Lithium Metal Battery Anode Structure for Uniform Li Deposition
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Solution Overview
Problem
Lithium metal secondary batteries face challenges in maintaining the reversibility of negative electrode reactions due to Li dendrite growth, which can impair performance and longevity.
Innovation Solution
The battery design incorporates a negative electrode with electrically conductive base material featuring raised, electrically insulating portions and depressed portions, where the seed materials like Li, Mg, Al, Zn, Ag, Pt, or Au are placed inside the depressed areas to facilitate uniform Li deposition and dissolution, enhancing reaction reversibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a raised portion is provided to the negative electrode current collector to form accommodation space, then Li deposition reversibility is improved, but dendrite formation at the tip of the raised portion may occur
Solution Approach 1:
The current collector surface is designed with locally differentiated properties: electrically conductive depressed portions that promote uniform Li deposition and electrically insulating raised portions that prevent dendrite formation. This local quality differentiation allows the same structure to simultaneously improve reversibility and prevent harmful dendrite growth at critical locations.
Solution Approach 2:
The raised portions, which could potentially become sites for dendrite formation due to electron supply, are converted into beneficial anti-dendrite structures by making them electrically insulating. This transforms what could be a harmful feature into a protective element that actively prevents dendrite growth while maintaining the accommodation space function.
2Reliability
If the base material has a large surface area to facilitate Li deposition, then reaction uniformity is improved, but the structure becomes more complex
Solution Approach 1:
The current collector surface is segmented into distinct functional regions: depressed portions for Li deposition and raised portions for dendrite prevention. This segmentation achieves reaction uniformity through controlled surface area distribution while maintaining relatively simple manufacturing processes, as the segmented structure can be created through conventional techniques.
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
This configuration improves the uniformity and reversibility of negative electrode reactions, reducing the likelihood of Li dendrite formation and enhancing the battery's performance and lifespan.
Implementation Method 1
The raised portions are electrically insulating. It is conceivable that electrons are not supplied to the raised portions.
Implementation Method 2
During charging, Li ions receive electrons at the surface of the negative electrode current collector and thereby Li is deposited.
Implementation Method 3
Li deposition on the surface of the base material is expected to be facilitated. When the depth of the depressed portions and the height of the raised portions satisfy a certain relationship, Li deposition reaction and Li dissolution reaction inside the accommodation space are expected to be facilitated.
Data Source
AI summary
A lithium metal secondary battery comprises a power generation element and an electrolyte. The power generation element includes a positive electrode and a negative electrode. The negative electrode includes a base material and raised portions. The base material is electrically conductive. The raised portions are electrically insulating. Depressed portions are formed on a surface of the base material. The raised portions are provided on a surface of the base material. The raised portions protrude outwardly from the surface of the base material. A relationship of the expression “0.001≤d/h≤10” is satisfied. d represents a depth of the depressed portions. h represents a height of the raised portions.