Gradient Pore Anode for Solid Oxide Fuel Cell Electrolyte
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Solution Overview
Problem
The challenge is to form a dense electrolyte layer with a thickness of 1 micron or smaller on a porous electrode substrate without defects, while maintaining thermal and mechanical stability, as existing methods face issues with pore size control and sintering shrinkage differences between the substrate and electrolyte layer.
Innovation Solution
An anode-supported solid oxide fuel cell with a nano-porous layer having pores smaller than the electrolyte layer thickness is introduced, where the nano-porous layer is formed between the porous anode support and the electrolyte layer, allowing for a gradual reduction in pore size to facilitate the formation of a dense electrolyte layer without defects, using a method involving composite nano-powder slurry application, drying, and sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the thickness of the electrolyte layer is reduced to below 1 micron to lower operational temperature and improve cost-effectiveness, then energy efficiency and economic feasibility are improved, but the electrolyte layer becomes vulnerable to thermal and mechanical degradation and cannot be formed densely on existing porous substrates
Solution Approach 1:
A nano-porous intermediate layer is introduced between the porous substrate and the dense electrolyte layer. This intermediate layer acts as a mediator that bridges the structural gap between the porous substrate and the dense electrolyte, enabling the formation of a defect-free thin electrolyte layer while maintaining substrate porosity for gas transport.
Solution Approach 2:
The anode support structure is designed with spatially varying pore sizes: larger pores in the bulk region for gas transport and smaller pores at the surface region in contact with the electrolyte. This local quality variation allows simultaneous optimization of gas diffusion and electrolyte layer formation without compromising either function.
2Manufacturing precision
If the pore size of the porous substrate is reduced to enable formation of a dense electrolyte layer, then manufacturing precision of the electrolyte layer is improved, but gas transport to the electrolyte is hampered and device complexity increases
Solution Approach 1:
The anode support is segmented into functionally distinct regions: a bulk region with larger pores optimized for gas transport and a surface region with smaller pores optimized for electrolyte layer formation. This segmentation allows each region to independently fulfill its specific function without compromising the other.
Solution Approach 2:
The pore size distribution is locally optimized: larger pores in the bulk for gas diffusion and smaller pores at the surface for dense electrolyte formation. This local quality variation resolves the contradiction between gas transport efficiency and electrolyte layer density.
3Manufacturing precision
If the pore size of the porous substrate is reduced to enable formation of a dense electrolyte layer, then manufacturing precision of the electrolyte layer is improved, but device complexity and process difficulty increase
Solution Approach 1:
The anode support fabrication is segmented into two main stages: forming the bulk porous structure with larger pores for gas transport, and then creating a surface nano-porous layer with smaller pores. This segmentation simplifies the overall process by dividing the complex microstructure control into manageable steps with distinct functions.
4Strength
If a dense electrolyte layer is formed on a porous substrate with pore sizes comparable to or larger than the electrolyte thickness, then the substrate provides good mechanical support, but defects are generated in the electrolyte layer due to pores
Solution Approach 1:
The nano-porous intermediate layer serves as a mediator that decouples the mechanical support function from the gas transport function. The bulk porous substrate provides mechanical strength, while the intermediate layer with smaller pores ensures defect-free electrolyte formation, eliminating the direct conflict between substrate porosity and electrolyte density.
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 enables the formation of a dense, defect-free electrolyte layer with improved thermal and mechanical stability, enhancing the cost-effectiveness and performance of solid oxide fuel cells for both large-scale power generation and small mobile applications, while reducing operational temperature and material restrictions.
Implementation Method 1
applying a composite nano-powder slurry on a porous anode support to form a thin film, drying the thin film
Implementation Method 2
sintering the thin film to form a sintered body, at a sintering temperature of 900° C. or higher
Implementation Method 3
reducing the sintered body to form the sintered body after reduction
Data Source
AI summary
The present invention relates to a solid oxide fuel cell having a gradient structure in which pore size becomes gradually smaller from a porous electrode to an electrolyte thin film in order to form a dense electrolyte thin film of less than about 2 microns and preferably less than 1 micron on the porous electrode.