Spinel Bonding Layer for Solid Oxide Fuel Cell Interconnects
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Solution Overview
Problem
Existing solid oxide fuel cell technologies face challenges in achieving sufficient bonding strength between electrodes and conductive connection members at temperatures below 1,000°C, leading to reduced power generation performance and increased risk of breakage due to insufficient sintering or oxidation of metallic interconnectors.
Innovation Solution
A bonding layer composed of a transition metal oxide with a spinel structure, such as MnCo2O4 or CuMn2O4, is used to bond the electrodes and conductive connection members, providing adequate mechanical strength and electrical conductivity while preventing oxidation, and is applied using a paste that is fired at temperatures between 500°C to 900°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermal treatment is carried out at high temperature (1,000°C or higher) to achieve sufficient bonding strength, then bonding strength is improved, but the metallic interconnector is oxidized and resistance increases
Solution Approach 1:
A bonding layer composed of a transition metal oxide with a spinel structure (such as MnCo2O4 or CuMn2O4) is introduced as an intermediary between the electrode and the conductive connection member. This bonding layer enables sufficient bonding strength to be achieved at lower thermal treatment temperatures (500-900°C), thereby preventing oxidation of the metallic interconnector while maintaining adequate bonding strength.
2Object-affected harmful factors
If thermal treatment is carried out at low temperature (800 to 900°C) to prevent oxidation, then oxidation is suppressed, but the bonding layer is insufficiently sintered and bonding strength is insufficient
Solution Approach 1:
The invention changes the material parameters of the bonding layer by using a transition metal oxide with a spinel structure, which has specific properties that enable adequate sintering and bonding strength at lower temperatures (500-900°C). This parameter change allows the bonding process to occur at temperatures that prevent interconnector oxidation while still achieving sufficient bonding strength.
3Ease of manufacture
If expensive materials like silver are used in the bonding layer to improve sinterability at low temperature, then sinterability and suppression of oxidation are improved, but cost increases
Solution Approach 1:
The invention replaces expensive materials like silver with a transition metal oxide having a spinel structure (such as MnCo2O4 or CuMn2O4), which is significantly cheaper. This substitution maintains the ability to achieve adequate bonding strength at lower temperatures without the high cost associated with noble metals, making the process economically viable.
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 achieves strong bonding between electrodes and conductive connection members, enhancing power generation output and reducing internal resistance, while maintaining cost-effectiveness by avoiding the use of expensive materials like silver.
Implementation Method 1
thermal treatment carried out at a temperature lower than 1,000°C
Implementation Method 2
preventing oxidation
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
The present invention provides an electrochemical device including electrodes of an electrochemical cell and conductive connection members, wherein sufficient bonding strength is achieved between each of the electrodes and the corresponding conductive connection member through thermal treatment carried out at a temperature lower than 1,000°C. The electrochemical cell includes a solid electrolyte membrane and a pair of electrodes provided on the electrolyte membrane. The conductive connection members are electrically connected to the respective electrodes by means of a bonding layer. The bonding layer contains a transition metal oxide having a spinel-type crystal structure.