Lithium Alloy Anode Wetting for Stronger Current Collector Adhesion

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Solution Overview

Problem

Lithium metal batteries face performance issues due to weak adhesion of lithium metal to the current collector, leading to increased resistance and impedance over time, which diminishes their electrochemical cell lifetime.

Innovation Solution

A method of forming a lithium alloy anode by melting solid lithium and adding a surface tension reduction agent such as silver, tin, gallium, indium, or zinc to create a melt that spontaneously wets the current collector, eliminating the need for lithiophilic coatings and improving adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If lithium metal is used as the negative electrode to achieve high theoretical capacity and lowest electrochemical potential, then energy density is improved and storage capacity is doubled, but adhesion to the current collector deteriorates leading to increased resistance and impedance over time

Engineering Contradiction:

Improveenergy densityVSAvoidadhesion to current collector

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

A lithium alloy layer containing 5-20 atomic percent of a second metal (silver, tin, gallium, indium, or zinc) is introduced as an intermediary between the lithium metal and the current collector. This alloy layer improves adhesion and reduces resistance/impedance increases over time while maintaining the high energy density benefits of lithium metal, effectively mediating the interface between the electrode and collector.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The negative electrode is constructed as a composite structure with a lithium alloy layer (5-20 at% second metal) on the current collector. This composite approach combines the high capacity of lithium with the adhesion benefits of the second metal, resolving the contradiction between energy density and reliability.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If lithium metal is used as the negative electrode to achieve high theoretical capacity, then storage capacity is doubled, but electrochemical cell lifetime deteriorates due to weak long-term adhesion

Engineering Contradiction:

Improvestorage capacityVSAvoidelectrochemical cell lifetime

Core Design Contradiction:

Quantity of substanceVSDuration of action of stationary object

Solution Approach 1:

The lithium alloy layer serves as a mediator that preserves the high storage capacity of lithium metal while extending electrochemical cell lifetime by preventing weak adhesion issues. The 5-20 at% second metal content optimizes both capacity retention and long-term adhesion performance.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The composition of the lithium alloy layer is precisely controlled at 5-20 atomic percent second metal to optimize the balance between storage capacity and electrochemical cell lifetime. This parameter optimization ensures high capacity while preventing adhesion degradation over time.

Inventive Principle:

Principle #35Parameter changes

3Power

If conventional lithium metal anodes are used, then high energy density is achieved, but resistance and impedance increase over time due to poor adhesion

Engineering Contradiction:

Improveenergy densityVSAvoidresistance and impedance increase

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The lithium alloy layer with 5-20 at% second metal acts as a protective intermediary that maintains high energy density while preventing the harmful increase in resistance and impedance over time. The alloy composition is optimized to ensure low resistance growth during cycling.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 of the lithium alloy to the current collector, resulting in improved performance and extended battery lifetime by reducing surface tension and allowing for uniform wetting without additional surface treatments.

Implementation Method 1

forming a melt comprising lithium and a surface tension reduction agent

Methodology Applied

Scientific EffectSurface tension reduction: Surface Tension

Implementation Method 2

a layer of the melt wets onto the anode current collector to form the anode

Methodology Applied

Scientific EffectWetting: Wetting

Data Source

PatentUS20250105269A1Lithium alloy anode

Publication Date: 2025.03.27 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

Methods for fabricating an anode, methods for fabricating a battery, and lithium batteries are disclosed. A method for fabricating an anode includes forming a melt comprising lithium and a surface tension reduction agent, wherein the surface tension reduction agent is selected from the group consisting of silver, tin, gallium, indium, zinc, and combinations thereof; and contacting an anode current collector with the melt, wherein a layer of the melt wets onto the anode current collector to form the anode as a lithium alloy.