Aqueous Ink Composition for 3D Printed Fuel Cells

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Solution Overview

Problem

Conventional methods for fabricating solid oxide fuel cells and electrolyzers result in poorly reproducible structures and porosities due to limitations in microstructural engineering, particularly in forming stable aqueous ink compositions for 3D inkjet printing, which affects the electrochemical performance.

Innovation Solution

Development of an aqueous ink composition comprising yttria-stabilized zirconia, gadolinium-doped ceria, or their mixtures, with an electrostatic dispersant, polymeric binder, and non-ionic surfactant, optimized for high reproducibility and stability to enable 3D printing of functional layers with controlled triple phase boundaries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If aqueous solvent is used instead of organic solvent, then environmental impact and cost are improved, but dispersion stability and printability deteriorate due to high surface tension

Engineering Contradiction:
Improveenvironmental impactVSAvoiddispersion stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

Aqueous surfactants are introduced as intermediary substances to mediate between the aqueous solvent and ceramic particles. These surfactants adsorb at the particle-solvent interface, reducing surface tension and enabling stable dispersion of particles in water-based solvent, thus resolving the contradiction between environmental benefits of aqueous solvents and the stability issues caused by high surface tension

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The surface tension parameter of the aqueous solvent is modified by adding surfactants. This changes the physical-chemical parameters of the ink composition, allowing water (naturally high surface tension) to behave like organic solvents (lower surface tension) in terms of printability and droplet formation, while maintaining the environmental advantages of aqueous-based formulation

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If aqueous solvent is used, then environmental impact is improved, but cracking during drying worsens due to capillary effects

Engineering Contradiction:
Improveenvironmental impactVSAvoidstructural integrity
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

Aqueous surfactants act as intermediaries that modify capillary pressure effects during drying. By adsorbing at the liquid-air interface and within the porous structure, they reduce surface tension and mitigate capillary stresses that cause cracking, enabling aqueous inks to form crack-free films despite water's high surface tension

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The surfactant provides beforehand cushioning against capillary stresses by pre-establishing a protective interface layer. This anticipatory protection prevents cracking before it occurs during the drying process, allowing the use of environmentally friendly aqueous solvents without compromising structural integrity

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Ease of manufacture

If conventional fabrication methods are used, then manufacturing simplicity is maintained, but microstructural control and reproducibility deteriorate

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidmicrostructural control
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

Conventional mechanical fabrication methods (tape casting, screen printing, manual sintering) are replaced with digital inkjet printing technology. This substitution enables precise digital control of material deposition, allowing complex 3D microstructures with controlled porosity and triple phase boundaries to be fabricated with high reproducibility, while maintaining ease of manufacture through automated printing processes

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Ease of operation

If organic-based ink is used, then printability is improved, but electrochemical performance deteriorates due to porosity from high organics content

Engineering Contradiction:
ImproveprintabilityVSAvoidelectrochemical performance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The fundamental parameter change is switching from organic to aqueous solvent base. By carefully controlling the aqueous formulation with surfactants and dispersants, the ink achieves adequate printability (droplet ejection, spreading, and pattern formation) while eliminating the porosity issues associated with organic content, thereby improving electrochemical performance through denser, more reliable microstructures

Inventive Principle:
Principle #35Parameter changes

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 ink composition allows for the reproducible fabrication of 3D scaffolds with improved electrochemical performance by ensuring stability and printability, reducing cracking and porosity, and enhancing the electrochemical performance of solid oxide fuel cells and electrolyzers.

Implementation Method 1

a dispersant, wherein the dispersant is an electrostatic dispersant

Methodology Applied
Scientific EffectElectrostatic repulsion: Ion Repulsion/Attraction

Implementation Method 2

a non-ionic surfactant... due to capillary effects arising from the comparatively high surface tension of water

Methodology Applied
Scientific EffectSurface tension reduction: Surfactant

Implementation Method 3

a polymeric binder

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 4

3D inkjet printing... reproducible ejection of droplets

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3476002B1Aqueous ink compositions
Publication Date: 2024.02.14 FARANDOS NICHOLAS
  • EP3476002B1 patent drawingFigure 1~2(e)
  • EP3476002B1 patent drawingFigure 3~3(d)
  • EP3476002B1 patent drawingFigure 4~5

AI summary

This invention relates to aqueous ink compositions comprising an aqueous solvent, particles comprising a metal or a metal compound or a mixture thereof, a dispersant, preferably selected from an electrostatic dispersant, a steric dispersant, an ionic dispersant, a non-ionic dispersant or a combination thereof, a polymeric binder and a non-ionic surfactant which may be used for 3D inkjet printing components, primarily for high- temperature electrochemical devices..