Lithium Battery Negative Electrode Coating for Dendrite Suppression
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Solution Overview
Problem
Conventional lithium secondary batteries face challenges in achieving high energy density and cycle characteristics due to the limitations of negative electrode active materials, leading to issues such as dendritic lithium metal formation and reduced capacity.
Innovation Solution
A lithium secondary battery design without a negative electrode active material, where the surface of the negative electrode is coated with a compound containing an aromatic ring with bonded N, S, or O elements, facilitating lithium metal deposition and dissolution, and using a separator or solid electrolyte to prevent short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a negative electrode active material is used, then the battery structure is complete and can function, but the volume and mass increase, reducing energy density
Solution Approach 1:
The patent removes the negative electrode active material from the battery structure, extracting only the essential components (positive electrode, separator, electrolyte) needed for lithium ion transfer. This extraction eliminates the volume and mass associated with inactive materials while maintaining battery functionality through direct lithium metal deposition on the current collector.
Solution Approach 2:
Instead of using a negative electrode active material that hosts lithium ions during charging and releases them during discharging, the patent inverts the approach by directly depositing lithium metal on the current collector during charging. This inversion eliminates the need for hosting materials and maximizes energy density.
2Quantity of substance
If no negative electrode active material is used, then energy density increases, but dendritic lithium metal forms on the negative electrode surface, causing short circuits and reduced capacity
Solution Approach 1:
The patent introduces a coating layer on the negative electrode current collector that acts as an intermediary between the deposited lithium metal and the electrolyte. This coating layer suppresses dendrite formation by providing a uniform deposition surface and stabilizing the solid electrolyte interface, thereby maintaining reliability while enabling high energy density.
3Ease of manufacture
If conventional negative electrode active materials are used, then the battery can be assembled with standard structures, but the volume occupation reduces the overall capacity and energy density
Solution Approach 1:
The patent extracts the negative electrode active material from the standard battery structure, leaving only the current collector. This simplification maintains ease of manufacture through standardized assembly processes while dramatically increasing battery capacity by eliminating volume occupation from inactive materials.
4Reliability
If physical pressure is applied to suppress lithium metal discrete growth, then cycle characteristic improves, but mechanical mechanisms increase weight and volume, reducing energy density
Solution Approach 1:
The patent replaces mechanical pressure mechanisms with a chemical intermediary (coating layer) that suppresses lithium metal discrete growth through surface modification and solid electrolyte interface stabilization. This eliminates the need for heavy mechanical components while maintaining cycle characteristic reliability.
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 design enhances energy density and cycle characteristics by reducing the volume and mass of the battery, suppressing dendritic lithium growth, and improving the interaction between the negative electrode and lithium ions, resulting in a more stable and efficient charging/discharging process.
Implementation Method 1
charge is performed by a direct precipitation of a new lithium metal on the lithium metal as the negative electrode active material
Implementation Method 2
discharge is performed by an electrolytic dissolution of the lithium metal
Implementation Method 3
a separation membrane and an electrolyte interposed therebetween
Data Source
AI summary
The purpose of the present invention is to provide a lithium secondary battery having a high energy density and an excellent cycle characteristic. The present invention relates to a lithium secondary battery having a positive electrode and a negative electrode not having a negative electrode active material, wherein at least a part of a surface of the negative electrode facing the positive electrode is coated with a compound containing an aromatic ring to which two or more elements selected from the group consisting of N, S, and O are each independently bonded.