Lithium Intermetallic Intermediate Layer for Current Collector Adhesion
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Solution Overview
Problem
Lithium metal batteries face issues with interfacial instability and weak adhesion between the lithium metal and the metal current collector, leading to undesirable side reactions and increased resistance and impedance during cell cycling.
Innovation Solution
A lithium-based electrode assembly is formed by coating a metal current collector with an intermediate layer comprising a lithium intermetallic compound, such as Li4Ag, Li9Al4, or Li17Sn4, and then depositing a lithium metal layer on top, with heat and pressure applied to form a strong bond between the lithium metal and the current collector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is directly deposited on the metal current collector, then the battery achieves high energy density, but the adhesion between lithium metal and current collector becomes weak
Solution Approach 1:
An intermediate layer comprising a lithium intermetallic compound is introduced between the lithium metal electrode and the metal current collector. This intermediate layer acts as a mediator that provides strong adhesion to the current collector while maintaining compatibility with the lithium metal, thereby resolving the adhesion weakness without compromising energy density.
2Use of energy by moving object
If lithium metal is directly deposited on the metal current collector, then the battery achieves high energy density, but interfacial instability occurs leading to side reactions
Solution Approach 1:
The lithium intermetallic compound intermediate layer serves as a protective intermediary that stabilizes the interface between lithium metal and the current collector. This intermediate layer prevents direct contact and unwanted side reactions between the lithium metal and the current collector or electrolyte, thereby improving interfacial stability and reliability while preserving high energy density.
3Strength
If an intermediate layer is added between lithium metal and current collector, then adhesion and stability are improved, but the device structure becomes more complex
Solution Approach 1:
The intermediate layer is formed by creating a lithium intermetallic compound, which is a composite material combining lithium with another metal element. This composite structure provides both strong adhesion and interfacial stability, achieving the desired performance improvement without significantly increasing structural complexity since the intermediate layer can be integrated into the existing electrode architecture.
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 method enhances the adhesion between the lithium metal and the current collector, reducing side reactions and maintaining long-term stability, thereby improving the performance and cycle life of lithium metal batteries.
Implementation Method 1
forming a lithium intermetallic compound including lithium metal from the electrode and the metal of the intermediate layer
Implementation Method 2
with heat and pressure applied to form a strong bond between the lithium metal and the current collector
Implementation Method 3
coating a surface of a metal current collector with an intermediate layer
Data Source
AI summary
A lithium-based electrode assembly and methods of formation relating thereto are provided. The lithium-based electrode assembly comprises a metal current collector, an electrode comprising lithium metal, and an intermediate layer disposed therebetween. The intermediate layer comprising an intermetallic compound comprising the lithium metal of the electrode and a metal selected from the group consisting of: aluminum, silver, gold, barium, bismuth, boron, calcium, cadmium, carbon, gallium, germanium, mercury, indium, iridium, lead, palladium, platinum, rhodium, antimony, selenium, silicon, tin, strontium, sulfur, tellurium, zinc, and combinations thereof. The method of forming the lithium assembly includes coating a surface of the metal current collector with the intermediate layer; disposing the electrode onto an exposed surface of the intermediate layer; and heating the electrode, the intermediate layer, and the metal current collector to form the lithium intermetallic compound, which joins the metal current collector and the electrode together.