SOFC Electrolyte Sheet Bonding via Adhesive Slurry
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Solution Overview
Problem
Existing methods for fabricating solid oxide fuel cells (SOFCs) at low/middle temperatures face challenges in forming dense and thin ceria-based electrolytes on porous fuel electrodes, leading to high material waste and lengthy fabrication times, especially when using pellet or tape casting processes.
Innovation Solution
A method involving the formation of a fuel electrode pellet with a pore forming agent, followed by stacking and heat-treating a sheet cell composed of fuel electrode and electrolyte sheets, using NiO and Ce-based oxides with specific surface areas, and applying adhesive slurry for adherence and heat treatment to achieve a dense electrolyte and efficient material use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If coating or dipping process is used to form electrolyte on porous fuel electrode, then electrolyte can be formed on the electrode, but it is difficult to form the electrolyte to be dense and thin due to different shrinkage between porous fuel electrode and ceria-based electrolyte
Solution Approach 1:
The fabrication process is divided into two independent stages: first forming the porous fuel electrode pellet, then separately forming the dense electrolyte sheet, and finally assembling them together. This segmentation allows each component to be optimized independently - the electrode maintains its porous structure while the electrolyte achieves dense thin-film formation without shrinkage constraints.
Solution Approach 2:
An adhesive slurry containing fuel electrode material is used as an intermediary substance between the porous fuel electrode pellet and the dense electrolyte sheet. This adhesive layer facilitates bonding between the two components with different shrinkage characteristics, enabling the assembly to withstand thermal processing while maintaining the dense and thin structure of the electrolyte.
2Manufacturing precision
If tape casting process is used to form fuel electrode and electrolyte in sheet shape, then dense electrolyte can be formed, but amount of powder wasted during fabrication is very large and fabrication time is too long
Solution Approach 1:
The invention merges the advantages of pellet process (material efficiency, speed) and tape casting process (electrolyte density) by forming the electrolyte as a dense sheet through controlled drying and sintering, then assembling it with the pellet-formed fuel electrode. This hybrid approach achieves dense electrolyte with reduced material waste and faster fabrication.
Solution Approach 2:
The invention optimizes the particle size distribution and composition of the electrolyte slurry to achieve dense packing and rapid sintering. By controlling the slurry parameters (particle size, binder content, solvent), the electrolyte sheet achieves high density with minimal material waste and reduced drying/sintering time, thereby improving productivity.
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 method allows for the adjustment of porosity in fuel electrodes, minimizes material waste, and enables high-quality, high-productivity SOFC fabrication with excellent adhesion and densification of the electrolyte, facilitating mass production.
Implementation Method 1
molding and heat-treating powder, in which a fuel electrode material is mixed with a pore forming agent, so as to prepare a fuel electrode pellet
Implementation Method 2
coating an adhesive slurry containing the fuel electrode material on the sheet cell or the pellet and adhering the fuel electrode sheet of the sheet cell and the pellet and then heat-treating it
Implementation Method 3
a refractory or heat resistant alloy is positioned at the upper side of the sheet cell and pellet adhered to each other and then the heat treatment is performed, in order to apply a pressure during the heat treatment in the step (c)
Data Source
AI summary
The present invention relates to a fabrication method of a solid oxide fuel cell. The fabrication method of a fuel electrode and electrolyte of a solid oxide fuel cell (SOFC) in which a sheet cell including a fuel electrode sheet and an electrolyte sheet is positioned at an upper side of a surface of a fuel electrode pellet, comprising steps of (a) molding and heat-treating powder, in which a fuel electrode material is mixed with a pore forming agent, so as to prepare a fuel electrode pellet; (b) stacking the fuel electrode sheet containing the fuel electrode material and the electrolyte sheet containing an electrolyte material so as to prepare the sheet cell; and (c) coating an adhesive slurry containing the fuel electrode material on the sheet cell or the pellet and adhering the fuel electrode sheet of the sheet cell and the pellet and then heat-treating it.