3D Lithium Anode Capping Layer for Dendrite Suppression

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Solution Overview

Problem

Current lithium-ion battery anodes based on graphite have limited capacity, leading to increased size and weight issues, particularly in electric vehicles, and lithium metal anodes face reactivity, dendritic growth, volume changes, and limited life cycles.

Innovation Solution

A three-dimensional lithium anode with a capping layer is developed using arc discharge or electron beam evaporation of Li2O, combined with a conformal capping layer formed by materials like carbon, LLZO, or LIPON, which suppresses dendritic growth and enhances lithium ion diffusion, and a columnar structure is achieved through controlled deposition processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If graphite anode is used, then battery capacity is limited, but battery size and weight can be reduced

Engineering Contradiction:

Improvebattery capacityVSAvoidbattery weight

Core Design Contradiction:

Quantity of substanceVSWeight of stationary object

Solution Approach 1:

The patent changes the anode material from graphite to lithium metal, fundamentally altering the capacity parameter. Lithium metal provides a theoretical capacity of 3860 mAh/g compared to graphite's limited capacity, enabling higher energy density without proportionally increasing weight

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure combining lithium metal with a capping layer (graphite, LLZO, or LIPON). This composite approach maintains the high capacity benefit of lithium metal while mitigating its disadvantages through the protective and functional properties of the capping layer

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If lithium metal anode is used, then battery capacity increases, but dendritic growth occurs

Engineering Contradiction:

Improvebattery capacityVSAvoidanode stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The capping layer acts as an intermediary between the lithium metal and the electrolyte. It allows lithium ion diffusion while preventing direct contact that would cause dendritic growth. The layer mediates the interaction, enabling high capacity while maintaining reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The capping layer is applied in advance to prevent dendritic growth before it can occur. By establishing a protective barrier prior to battery operation, the system preemptively counteracts the tendency of lithium to form dendrites

Inventive Principle:

Principle #9Preliminary anti-action

3Quantity of substance

If lithium metal anode is used, then battery capacity increases, but reactivity with air and water increases

Engineering Contradiction:

Improvebattery capacityVSAvoidsurface degradation

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The capping layer serves as a protective intermediary that shields the highly reactive lithium metal from exposure to air and water. It allows ionic conduction while providing a barrier against harmful environmental factors that would otherwise degrade the lithium surface

Inventive Principle:

Principle #24Intermediary (Mediator)

4Quantity of substance

If lithium metal anode is used, then battery capacity increases, but volume changes increase

Engineering Contradiction:

Improvebattery capacityVSAvoidanode stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The capping layer acts as a flexible protective shell that can accommodate volume changes of the lithium metal during charge-discharge cycles. This thin film structure maintains anode stability while allowing the underlying lithium to expand and contract

Inventive Principle:

Principle #30Flexible shells and thin films

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 solution increases lithium-ion battery capacity without weight or size increases, stabilizes the anode, and reduces dendritic growth, while the conformal capping layer provides protection and potentially eliminates the need for a separate separator.

Implementation Method 1

Li2O is used as target material to perform arc discharge and/or ebeam (electron beam) evaporation

Methodology Applied

Scientific EffectArc discharge: Electric Arc

Implementation Method 2

Li2O is used as target material to perform arc discharge and/or ebeam (electron beam) evaporation

Methodology Applied

Scientific EffectElectron beam evaporation: Electron Beam

Implementation Method 3

Introducing a reactive gas X into the reaction chamber and with the help of the high energy impact of the arc discharge and/or ebeam evaporation, the Li2O is insitu reduced to Li2 and XO

Methodology Applied

Scientific EffectIn-situ reduction: Reduction

Implementation Method 4

Lithium ions then diffuse through this layer and add to the interface without showing dendritic growth

Methodology Applied

Scientific EffectLithium ion diffusion: Diffusion

Data Source

PatentUS20240170738A1Three dimensional lithium anode with a capping layer

Publication Date: 2024.05.23 OERLIKON SURFACE SOLUTIONS AG PFAFFIKON

AI summary

A battery half-cell comprising a copper foil, a lithium anode layer deposited on a surface of the copper foil and a capping layer, preferably a conformal capping layer, deposited on the lithium anode layer. The lithium anode layer comprises vertical structures such as columnar structures and/or grid structures.