Lithium Metal Composite Oxide for Suppressing Gas Generation
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Solution Overview
Problem
Lithium secondary batteries face challenges in reducing gas generation at the positive electrode, which affects their performance and reliability, particularly as they are used in larger applications.
Innovation Solution
A lithium metal composite oxide with specific composition and structural characteristics is developed, including a particular ratio of integral intensities in X-ray diffraction measurements, a low BET specific surface area, and defined particle sizes, to minimize gas generation by reducing the contact area with the electrolytic solution and preventing decomposition reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the positive electrode active material is used to improve battery capacity, then the battery performance is enhanced, but gas generation increases due to decomposition reactions with the electrolytic solution
Solution Approach 1:
The invention changes the physical parameters of the positive electrode active material, specifically controlling the particle size distribution (D10 ≥ 5 μm) and BET specific surface area (0.7 m²/g or less). These parameter changes reduce the contact area between the material and electrolytic solution, thereby suppressing decomposition reactions and gas generation while maintaining battery capacity
Solution Approach 2:
The invention uses a composite oxide material with specific composition (Li1+xM1-yMwO3 where M includes elements like Ni, Co, Mn, Al, Ti, etc.) that combines multiple metal elements to achieve both high capacity and low gas generation. The composite structure provides improved stability and reduced reactivity with the electrolytic solution
2Productivity
If the contact area with electrolytic solution is increased to improve reaction efficiency, then charge/discharge characteristics are enhanced, but gas generation amount increases
Solution Approach 1:
The invention optimizes the particle size distribution parameters (D10 ≥ 5 μm, D50/average primary particle diameter ≤ 2.0) to achieve a balance between contact area and gas generation. This parameter control ensures sufficient reaction efficiency while minimizing harmful gas production
Solution Approach 2:
The invention creates local quality differences by controlling the particle size distribution, where larger particles (D10 ≥ 5 μm) provide reduced surface area for gas generation while maintaining adequate contact areas for efficient charge/discharge reactions
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 lithium metal composite oxide effectively suppresses gas generation, enhancing the cycle performance and thermal stability of lithium secondary batteries, leading to improved reliability and efficiency.
Implementation Method 1
a BET specific surface area is 0.7 m2/g or less
Data Source
AI summary
The present invention relates to a lithium metal composite oxide represented by the composition formula (I), the lithium metal composite oxide satisfies requirements (1) to (3):(1) a ratio (I1/I2) of an integral intensity I1 of a diffraction peak in a range of 2θ= 36.7 ± 1° with respect to an integral intensity I2 of a diffraction peak in a range of 2θ= 64.9 ± 1° in a powder X-ray diffraction measurement for the lithium metal composite oxide using Cu—Kα ray is 2.0 or more;(2) a BET specific surface area is 0.7 m2/g or less; and(3) a 10% cumulative volume particle size D10 is 5 µm or more.