SOFC Interconnect Barrier Layer for Manganese Diffusion Control
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Solution Overview
Problem
Solid oxide fuel cell (SOFC) electrolyte corrosion and cracking occur due to manganese diffusion from the electrically conductive manganese containing perovskite layer on the interconnect into the ceramic electrolyte, leading to intergranular corrosion and catastrophic failure at elevated temperatures.
Innovation Solution
A barrier layer is deposited between the manganese containing perovskite layer and the glass or glass ceramic seal, and optionally between the seal and the zirconia based electrolyte, to prevent manganese diffusion and reduce or eliminate corrosion, using materials like clay, ceramic, or glass ceramic that block manganese and cobalt diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an electrically conductive manganese containing perovskite layer is used on the interconnect, then electrical conductivity is improved, but manganese diffusion to the electrolyte causes corrosion and cracking
Solution Approach 1:
A barrier layer is introduced as an intermediary between the manganese containing perovskite layer and the zirconia based electrolyte. This barrier layer prevents manganese diffusion from the perovskite layer to the electrolyte, eliminating the corrosion and cracking problem while allowing the perovskite layer to maintain its electrical conductivity function.
Solution Approach 2:
The interface between the perovskite layer and electrolyte is segmented into three distinct layers: the perovskite layer, the barrier layer, and the electrolyte. This segmentation isolates the manganese containing perovskite from direct contact with the electrolyte, preventing harmful interactions while maintaining electrical functionality.
2Reliability
If a barrier layer is added to prevent manganese diffusion, then electrolyte corrosion is reduced, but device complexity increases
Solution Approach 1:
The barrier layer is formed from composite materials including clay, ceramic, glass ceramic, or combinations thereof. These composite materials provide effective manganese diffusion barriers while maintaining compatibility with the existing perovskite and electrolyte layers, achieving protection without excessive complexity.
Solution Approach 2:
The barrier layer is applied locally at the critical interface where manganese diffusion occurs, specifically between the perovskite layer and electrolyte. This localized approach addresses the corrosion problem only where it occurs, minimizing the overall structural complexity while providing targeted protection.
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 barrier layer effectively prevents manganese diffusion, reducing or eliminating electrolyte corrosion and cracking, thereby enhancing the durability and reliability of the SOFC stack by maintaining the integrity of the zirconia based electrolyte even after extended operation at high temperatures.
Implementation Method 1
The barrier layer is configured to prevent Mn or Co diffusion from the electrically conductive metal oxide layer to the adjacent SOFC
Data Source
AI summary
A solid oxide fuel cell (SOFC) stack including a plurality of SOFCs and a plurality of interconnects. Each interconnect is located between two adjacent SOFCs, and each interconnect contains a Mn or Co containing, electrically conductive metal oxide layer on an air side of the interconnect. The SOFC stack also includes a barrier layer located between the electrically conductive metal oxide layer and an adjacent SOFC. The barrier layer is configured to prevent Mn or Co diffusion from the electrically conductive metal oxide layer to the adjacent SOFC.