Fm-3m Space Group Positive Electrode Material for High Capacity Batteries
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Solution Overview
Problem
Existing battery technologies face challenges in achieving high capacity and stability due to limitations in the oxidation-reduction reactions and crystal structure maintenance, particularly with lithium ion batteries, where the R-3m space group layered structure is unstable when a large amount of Li is pulled out.
Innovation Solution
A positive electrode active material with a crystal structure belonging to the Fm-3m space group, represented by the composition formula LixMeyOαXβ, where Me includes elements like Mn, Ni, and X is a halogen such as Cl, Br, I, N, or S, optimizing the ratios of x, y, α, and β to enhance capacity and stability by promoting oxidation-reduction reactions and maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large amount of Li is pulled out to increase capacity, then the battery capacity increases, but the R-3m space group layered structure becomes unstable
Solution Approach 1:
The patent changes the crystal structure parameter from R-3m space group to Fm-3m space group, which fundamentally alters the structural stability characteristics. This parameter change allows the material to maintain structural integrity even when significant amounts of lithium are extracted, thereby enabling high capacity while preserving stability.
Solution Approach 2:
The patent employs composite material design by incorporating multiple elements (Li, Me, O, and X where X is Cl, Br, I, N, or S) in specific ratios defined by the formula LixMeyOαXβ. This composite approach creates a more robust crystal structure that resists degradation during lithium extraction cycles.
2Power
If elements with high electronegativity are introduced to improve discharge capacity and operating voltage, then energy density increases, but the complexity of material composition increases
Solution Approach 1:
The patent applies local quality by strategically introducing elements with high electronegativity (Cl, Br, I, N, or S) at specific positions in the crystal structure (represented by the X parameter in LixMeyOαXβ). This localized introduction of electronegative elements enhances discharge capacity and operating voltage without requiring the entire material composition to be complex.
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 configuration results in a battery with a high capacity and energy density, maintaining structural stability even when a large amount of Li is pulled out, and improves discharge capacity and operating voltage by utilizing elements with high electronegativity, thereby achieving a higher energy density of approximately 3,200 Wh/L or more.
Implementation Method 1
a battery having a high capacity can be realized... promoting oxidation-reduction reactions
Data Source
AI summary
A positive electrode active material comprising: a compound which has a crystal structure belonging to space group Fm-3m and which is represented by the following composition formula: LixMeyOαXβ. In the formula, the Me represents one or more elements selected from the group consisting of Mn, Ni, Co, Fe, Al, Sn, Cu, Nb, Mo, Bi, Ti, V, Cr, Y, Zr, Zn, Na, K, Ca, Mg, Pt, Au, Ag, Ru, Ta, W, La, Ce, Pr, Sm, Eu, Dy, and Er. The X represents one element selected from the group consisting of Cl, Br, I, N, and S. The following conditions are satisfied: 0.5≤x≤1.5; 0.5≤y≤1.0; 1≤α<2; and 0<β≤1.