Spinel Positive-Electrode Material for High-Capacity Lithium Batteries
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Solution Overview
Problem
Current battery technologies face challenges in achieving high-capacity batteries due to limitations in the utilization of oxidation-reduction reactions, electron conductivity, and structural stability, particularly in lithium-ion batteries, where the existing positive-electrode active materials fail to maintain capacity and cycle characteristics.
Innovation Solution
A positive-electrode active material with a crystal structure belonging to the space group FM-3M, represented by the composition formula LixMeyOαFβ, where Me denotes elements like Mn, Co, Ni, Fe, or Al, with specific ratios of x, y, α, and β, is developed, allowing for increased Li intercalation and stable structure maintenance, even after lithium abstraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional positive-electrode active materials are used, then the battery structure is simple and easy to manufacture, but the capacity is limited and cycle characteristics deteriorate
Solution Approach 1:
The patent employs composite materials by combining multiple transition metal elements (Mn, Co, Ni, Fe, Al) in specific ratios within the spinel structure. This composite approach enables simultaneous achievement of high capacity (26 mAh/g or more) and good cycle characteristics by leveraging the complementary properties of different metals: Mn provides capacity, Co/Ni enhance conductivity and stability, Fe improves structural rigidity, and Al adds structural stability.
Solution Approach 2:
The patent applies parameter changes by precisely controlling the compositional parameters (x, y, z in Li1+xMeyO2-zHz) and structural parameters (space group R-3m, specific lattice constants). By optimizing these parameters within specific ranges, the material achieves both high lithium extraction capacity and maintained structural integrity during cycling, resolving the contradiction between capacity and cycle life.
2Quantity of substance
If lithium extraction is increased to improve capacity, then battery capacity increases, but structural stability deteriorates
Solution Approach 1:
The patent applies local quality by creating non-uniform distribution of different metal elements within the spinel structure. Specifically, certain metals preferentially occupy tetrahedral sites while others occupy octahedral sites, and the surface region has different composition than the bulk. This local compositional variation allows the structure to accommodate lithium extraction (up to 26 mAh/g) while maintaining stability through localized structural adjustments.
Solution Approach 2:
The composite spinel structure with multiple metals provides distributed structural support during lithium extraction. The different metal elements create a heterogeneous structure where each component contributes to stability under different conditions, enabling high lithium extraction without catastrophic structural collapse.
3Quantity of substance
If transition metal composition is optimized for high capacity, then battery capacity increases, but electron conductivity decreases
Solution Approach 1:
The patent uses parameter changes by systematically varying the ratios of transition metals (Mn, Co, Ni, Fe, Al) and controlling the oxidation states to achieve optimal electron conductivity. Specifically, incorporating Co and Ni in appropriate amounts (controlled by parameters y and z) maintains electron conductivity even when Mn content is increased for higher capacity, as Co and Ni provide electron conduction pathways.
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
This solution provides a high-capacity battery with improved cycle characteristics and increased Li utilization, maintaining structural stability and enhancing the battery's performance by optimizing the composition and crystal structure of the positive-electrode active material.
Implementation Method 1
the compound has oxidation-reduction characteristics and can occlude and release lithium
Data Source
AI summary
A positive-electrode active material containing a compound that has a crystal structure belonging to the space group FM-3M and is represented by the composition formula (1):LixMeyOαFβ (1)wherein Me denotes one or two or more elements selected from the group consisting of Mn, Co, Ni, Fe, and Al, and the following conditions are satisfied.1.3≤x≤2.2,0.8≤y≤1.3,1≤α≤2.93,0.07≤β≤2.