Doped Cerium Oxide Electrode for Solid Oxide Cells
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Solution Overview
Problem
Conventional ceramic-supported solid oxide cells (SOCs) have low mechanical strength and are vulnerable to fracture, necessitating the development of metal-supported SOCs with improved mechanical robustness, thermal properties, and cost-effectiveness, while there is a specific need for enhanced air and fuel electrodes.
Innovation Solution
The use of a fuel electrode comprising a source of nickel and doped cerium oxide with a composition of Ce(1-x)Ln(x)O(2-0.5x-δ), where 0.001≤x≤0.08, Ln is Gd or Sm, and δ is the degree of oxygen deficiency, which improves electrode performance by enhancing current-voltage curves and reducing area-specific resistance as a function of temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional ceramic-supported SOCs are used, then the electrochemical function is maintained, but the mechanical strength is low and the structure is vulnerable to fracture
Solution Approach 1:
The patent employs a composite structure consisting of a metal support substrate (providing mechanical strength) combined with thin ceramic functional layers (providing electrochemical function). This composite approach allows the metal substrate to bear mechanical loads while the ceramic layers perform their electrochemical roles, thereby resolving the contradiction between mechanical strength and electrochemical functionality.
Solution Approach 2:
The patent utilizes thin ceramic films deposited on the metal support substrate. These thin films are not self-supporting but rely on the metal substrate for mechanical support. This approach enables the ceramic layers to be sufficiently thin to allow metal support to provide the necessary mechanical strength while maintaining the required electrochemical functionality.
2Strength
If metal-supported SOCs are used, then mechanical robustness and thermal properties are improved, but the ceramic layers must be deposited as thin non-self-supporting coatings
Solution Approach 1:
The patent changes the thickness parameter of the ceramic layers from conventional thick self-supporting structures to thin non-self-supporting coatings. This parameter change enables the metal support substrate to provide the necessary mechanical robustness while the thin ceramic layers perform their electrochemical functions, accepting the complexity of precise thin film deposition as a trade-off.
3Reliability
If doped cerium oxide with higher Ln content is used in the electrode, then the ion conductivity may improve, but the electrode performance and current-voltage characteristics deteriorate
Solution Approach 1:
The patent optimizes the compositional parameter x in Ce(1-x)Ln(x)O(2-0.5x-δ) to a specific range (0.001≤x≤0.08) where the electrode achieves optimal balance between ion conductivity and electrochemical performance. This parameter optimization ensures that the electrode maintains good current-voltage characteristics and reduced area-specific resistance while providing sufficient ion conductivity for fuel cell operation.
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 described electrode composition improves the electrochemical performance of SOC fuel electrodes, specifically enhancing current-voltage characteristics and reducing overpotential, leading to more robust and efficient operation across varying temperatures.
Implementation Method 1
the electrolyte of the SOFC conducts oxygen ions from a cathode to an anode located on opposite sides of the electrolyte
Implementation Method 2
SOC fuel cell units produce electricity using an electrochemical conversion process that oxidises fuel
Data Source
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AI summary
The invention provides an electrode for an electrochemical cell, the electrode comprising at least a first layer comprising a source of nickel and a first electrode material comprising doped cerium oxide of composition Ce(1-x)LnxO(2-0.5x-δ), where x is a doping level of between 0.001 and 0.08, Ln is Gd or Sm, and δ is the degree of oxygen deficiency. Also disclosed are electrochemical cells having such electrodes and stacks of such electrochemical cells. The invention also provides a method for producing an electrode for an electrochemical cell comprising applying an electrode composition as defined above to a substrate and optionally drying and sintering the composition to produce the electrode.