Composite Particle Powder for Solid Oxide Cell Electrodes

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Solution Overview

Problem

Current solid oxide cells face challenges in achieving high current density due to high electrode resistance, which hinders their efficiency and commercialization, despite previous research efforts to reduce this resistance.

Innovation Solution

A composite particle powder is developed, comprising electron-conducting and ion-conducting materials with specific particle size distributions and BET specific surface areas, agglomerated together to form electrodes with reduced resistance, allowing for higher current density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrode materials are used, then the electrode resistance is reduced to some extent, but the current density remains insufficient for commercialization

Engineering Contradiction:
Improveelectrode resistanceVSAvoidcurrent density
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent uses composite particle powder comprising both electron-conducting materials (such as perovskite oxides) and ion-conducting materials (such as stabilized zirconia) in specific weight ratios (electron-conducting material: 30-70 wt%, ion-conducting material: 30-70 wt%). This composite structure creates synergistic effects where electron conduction and ion conduction pathways coexist within the same electrode particles, enabling simultaneously low electrode resistance and high current density that cannot be achieved with single-material electrodes.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent controls the particle size distribution of the composite particle powder with D50 (volume-based 50% particle diameter) in the range of 0.5-2.0 μm and D75/D25 ratio of 1.2-2.0. This specific particle size distribution creates optimal local structures within the electrode: fine particles provide high surface area for electrochemical reactions, while the controlled size distribution ensures proper packing density and pore structure, creating locally optimized conditions for both electron transport and ion transport throughout the electrode.

Inventive Principle:
Principle #3Local quality

2Productivity

If electrode resistance is reduced through material compounding, then current density improves, but further higher current density is needed for early spread and commercialization

Engineering Contradiction:
Improvecurrent densityVSAvoidelectrode resistance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent optimizes multiple parameters simultaneously: (1) weight ratio parameters of electron-conducting and ion-conducting materials (30-70 wt% each), (2) particle size parameters (D50: 0.5-2.0 μm, D75/D25: 1.2-2.0), and (3) BET specific surface area parameters (0.5-5.0 m²/g). By coordinating optimization of these interrelated parameters, the patent achieves a breakthrough in current density that exceeds previous single-parameter optimization approaches, enabling commercialization-ready performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent prepares composite particle powder with predetermined composition ratios and particle size distributions before electrode fabrication. This preliminary preparation ensures that the optimal mixture of electron-conducting and ion-conducting materials is already established at the particle level, creating pre-optimized building blocks that directly form high-performance electrodes without requiring complex post-processing or sintering adjustments, thus achieving record-high current densities.

Inventive Principle:
Principle #10Preliminary action

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 composite particle powder significantly reduces electrode resistance, enabling solid oxide cells to achieve higher current densities and improve their performance and cost-effectiveness.

Implementation Method 1

a composite particle powder comprising an electron-conducting material and an ion-conducting material that are agglomerated together

Methodology Applied
Scientific EffectAgglomeration:

Data Source

PatentEP3537524B1Composite particle powder, electrode material for solid oxide cell, and electrode for solid oxide cell made thereof
Publication Date: 2022.01.19 NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE & TECHNOLOGY
  • EP3537524B1 patent drawingFigure 1

AI summary

A composite particle powder comprises an electron-conducting material and an ion-conducting material that are agglomerated together; the composite particle powder having a volume-based 50% particle diameter (D50) of 0.1 to 2.0 µm in particle size distribution measurement, a volume-based D75/D25 of 1.1 to 2.2 in particle size distribution measurement, D50 and a BET specific surface that satisfy the following: (I) in the case of 0.1 µm ≤ D50 ≤ 0.5 µm, larger than 20 m2/g and 200 m2/g or less; (II) in the case of 0.5 µm < D50 ≤ 0.9 µm, larger than 4 m2/g and 50 m2/g or less; (III) in the case of 0.9 µm < D50 ≤ 1.3 µm, larger than 2.5 m2/g and 30 m2/g or less; and (IV) in the case of 1.3 µm < D50 ≤ 2.0 µm, larger than 2 m2/g and 20 m2/g or less; and an ion-conducting material content of 35 to 75 mass%. According to the present invention, an electrode having a low electrode resistance can be provided using an oxide or a metal as a raw material.