Cathode Active Material Grain Control for Stable Lithium Battery Output
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Solution Overview
Problem
Lithium secondary batteries face issues with thermal and mechanical stability, leading to deteriorated life-span properties and operational reliability due to high output compositions of lithium metal oxides, and existing cathode active materials do not sufficiently address these concerns.
Innovation Solution
A cathode active material for lithium secondary batteries is developed using lithium-transition metal composite oxide particles with a crystal grain size of less than 300 nm and specific XRD peak intensity ratios, such as 7% to 12%, to enhance lithium ion diffusion and reduce cation mixing, thereby improving stability and life-span while maintaining output properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high output composition of lithium metal oxide is used, then output and capacity are improved, but thermal and mechanical stability deteriorate
Solution Approach 1:
The patent changes the crystal grain size parameter to less than 300 nm and controls the XRD peak intensity ratio I(110)/{I(110)+I(003)} to 7% or more, which modifies the material's structural parameters to achieve both high output and improved stability. This parameter optimization resolves the contradiction by finding the optimal range that balances output composition benefits with stability requirements.
Solution Approach 2:
The patent uses lithium-transition metal composite oxide as the cathode active material, combining multiple metal elements to create a composite structure. This composite material approach allows the cathode to achieve high output capacity while maintaining thermal and mechanical stability through the synergistic effects of different metal components.
2Power
If high output composition of lithium metal oxide is used, then output and capacity are improved, but life-span properties deteriorate
Solution Approach 1:
By optimizing the crystal grain size to less than 300 nm and controlling the XRD peak intensity ratio, the patent extends the operational life of the battery while maintaining high output. These parameter changes reduce structural degradation during cycling, thereby improving life-span properties without sacrificing output performance.
3Power
If high output composition of lithium metal oxide is used, then output and capacity are improved, but operational reliability deteriorates
Solution Approach 1:
The patent achieves high output with improved operational reliability by precisely controlling the crystal grain size (less than 300 nm) and XRD peak intensity ratio (7% or more). These parameter optimizations ensure stable electrochemical performance and reduce operational variability, thereby enhancing reliability while maintaining high output 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 proposed cathode active material effectively prevents output deterioration and reduces gas generation, enhancing life-span stability and capacity retention by optimizing lithium ion migration and structural integrity.
Implementation Method 1
a crystal grain size measured through X-ray diffraction (XRD) analysis of less than 300 nm and having an XRD peak intensity ratio defined by Equation 2 below of 7% or more
Implementation Method 2
enhance lithium ion diffusion and reduce cation mixing, thereby improving stability and life-span
Data Source
AI summary
The cathode active material for a lithium secondary battery includes lithium-transition metal composite oxide particles having a crystal grain size of less than 300 nm measured through XRD analysis and an XRD peak intensity ratio of 7% or more. The present invention provides a lithium secondary battery with improved life-span properties and output properties by controlling the crystal grain size and XRD peak intensity ratio of lithium-transition metal composite oxide particles.