Structured Separator Surface for Lithium Metal Anodes
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Solution Overview
Problem
Lithium-metal batteries face challenges due to the high reactivity of lithium metal, which leads to morphology changes such as dendrite formation, increasing the electrode surface area and causing internal shorts and cell failure, and the planar Li metal surface has a reduced interfacial area for reaction, resulting in high kinetic resistance.
Innovation Solution
An electrochemical cell design featuring a lithium anode with a structured separator surface that has a non-planar profile, increasing the interfacial area between the anode and separator, including angled and rounded surfaces to enhance the reaction area and reduce kinetic resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a planar separator surface is used, then the device complexity is low, but the interfacial area for reaction is reduced, resulting in high kinetic resistance
Solution Approach 1:
The separator surface is designed with a non-planar profile featuring curved and angled surfaces instead of a flat plane. This curvature increases the interfacial area between the separator and lithium metal anode, thereby reducing kinetic resistance while maintaining manufacturability through conventional forming processes.
2Use of energy by moving object
If lithium metal is used as negative electrode, then the energy density is high, but dendrite formation occurs, causing internal shorts and cell failure
Solution Approach 1:
The separator is designed with a non-planar surface profile that creates varying local geometries (angled and curved surfaces) at the interface with the lithium metal anode. This local structural variation modifies the local current distribution and lithium deposition behavior, reducing the formation of dendrites while maintaining the high energy density benefits of lithium metal.
Data Source
AI summary
An electrochemical cell in one embodiment includes an anode including a form of lithium, a cathode including an active material which intercalates lithium, and a separator positioned between the anode and the cathode, the separator including a first structured surface portion positioned in opposition to the anode, the first structured surface portion having a non-planar profile in aggregate.