Lithium Metal Anode Recess Structure for Dendrite Suppression
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Solution Overview
Problem
Lithium metal secondary batteries face issues with dendrite deposition leading to short circuits, especially under uneven load conditions in solid-state batteries, which affects cycle characteristics during charge and discharge.
Innovation Solution
A battery cell design featuring a negative electrode active material layer with cone or pyramid-shaped recess portions and planar portions on its surface adjacent to the electrolyte layer, which preferentially directs dendrite growth into recess areas, reducing the risk of short circuits and improving cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is used as negative electrode active material to achieve high energy density, then energy efficiency is improved, but dendrite deposition occurs leading to short circuits
Solution Approach 1:
The invention applies local quality by creating recess portions at specific locations on the negative electrode surface where dendrites are most likely to form. These recess portions have different geometric properties (depression, curved surface) compared to the surrounding planar regions, providing localized control over dendrite growth behavior without changing the overall electrode structure or material composition.
Solution Approach 2:
The recess portions are formed in advance on the negative electrode surface before battery operation begins. This preliminary structural modification creates predetermined sites that guide dendrite growth away from critical areas, preventing short circuits before they can occur during charge-discharge cycles.
2Stability of the object's composition
If a solid electrolyte is used to improve battery stability, then reliability is improved, but uneven distribution of restraining load causes dendrite-induced short circuits
Solution Approach 1:
The invention introduces local quality variations on the negative electrode surface through recess portions, creating specific zones with different mechanical and geometric properties. These localized features modify how restraining load is distributed and how dendrites interact with the solid electrolyte interface, addressing the uneven load distribution problem without compromising overall battery stability.
3Reliability
If fine irregularities are formed on substrate surface to suppress dendrite growth, then dendrite suppression is improved, but strong restraining load affects electrode performance
Solution Approach 1:
The invention segments the negative electrode surface into distinct regions: recess portions where dendrites are suppressed, and planar portions that maintain good electrical contact and ion transport. This segmentation allows dendrite suppression functionality to be localized to specific areas while preserving overall electrode productivity through the planar regions.
Solution Approach 2:
By creating localized recess portions rather than uniform surface irregularities, the invention concentrates the dendrite-suppressing effect in specific areas while maintaining large planar regions for efficient charge-discharge operations. This local quality approach prevents the strong restraining load from being distributed across the entire electrode surface.
4Reliability
If recess portions are formed on negative electrode surface to direct dendrite growth, then short circuit risk is reduced, but manufacturing complexity increases
Solution Approach 1:
The recess portions create a controlled porous-like structure on the negative electrode surface, forming three-dimensional features that guide dendrite growth. This approach uses simple geometric modifications (depressions, curved surfaces) rather than complex multi-layer structures, achieving short circuit prevention with relatively simple structural additions.
Data Source
AI summary
To provide a battery cell capable of suppressing deposition of dendrites and improving cycle characteristics. A battery cell having a negative electrode layer, an electrolyte layer, and a positive electrode layer, the negative electrode layer comprising a negative electrode active material layer that has at least one recess portion and at least one planar portion on a surface of the negative electrode active material layer, the surface being adjacent to the electrolyte layer, the recess portion being a cone or pyramid-shaped recess portion having a slant portion. The negative electrode active material layer comprises lithium metal, and the electrolyte layer is preferably a solid electrolyte layer comprising a solid electrolyte. When the at least one recess portion and the at least one planar portion comprise a plurality of recess portions and a plurality of planar portions, respectively, each of the planar portions is formed between the plurality of recess portions.