Lithium Metal Anode Pillar Layer for Controlled Deposition
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Solution Overview
Problem
Lithium metal secondary batteries experience expansion issues due to lithium metal deposition at the negative electrode, which can lead to uneven deposition and reduced battery performance.
Innovation Solution
Incorporating a pillar layer with electrically-insulating pillars on the negative electrode current collector, where lithium ions are deposited between the pillars, reducing the likelihood of electrode thickness increase and enhancing energy density through controlled Li metal deposition and dissolution reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium metal deposition occurs at the negative electrode during charging, then the battery capacity increases, but the negative electrode thickness increases causing battery expansion
Solution Approach 1:
The negative electrode is segmented into multiple regions by introducing a pillar layer with electrically-insulating pillars. This segmentation divides the deposition space into multiple gaps between pillars, allowing lithium metal to be deposited in distributed locations rather than forming a continuous thick layer, thereby reducing overall electrode thickness increase and battery expansion.
Solution Approach 2:
The pillar layer introduces local structural variations with electrically-insulating pillars having specific dimensions and spacing. These local structural features control where lithium metal deposition occurs (in the gaps between pillars), enabling precise control over deposition distribution and preventing uniform thickness increase across the entire electrode.
2Quantity of substance
If lithium metal deposition is increased to enhance battery capacity, then energy storage increases, but deposition uniformity decreases leading to performance reduction
Solution Approach 1:
By dividing the negative electrode surface into multiple gaps separated by pillars, the segmentation creates multiple controlled deposition zones. This ensures uniform distribution of lithium metal across all gaps, preventing localized excessive deposition and maintaining consistent deposition thickness throughout the electrode.
Solution Approach 2:
The electrically-insulating pillars act as intermediary structures that mediate the lithium metal deposition process. These pillars serve as physical barriers and electrical insulators that guide and control the deposition of lithium metal into the gaps, ensuring uniform distribution and preventing direct contact between deposited lithium and the current collector.
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 solution effectively reduces battery expansion during charging and discharging, maintains uniform Li metal deposition, and enhances energy density by managing Li metal distribution within the pillar layer framework.
Implementation Method 1
A charging reaction of the negative electrode is a deposition reaction of a lithium metal occurring in a gap between the electrically-insulating pillars
Implementation Method 2
A discharging reaction of the negative electrode is a dissolution reaction of the lithium metal occurring in the gap
Data Source
AI summary
A lithium metal secondary battery comprises a positive electrode, a negative electrode, and an electrolyte. The negative electrode includes a negative electrode current collector and a pillar layer. The pillar layer is placed on a surface of the negative electrode current collector. The pillar layer includes a plurality of electrically-insulating pillars. Each of the plurality of electrically-insulating pillars extends in a direction heading from the surface of the negative electrode current collector toward the positive electrode. Lithium ions are dissolved in the electrolyte. A charging reaction of the negative electrode is a deposition reaction of a lithium metal occurring in a gap between the electrically-insulating pillars. A discharging reaction of the negative electrode is a dissolution reaction of the lithium metal occurring in the gap.