport capability without sacrificing crystal structure integrity.
Solution Approach 2:
The patent creates a composite structure within the primary particle where crystal structures with varying orientations coexist. This composite arrangement of crystal orientations allows the material to maintain stability while providing multiple pathways for Li+ ion entry and exit.
Data Source
AI summary
A positive electrode active material includes a secondary particle. The secondary particle includes a primary particle. The primary particle includes lithium-containing layered transition metal oxide. In a bright field image by transmission electron microscopy, a histogram of luminance of the primary particle has a peak. The peak has a half-value width of 39 or more.