Stabilized Electrodes for Lithium Batteries via Composite Materials
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Solution Overview
Problem
State-of-the-art lithium batteries fail to provide sufficient energy for electric vehicles due to voltage fade in 'layered-layered' electrode materials, which limits their driving range and efficiency.
Innovation Solution
Development of multi-component, composite lithium metal oxide materials with inhomogeneous layered and spinel-type structures, where the composition and structure vary across individual particles, incorporating a gradient of lithium and metal ions to stabilize the electrode performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If layered-layered electrode materials (xLi2MnO3•(1-x)LiMO2) are used to achieve high capacity, then the energy capacity is improved, but voltage fade occurs on repeated cycling which reduces energy output and efficiency
Solution Approach 1:
The patent applies composite materials by combining layered Li2MnO3 and LiMO2 components with spinel LiM''2O4 to form a multi-component composite electrode material. This composite structure integrates the high capacity advantage of layered materials with the structural stability of spinel materials, thereby maintaining high energy capacity while suppressing voltage fade through the synergistic effect of different material phases.
Solution Approach 2:
The patent implements local quality by creating compositionally inhomogeneous electrode particles with a core-shell structure. The core region contains a different composition (higher Li2MnO3 content) compared to the surface region (higher spinel content), allowing different parts of the same particle to fulfill different functions: the core provides high capacity while the surface provides structural stability and suppresses voltage fade.
2Ease of manufacture
If homogeneous electrode materials are used, then the manufacturing process is simple, but the electrode performance cannot suppress voltage fade effectively
Solution Approach 1:
The patent creates local quality variations within electrode particles by forming a core-shell structure where the core and surface have different compositions. This is achieved through controlled synthesis processes that allow different regions of the particle to develop distinct chemical compositions, enabling voltage fade suppression at the particle surface while maintaining high capacity in the core.
Solution Approach 2:
The patent uses composite materials with multiple phases (layered and spinel) that are distributed non-uniformly within the electrode particles. This composite approach allows the material to exhibit both high capacity and voltage stability, resolving the contradiction between manufacturing simplicity and performance effectiveness.
3Power
If high capacity cathode materials are used to meet energy demands, then the energy output is improved, but voltage fade reduces the efficiency of cell operation
Solution Approach 1:
The patent employs composite materials combining layered Li2MnO3-LiMO2 with spinel LiM''2O4 to create an electrode that delivers high energy output while maintaining operational efficiency. The spinel component specifically addresses voltage fade, ensuring that the high capacity is maintained throughout cycling, thereby preserving both power and productivity.
Solution Approach 2:
By creating compositionally graded particles with different regions having different properties, the patent enables the electrode to simultaneously achieve high energy output and high operational efficiency. The surface region with higher spinel content maintains voltage stability during cycling, while the core region provides high capacity, thus resolving the contradiction between power and productivity.
Data Source
AI summary
A structurally inhomogeneous lithium metal oxide material having the Formula (I): y[xLi2MO3•(1-x)LiM′O2]•(1-y)Li1+dM″2−dO4; wherein 0≤x≤1; 0<y<1; 0≤d≤0.33; and wherein the Li1+dM″2−dO4 component comprises a spinel structure, and each of the Li2MO3 and the LiM′2 components thereof comprise layered structures. Each of M, M′, and M″ independently comprises one or more metal ions. The composition of the material of Formula (I) varies across the electrode particles by changing at least one of x, y, d, M, M′ and M″. Electrodes, cells and batteries comprising the lithium metal oxide material are also described.