Lithium Electrode Silicon Coating Moisture Resistance
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Solution Overview
Problem
Lithium secondary batteries face safety concerns due to high energy density, which can lead to explosion or fire, and there is a need for high-capacity anode materials that are lightweight and efficient in portable electronic devices and hybrid vehicles.
Innovation Solution
A lithium electrode with a lithium metal layer having a hydroxyl group on its surface and a silicon layer formed from a silicon-based compound that forms covalent bonds with a hydroxyl group of a lower membrane, reducing interfacial resistance and enhancing lithium ion transfer while blocking moisture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a lithium secondary battery uses high energy density to achieve high capacity and operating voltage, then battery capacity and power are improved, but safety deteriorates due to risk of explosion or fire
Solution Approach 1:
A silicon-based compound layer is introduced as an intermediary between the lithium metal layer and the electrolyte. This intermediate layer forms covalent bonds with hydroxyl groups on the lithium metal surface, creating a protective interface that prevents direct contact between lithium metal and moisture in the electrolyte, thereby improving safety while maintaining high capacity
Solution Approach 2:
The battery electrode uses a composite structure combining lithium metal with a silicon-based compound coating. This composite material approach allows the lithium metal to provide high capacity while the silicon-based compound provides stability and safety, resolving the contradiction between high energy density and safety
2Reliability
If a silicon layer is formed on lithium metal layer to block moisture and improve safety, then battery safety and life are improved, but interfacial resistance increases which reduces charge and discharge efficiency
Solution Approach 1:
The silicon-based compound layer is designed with specific chemical properties - it forms covalent bonds with hydroxyl groups on the lithium metal surface, creating a chemically stable interface. This parameter change in the interface chemistry reduces interfacial resistance while maintaining the protective moisture-blocking function, thus improving both safety and efficiency
3Quantity of substance
If high capacity lithium anode materials are used to increase energy density, then battery capacity is improved, but moisture sensitivity increases leading to reduced stability
Solution Approach 1:
The silicon-based compound acts as a mediator that forms a stable protective layer on the lithium metal surface through covalent bonding with hydroxyl groups. This intermediate layer is highly resistant to moisture penetration, protecting the high-capacity lithium anode material from degradation while maintaining its high capacity characteristics
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
The lithium electrode achieves long life, efficient charge and discharge, low interfacial resistance, and improved lithium ion transfer by preventing moisture penetration and forming a stable protective layer, thus enhancing battery safety and performance.
Implementation Method 1
the silicon-based compound of the silicon layer forms covalent bonds with a hydroxyl group of a lower membrane that is in contact with the silicon layer
Implementation Method 2
A lithium electrode according to one embodiment of the present specification can be efficiently blocked from moisture
Data Source
AI summary
The present specification relates to a lithium electrode, a lithium secondary battery including the same, a battery module including the lithium secondary battery, and a method for preparing a lithium electrode.