SOFC Electrode Composite Oxide Slurry for Uniform Powder Dispersion

Solution Overview

Problem

In the production of metal composite oxides for solid oxide fuel cells, the dispersion of metal compound powders in a slurry often leads to settling and aggregation, resulting in uneven distribution and difficulty in achieving a desired composition due to high specific gravity and particle size variations, which affects the uniformity and adhesion of the electrode layers.

Innovation Solution

A method involving the use of a polyalkylene oxide with a viscosity average molecular weight of 150,000 or more as a dispersant, combined with a dispersion medium and a planetary ball mill, to create a stable slurry with controlled viscosity, preventing settling and aggregation of metal compounds, and ensuring uniform dispersion, followed by baking to obtain a metal composite oxide with a perovskite-type crystal structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If metal compound powders are dispersed in a slurry for electrode production, then the electrode can be formed, but the powders settle and aggregate due to high specific gravity and particle size variations, resulting in uneven distribution and difficulty achieving desired composition

Engineering Contradiction:

Improvecomposition uniformityVSAvoidslurry stability

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

A polymer dispersant with specific molecular weight (100,000-1,000,000) is introduced as an intermediary substance between metal compound powders and slurry. This dispersant adsorbs onto particle surfaces, providing steric stabilization that prevents aggregation and settling, thereby maintaining both slurry stability and composition uniformity throughout the electrode production process

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The molecular weight of the polymer dispersant is optimized within a specific range (100,000-1,000,000). This parameter change ensures the dispersant has sufficient chain length to provide effective steric barrier while maintaining appropriate solution viscosity, resolving the contradiction between preventing particle settling and achieving uniform composition distribution

Inventive Principle:

Principle #35Parameter changes

2Productivity

If conventional dispersants are used to disperse metal compound powders, then the slurry can be prepared, but aggregation occurs forming hard precipitates that are difficult to re-disperse, affecting productivity

Engineering Contradiction:

Improveproduction efficiencyVSAvoiddispersion stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

A polymer dispersant with specific molecular weight (100,000-1,000,000) is introduced as an intermediary substance between metal compound powders and slurry. This dispersant adsorbs onto particle surfaces, providing steric stabilization that prevents aggregation and settling, thereby maintaining both slurry stability and composition uniformity throughout the electrode production process

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The molecular weight of the polymer dispersant is optimized within a specific range (100,000-1,000,000). This parameter change ensures the dispersant has sufficient chain length to provide effective steric barrier while maintaining appropriate solution viscosity, resolving the contradiction between preventing particle settling and achieving uniform composition distribution

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

This approach results in a uniformly dispersed slurry that maintains the desired composition of metal composite oxides, enhancing the adhesion of the electrode to other layers and improving the productivity by preventing clogging, and achieving a stable perovskite-type crystal structure, thus improving the performance and durability of solid oxide fuel cells.

Implementation Method 1

the slurry further includes a polyalkylene oxide having a viscosity average molecular weight of 150,000 or more

Methodology Applied

Scientific EffectSteric stabilization:

Implementation Method 2

combined with a dispersion medium and a planetary ball mill, to create a stable slurry

Methodology Applied

Scientific EffectMechanical force: Mechanical Force

Implementation Method 3

followed by baking to obtain a metal composite oxide with a perovskite-type crystal structure

Methodology Applied

Scientific EffectSintering: Sintering

Data Source

PatentUS12148934B2Metal composite oxide and production method thereof, and electrode for solid oxide fuel cell

Publication Date: 2024.11.19 SAKAI CHEM IND CO LTD

AI summary

A method for producing a metal composite oxide, the method including steps of: preparing a slurry by mixing different kinds of metal compounds in a powder form, a dispersion medium, and a dispersant, and baking the different kinds of metal compounds after the dispersion medium in the slurry is removed. The slurry further includes a polyalkylene oxide having a viscosity average molecular weight of 150,000 or more. The slurry has a viscosity of 10 mPa·s to 2000 mPa·s, the viscosity being measured using a B-type viscometer under conditions of a temperature of 23° C. to 27° C. and a rotation rate of 60 rpm. According to the production method, a slurry in which different kinds metal compound powders are uniformly dispersed and a precipitate is unlikely to be formed can be obtained. Therefore, a metal composite oxide having a desired composition can be obtained.