Solid Oxide Cell Oxygen Electrode Composition for Sr Diffusion Blocking
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Solution Overview
Problem
Solid oxide electrochemical cells face challenges with the formation of high-resistance phases at the interface between the oxygen electrode and the electrolyte, despite the introduction of ceria-based interlayers, due to thermal diffusion of strontium during firing, leading to reduced electrochemical performance.
Innovation Solution
Incorporating a strontium-containing perovskite-type composite oxide with tetravalent elements like titanium or cerium into the oxygen electrode material, which inhibits strontium diffusion and reduces the formation of SrZrO3 at the interface by introducing a rare-earth-doped cerium oxide interlayer between the oxygen electrode and the solid electrolyte.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ceria-based interlayer is introduced between the oxygen electrode and the electrolyte to prevent SrZrO3 formation, then the interface reaction is suppressed, but SrZrO3 with high resistance is still formed at the interface between the interlayer and the electrolyte due to Sr diffusion during heating
Solution Approach 1:
The patent introduces a perovskite-type oxide interlayer (e.g., LSMO, LSCO) between the ceria-based interlayer and the YSZ electrolyte. This new interlayer acts as a mediator that blocks Sr diffusion from the oxygen electrode to the electrolyte, preventing SrZrO3 formation at the critical interface while maintaining electrochemical performance.
Solution Approach 2:
The patent employs a composite structure consisting of multiple interlayers with different functions: a ceria-based interlayer for chemical stability and a perovskite-type oxide interlayer for Sr diffusion blocking. This composite approach combines the advantages of different materials to simultaneously address interface stability and Sr diffusion prevention.
2Object-affected harmful factors
If the oxygen electrode material is modified with tetravalent elements like Ti or Ce, then Sr diffusion is inhibited and SrZrO3 formation is prevented, but the electrode composition becomes more complex
Solution Approach 1:
The patent modifies the oxygen electrode material composition by incorporating tetravalent elements (Ti, Ce) into the perovskite structure. This compositional parameter change alters the diffusion properties of Sr, effectively blocking its migration to the electrolyte interface and preventing high-resistance layer formation.
3Object-affected harmful factors
If Sr diffusion is completely blocked to prevent SrZrO3 formation, then high-resistance phase formation is inhibited, but the electrochemical performance may be affected by excessive Sr retention in the electrode
Solution Approach 1:
The patent implements Sr diffusion blocking at the specific location where it is most critical - the interface between the interlayer and the electrolyte. The perovskite-type oxide interlayer provides localized Sr blocking capability at this critical interface, while allowing the bulk electrode to maintain its Sr content for optimal electrochemical performance.
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 effectively inhibits the formation of high-resistance phases, enhancing the electrochemical performance and efficiency of both solid oxide fuel cells and electrolysis cells by reducing thermal diffusion of strontium and improving power generation properties.
Implementation Method 1
Sr diffuses through an interlayer from an oxygen electrode, reaches the interface with YSZ, which is a solid electrolyte, and Sr reacts with Zr which has high reactivity with Sr to form SrZrO3
Implementation Method 2
when Ti or Ce are doped into an oxygen electrode material, diffusion of Sr is inhibited during heating
Implementation Method 3
the present inventors have focused on Ti which has higher reactivity with Sr than Zr
Implementation Method 4
Sr reacts with Zr which has high reactivity with Sr to form SrZrO3
Implementation Method 5
Solid oxide electrochemical cells include solid oxide electrolysis cells (SOEC) and solid oxide fuel cells (SOFC)
Implementation Method 6
Solid oxide electrochemical cells include solid oxide electrolysis cells (SOEC)
Data Source
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AI summary
A solid oxide electrochemical cell includes an oxygen electrode containing a strontium-containing perovskite-type composite oxide represented by Ln1-xSrxCo1-y-zFeyBzO3-δ (Ln is a trivalent lanthanide element, B is a tetravalent element, 0<x<1, 0≤y<1, 0<z<1, and 0<z+y<1, and δ is a value that is determined to satisfy charge neutrality conditions), a solid electrolyte containing zirconium oxide, a hydrogen electrode, and an interlayer containing a rare-earth-doped cerium oxide that is provided between the solid electrolyte and the oxygen electrode.