SOFC Anode Substrate Using 3YSZ Composite

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Solution Overview

Problem

Conventional solid oxide fuel cell membrane electrode assemblies face issues with mechanical strength and durability during reduction-oxidation and thermal cycling, leading to packaging failures and limited power output due to the thickness of the anode substrate.

Innovation Solution

A membrane electrode assembly structure using NiO, 8YSZ, and 3YSZ materials for the anode substrate, with a method involving tape casting, sintering, and the addition of a porous LSM cathode layer to enhance mechanical strength and reduce substrate thickness, thereby improving conductivity and gas diffusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the thickness of the anode substrate is reduced to increase power density, then the power output is improved, but the mechanical strength decreases causing cracking during packaging

Engineering Contradiction:

Improvepower densityVSAvoidmechanical strength

Core Design Contradiction:

PowerVSStrength

Solution Approach 1:

The patent uses a composite material system consisting of NiO-8YSZ anode supported cell combined with 3YSZ (tetragonal zirconia) as a strengthening phase. The 3YSZ is exploited after calcination to enhance the toughness and mechanical strength of the NiO-8YSZ anode substrate, allowing the substrate thickness to be reduced while maintaining sufficient mechanical strength to prevent cracking during packaging and testing.

Inventive Principle:

Principle #40Composite materials

2Productivity

If the porosity of cathode and anode is increased to facilitate gas-solid reaction, then the reaction efficiency is improved, but the mechanical strength is sacrificed leading to packaging failure

Engineering Contradiction:

Improvegas-solid reaction efficiencyVSAvoidmechanical strength

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The patent employs a composite material approach where 3YSZ is added to the NiO-8YSZ anode substrate to create a mechanically stronger composite structure. This composite material maintains the necessary porosity for gas-solid reaction while providing enhanced mechanical strength to prevent packaging failure.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If the electrolyte layer thickness is increased to reduce manufacturing complexity, then the manufacturing process is simplified, but the bulk impedance increases requiring higher operating temperature

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidoperating temperature

Core Design Contradiction:

Ease of manufactureVSTemperature

Solution Approach 1:

The patent utilizes parameter changes by exploiting the crystal phase transformation of zirconia from monoclinic to tetragonal phase through calcination. The 3YSZ (tetragonal zirconia) provides enhanced mechanical properties and ionic conductivity, allowing for optimized electrolyte thickness and reduced operating temperature while maintaining manufacturing feasibility.

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 solution results in a high-strength anode substrate with reduced thickness, enhancing the fuel cell's power density and durability, with a 15% increase in power efficiency and minimal decay after 1,000 hours of operation.

Implementation Method 1

the 3YSZ is a material of tetragonal crystal phase exploited after calcinations to enhance the toughness and mechanical strength of material NiO-8YSZ

Methodology Applied

Scientific EffectSolid solution strengthening: Solid Solution Strengthening

Implementation Method 2

which can moderately reduce the fuel gas diffusion path and resistance, and thus effectively improve the conductivity at the anode side

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 3

forming a slurry composed of NiO-8YSZ-3YSZ into an anode green tape by tape casting

Methodology Applied

Scientific EffectTape casting:

Implementation Method 4

followed by using a thin film ceramic process and a high temperature densification sintering process to produce a half-cell substrate

Methodology Applied

Scientific EffectSintering: Sintering

Data Source

PatentUS10283799B2Membrane electrode assembly structure of fuel cell and the method of fabricating the same

Publication Date: 2019.05.07 ATOMIC ENERGY COUNCIL INSTITUTE OF NUCLEAR ENERGY RESEARCH

AI summary

A membrane electrode assembly structure of a fuel cell and a method of making the same are disclosed. The materials to be used include NiO, 8YSZ and 3YSZ that mixed into a slurry, formed into anodes by tape casting, sintered to form an anode substrate, and followed by forming a thin film of electrolyte layer on the surface of the anode substrate, forming a cathode layer on the outer surface of the electrolyte layer to obtain the membrane electrode assembly, which utilizes the 3YSZ having a tetragonal crystal phase to improve the toughness and mechanical strength of the material of NiO-8YSZ through calcination, thus the thickness of the anode substrate can be reduced, and the fuel gas diffusion path and resistance can be appropriately reduced to enhance the conductivity of the anode substrate.