Lithium Composite Oxide with Dissolved W Mo Ta for Battery Output
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Solution Overview
Problem
Existing non-aqueous electrolyte secondary batteries with positive electrode active materials containing composite oxides of lithium and elements like W, Mo, and Ta do not exhibit sufficient output characteristics, particularly at low temperatures due to surface localization of these elements and small particle sizes.
Innovation Solution
A positive electrode active material with a lithium composite oxide having a Ni content exceeding 30 mol % and incorporating elements like W, Mo, or Ta, where these elements are dissolved and dispersed within the particles, forming larger primary particles with improved aggregation and ion conductivity, enhancing energy density and bulk density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If elements like W, Mo, Nb, and Ta are added to lithium composite oxide, then output characteristics are improved, but the elements localize at the particle surfaces rather than being uniformly distributed
Solution Approach 1:
The patent changes the chemical composition parameters by specifying precise ratios of Li, Ni, Co, Mn, and other elements (W, Mo, Nb, Ta) in the lithium composite oxide. By controlling the composition within specific ranges (e.g., Ni: 0.2-0.4 mol ratio, W: 0.01-0.1 mol ratio), the patent achieves uniform element distribution while maintaining improved output characteristics.
Solution Approach 2:
The patent creates a composite lithium composite oxide material containing multiple elements (Li, Ni, Co, Mn, W/Mo/Nb/Ta) in specific combinations. This composite structure allows the beneficial effects of different elements to be combined while maintaining uniform distribution, resolving the localization problem through proper material design.
2Productivity
If the particle size of lithium composite oxide is reduced to improve surface area, then reaction activity increases, but bulk density and energy density decrease
Solution Approach 1:
The patent optimizes the particle size parameter to a specific range (0.5-5 μm) that balances surface area for reaction activity with sufficient volume for bulk density. This parameter optimization resolves the contradiction by finding the optimal size where both reaction activity and energy density are maximized.
Solution Approach 2:
The patent creates particles with non-uniform element distribution at different scales: uniform distribution of W/Mo/Nb/Ta at the atomic level within the crystal structure, while maintaining overall particle size uniformity. This local quality control ensures both high reaction activity and good bulk density.
3Quantity of substance
If Ni content in lithium composite oxide is increased to improve capacity, then energy density increases, but low-temperature performance deteriorates
Solution Approach 1:
The patent creates a composite lithium composite oxide with Ni combined with Co, Mn, and other elements (W, Mo, Nb, Ta) in specific ratios. This composite structure maintains high Ni content (0.2-0.4 mol ratio) for capacity while the other elements mitigate the low-temperature performance degradation, resolving the contradiction through synergistic material design.
Solution Approach 2:
The patent optimizes the Ni content parameter within a specific range (0.2-0.4 mol ratio) rather than using maximum Ni content. This parameter optimization balances capacity with low-temperature performance, and further refines the composition by adding controlled amounts of other elements to maintain reliability across temperature ranges.
Data Source
AI summary
A positive electrode active material for a non-aqueous electrolyte secondary battery according to an example of an embodiment of the present disclosure includes a lithium composite oxide as a main component. The ratio of a number of moles of Ni in the lithium composite oxide to a total number of moles of metal elements in the lithium composite oxide other than Li is larger than 30 mol %. The lithium composite oxide includes particles each including aggregated primary particles having a volumetric average particle size of 0.5 μm or more and at least one element selected from W, Mo, Nb, and Ta is dissolved in the lithium composite oxide.