Lithium Electrode Protective Layer for Moisture Barrier and Dendrite Control
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Solution Overview
Problem
Lithium metal electrodes in batteries are prone to moisture damage and dendrite formation, which reduces battery lifetime and energy density, as existing protective layers like PVdF-HFP lack sufficient moisture barrier properties.
Innovation Solution
A lithium electrode with a protective layer formed from an olefin-based ion conducting polymer, such as cyclic olefin copolymer (COC), which provides enhanced moisture barrier and lithium ion conductivity, minimizing dendrite growth and oxide layer formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PVdF-HFP is used as a protective layer material, then the protective layer can be formed on lithium metal, but moisture barrier properties are insufficient causing lithium metal damage
Solution Approach 1:
The patent changes the material parameter of the protective layer from PVdF-HFP to COC (cyclic olefin copolymer), which has inherently superior moisture barrier properties. This material substitution resolves the contradiction by providing both adequate protection against moisture and maintaining lithium ion conductivity.
Solution Approach 2:
The patent employs a composite structure consisting of a COC protective layer combined with a releasing agent layer (such as silicon oxide or fluorinated compounds). This composite material approach enhances the moisture barrier properties while maintaining compatibility with lithium metal and ensuring lithium ion conductivity.
2Ease of manufacture
If lithium metal is exposed during deposition, then the lithium electrode can be formed, but oxide layer thickness increases adversely affecting lifetime properties
Solution Approach 1:
The patent applies a protective layer (COC) and releasing agent layer to the substrate before depositing lithium metal. This preliminary action creates a controlled environment that prevents oxide layer formation during lithium deposition, resolving the contradiction between ease of manufacture and lifetime properties.
Solution Approach 2:
The patent creates an inert environment by using COC as a protective layer material, which has low reactivity and prevents oxidation of lithium metal during the deposition process. This inert environment approach allows lithium electrode formation while minimizing oxide layer formation that would harm lifetime properties.
3Use of energy by moving object
If lithium metal is used to increase energy density, then battery weight decreases and capacity increases, but handling difficulty increases due to high reactivity
Solution Approach 1:
The patent uses a thin film protective layer made of COC that flexibly covers the lithium metal surface. This thin film approach provides adequate protection against moisture and oxidation while maintaining the low weight and high energy density benefits of lithium metal, resolving the handling difficulty without sacrificing energy density.
4Reliability
If a protective layer is added to protect lithium metal, then moisture barrier properties improve, but device complexity increases
Solution Approach 1:
The patent simplifies the protective layer structure by using a single-layer COC coating instead of multi-layer complex structures. This parameter change in material selection provides adequate moisture barrier properties while minimizing device complexity.
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 use of an olefin-based ion conducting polymer as a protective layer significantly enhances battery performance by preventing moisture exposure and lithium dendrite formation, leading to improved energy density and extended battery life.
Implementation Method 1
introducing an olefin-based ion conducting polymer such as a cyclic olefin copolymer (COC) having ion conductivity and hydrophobicity properties
Implementation Method 2
exhibiting excellent moisture barrier properties for lithium metal
Implementation Method 3
having ion conductivity and hydrophobicity properties
Implementation Method 4
moisture barrier properties for lithium metal and lithium ion conductivity
Implementation Method 5
minimizing oxide layer formation
Data Source
AI summary
A lithium electrode and a lithium secondary battery including the same. By using an olefin-based ion conducting polymer as a protective layer-forming material of a lithium electrode having a protective layer formed on a lithium metal layer, the lithium electrode may be protected from moisture or open air during a lithium electrode preparation process, lithium dendrite formation and growth from the lithium electrode may be prevented, and performance of a battery using the lithium electrode may be enhanced.