Mesoporous Nanoionic Catalyst for SOFC Cathode Chromium Tolerance

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Solution Overview

Problem

Solid oxide fuel cells (SOFCs) face inefficiencies due to impurity formation, reduced electronic and ionic transport, and chromium poisoning, which limits their long-term operation and power density, especially at lower temperatures.

Innovation Solution

A structured anode for SOFCs incorporating a composite cathode with a yttria stabilized zirconia (YSZ) structure, a mesoporous nanoionic catalyst material, and mesoporous getter layers to enhance ionic and electronic conduction, increase gas transport surface area, and mitigate chromium poisoning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional cathode structures are used in SOFCs, then the device is simpler to manufacture, but power density and chromium tolerance are reduced

Engineering Contradiction:

Improvechromium toleranceVSAvoidcathode structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The cathode incorporates a mesoporous nanoionic catalyst material layer with controlled porosity (pore size 2-50 nm) that provides both high surface area for electrochemical reactions and efficient chromium vapor collection, resolving the contradiction between simplicity and performance by using naturally porous nanomaterials

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The cathode uses composite structures combining YSZ (yttria stabilized zirconia) with mesoporous nanoionic catalyst materials and getter layers, creating a multi-functional composite that simultaneously provides ionic conduction, catalysis, and chromium tolerance without requiring complex assembly

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If operating temperature is reduced in SOFCs, then energy efficiency improves, but chromium poisoning and impurity formation increase

Engineering Contradiction:

Improveenergy efficiencyVSAvoidchromium poisoning

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The mesoporous getter layers are incorporated into the cathode structure before operation to proactively collect and trap chromium vapor as it forms, preventing chromium poisoning before it can degrade performance, thereby enabling lower temperature operation without the usual chromium poisoning problems

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The mesoporous structure with 2-50 nm pores provides high surface area for chromium vapor adsorption while maintaining ion transport pathways, allowing effective chromium mitigation at lower operating temperatures where chromium volatility is increased

Inventive Principle:

Principle #31Porous materials

3Power

If mesoporous nanoionic catalyst material is added to the cathode, then power density and reaction zone increase, but manufacturing complexity increases

Engineering Contradiction:

Improvepower densityVSAvoidcathode fabrication

Core Design Contradiction:

PowerVSEase of manufacture

Solution Approach 1:

The invention merges multiple functions into a single integrated mesoporous nanoionic catalyst material layer that simultaneously provides catalytic activity, ionic conduction, and chromium vapor collection, reducing manufacturing steps compared to applying separate layers for each function

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The mesoporous nanoionic catalyst material serves multiple functions at once: it acts as a catalyst for electrochemical reactions, provides ionic conduction pathways, and functions as a getter layer for chromium vapor, simplifying the overall cathode structure despite enhanced performance

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 improves the power density and thermal stability of SOFCs by increasing the reaction zone, reducing overpotentials, and enhancing chromium tolerance, thereby extending the cell's operational lifespan and reliability.

Implementation Method 1

enhance ionic and electronic conduction

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

enhance ionic and electronic conduction

Methodology Applied

Scientific EffectElectronic conduction: Conduction (electrical)

Implementation Method 3

mesoporous nanoionic catalyst material

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 4

collect chromium (Cr) vapor and mitigate the effects of Cr-poisoning

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentUS10411267B2Highly porous cathode catalyst layer structures for flexible solid oxide fuel cell applications in vehicles

Publication Date: 2019.09.10 NISSAN MOTOR CO LTD

AI summary

A solid oxide fuel cell (SOFC) includes a cathode having a yttria stabilized zirconia (YSZ) structure. The YSZ structure is in contact with a solid electrolyte layer. A lanthanum strontium manganite (LSM) structure is deposited on the YSZ structure to form a composite cathode. The cathode includes a catalyst layer. The catalyst layer is a mesoporous nanoionic catalyst material integrated with the YSZ and LSM structures. Alternatively, or in addition to, the mesoporous nanoionic catalyst material may be coated onto the YSZ and LSM structures or embedded into the YSZ and LSM structures. The mesoporous nanoionic catalyst material may form an interconnected fibrous network.