Multilayer Electrode Structure for Overload Tolerance
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Solution Overview
Problem
Existing electrode materials, such as those based on LiFePO4/LiCoO2, exhibit limited interest due to insufficient resistance to overcharges, leading to safety concerns and performance issues in portable electronic systems and hybrid vehicles.
Innovation Solution
Development of multi-layer materials with specific properties, including two superposed solid layers with minimal interpenetration, where the first layer adheres to a solid support and the second layer adheres to the first, using electrochemically active materials like complex oxides, with distinct binders and thicknesses, and optionally a protective layer, to enhance mechanical and electrochemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If double-layer electrodes based on LiFePO4/LiCoO2 are used, then some progress in overload tolerance is achieved, but the resistance to overcharges remains insufficient leading to safety concerns
Solution Approach 1:
The electrode is divided into multiple layers with distinct functions: a first layer containing LiFePO4 particles provides structural stability and safety, while a second layer containing LiCoO2 particles delivers high capacity. This segmentation allows each layer to optimize its specific role, resolving the contradiction between safety and performance.
Solution Approach 2:
The invention uses a composite structure combining LiFePO4 and LiCoO2 materials in a multi-layer configuration. The LiFePO4 layer provides thermal stability and safety against overcharges, while the LiCoO2 layer contributes high electrochemical capacity, achieving both reliability and performance simultaneously.
2Reliability
If multi-layer materials with minimal interpenetration are used, then exceptional safety and resistance to overloads are achieved, but the device complexity increases
Solution Approach 1:
The electrode is segmented into distinct layers with clear boundaries and minimal interpenetration. This segmentation simplifies the control of each layer's thickness and composition, making the manufacturing process more manageable despite the multi-layer structure.
Solution Approach 2:
Each layer is designed with specific local properties: the LiFePO4 layer has optimized thickness and composition for safety, while the LiCoO2 layer is tailored for high capacity. This local optimization allows complex functionality to be achieved through simple, well-defined layer characteristics.
Data Source
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AI summary
The invention concerns a multilayer material comprising a solid substrate and at least two superimposed solid layers containing particles of an electrochemically active material, the first solid layer adhering to the solid substrate and the second layer adhering to the first solid layer. Said multilayer material has a constant thickness of upper layer not less than 95% and a depth of penetration of the second layer into the first layer which is less than 10% of the thickness of the first layer, and enables as electrode constituent, generators having a low risk of overload degradation to be prepared.