Evaporated Lithium Metal Anode Assembly With Passivation Cover Layer
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Solution Overview
Problem
Current lithium anode production methods for lithium-based batteries face challenges such as high capital investment, fire hazards, expensive materials, dendrite formation, and limited thickness due to the reactivity and physical weakness of lithium, which hinder the development of cost-effective and durable lithium metal anodes, especially for solid-state batteries.
Innovation Solution
A multi-layer lithium anode assembly is developed, comprising a substrate with a current collector, a lithium hosting region with a thin lithium film deposited via thermal evaporation, and a cover region with a passivation or lithiophilic material to inhibit irreversible reactions and dendrite formation, allowing for improved plating and stripping characteristics without the need for lithium foil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium foil is used as anode material, then high capacity is achieved, but handling difficulty and self-adhesion increase
Solution Approach 1:
The anode is segmented into multiple functional layers: current collector, buffer layer, lithium-containing layer, and protective layer. This segmentation allows each layer to perform its specific function while collectively solving the handling difficulties of pure lithium foil.
Solution Approach 2:
The anode uses a composite structure combining different materials (current collector material, buffer material, lithium compound, protective material) to achieve both high lithium capacity and improved mechanical properties for easier handling.
2Quantity of substance
If lithium foil thickness is reduced, then energy density improves, but mechanical strength decreases
Solution Approach 1:
The anode structure segments the lithium-containing function into a specific layer with controlled thickness, supported by thicker current collector and protective layers, enabling thin lithium content while maintaining overall mechanical strength.
Solution Approach 2:
The anode uses thin film structures for the lithium-containing layer (reducing thickness to improve energy density) while relying on the current collector and protective layers to provide the necessary mechanical strength and flexibility.
3Ease of manufacture
If conventional anode manufacturing is used, then production is simple, but capital investment and material costs increase
Solution Approach 1:
The current collector serves multiple functions: structural support, electrical conductivity, and anchoring for the lithium-containing layer. The protective layer provides both mechanical protection and chemical stability. This multi-functionality reduces the need for additional components and simplifies manufacturing while controlling costs.
4Weight of moving object
If lithium anode is made thinner, then battery weight decreases, but dendrite formation increases
Solution Approach 1:
The anode structure provides different local properties: the buffer layer offers a controlled interface for lithium deposition, the lithium-containing layer provides the active material with specific thickness, and the protective layer offers chemical stability. This local differentiation allows thin overall structure while preventing dendrites through controlled lithium ion transport pathways.
Solution Approach 2:
The buffer layer and protective layer act as intermediaries between the lithium-containing layer and the electrolyte, controlling lithium ion deposition and preventing direct contact that would cause dendrite formation, while allowing the lithium layer to remain thin for reduced weight.
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 multi-layer anode assembly reduces production costs, enhances durability, and prevents dendrite formation, thereby improving the performance and cycle life of lithium-based batteries while maintaining a thin and lightweight design suitable for both liquid and solid-state batteries.
Implementation Method 1
a lithium material film deposited directly onto the support surface via thermal evaporation
Implementation Method 2
A cover region outboard of the lithium hosting region and including at least one cover film formed from a passivation material that allows a lithium ion flux
Data Source
AI summary
A multi-layer, lithium anode assembly for use in a lithium-based battery can include a substrate region having a current collector comprising a continuous copper foil that is between 4 and 10 microns thick and has a lithium compatible support surface. A lithium hosting region may overlie the support surface and may include a lithium material film deposited directly onto the support surface via thermal evaporation and having a thickness that is between 1 microns and 10 microns. A cover region may be located outboard of the lithium hosting region and may have a cover film that is formed from a passivation material and covers the lithium material film. The cover region may allow a lithium ion flux between an electrolyte and the lithium hosting region and inhibiting irreversible reactions between the lithium hosting region and the electrolyte or surrounding environment.